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diff --git a/14009-0.txt b/14009-0.txt new file mode 100644 index 0000000..0a565df --- /dev/null +++ b/14009-0.txt @@ -0,0 +1,4747 @@ +*** START OF THE PROJECT GUTENBERG EBOOK 14009 *** + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 787 + + + + +NEW YORK, January 31, 1891 + +Scientific American Supplement. Vol. XXXI., No. 787. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + * * * * * + + + + +TABLE OF CONTENTS. + + +I. BIOGRAPHY.--CHARLES GOODYEAR.--The life and discoveries of + the inventor of vulcanized India rubber, with portrait.--1 + illustration + +II. BIOLOGY.--Can we Separate Animals from Plants?--By ANDREW + WILSON.--A debated point well discussed.--The bases on which + distinctions must be drawn + +III. ELECTRICITY.--A New Electric Ballistic Target.--A target + for investigations of the velocity of projectiles, now in use at + the United States Military Academy, West Point, N.Y.--1 + illustration. + + Electric Erygmascope.--An electric lighting apparatus for + examining earth strata in bore holes for geologists' and + prospectors' use.--1 illustration + + The Electro-Magnet.--By Prof. SILVANUS THOMPSON.--Continuation + of this exhaustive treatise, giving further details on special + points of construction.--1 illustrations + +IV. ENTOMOLOGY.--Potash Salts.--The use of potash salts as + insecticides, with accounts of experiments + + The Outlook for Applied Entomology.--By Dr. C.V. RILEY, U.S. + entomologist.--The conclusion of Prof. Riley's lecture, treating + of the branch of entomology with which his name is so honorably + associated + +V. INSURANCE.--The Expense Margin in Life Insurance.--Elaborate + review of the necessary expenses of conducting the insurance of + lives, with tables and calculations + +VI. MATHEMATICS.--The Trisection of Any Angle.--By FREDERIC R. + HONEY, Ph.B.--A very ingenious demonstration of this problem, + based on the properties of conjugate hyperbolas + +VII. METEOROLOGY.--Note on the Mt. Blanc Meteorological Station + + The Flood at Karlsbad.--Account of the recent flood and of its + destructive effects.--1 illustration + +VIII. MECHANICAL ENGINEERING.--Station for Testing Agricultural + Machines.--A proposed establishment for applying dynamometer + tests to agricultural machines.--1 illustration + + Steam Engine Valves.--By THOMAS HAWLEY.--A review of modern + slide valve practice, the lap, cut-off, and other points.--6 + illustrations + +IX. MISCELLANEOUS.--Science in the Theater.--Curious examples of + stage effect in fictitious mesmerizing and hypnotizing.--4 + illustrations + + Theatrical Water Plays.--Recent episodes in real water plays at + Hengler's Circus, London.--2 illustrations + +X. NAVAL ENGINEERING.--The French Ironclad War Ship Colbert.--An + armored wood and iron ship, with central battery.--1 + illustration + +XI. PHYSIOLOGY AND HYGIENE.--Newer Physiology and Pathology.--By + Prof. SAMUEL BELL. M.D.--An excellent presentation of modern + practice in the light of bacteriology + + Test Card Hints.--How to test the eyes for selecting eyeglasses + and spectacles + + The Composition of Koch's Lymph.--What Prof. Koch says it is and + what it can do.--The cabled account of the disclosure so long + waited for + +XII. TECHNOLOGY.--Firing Points of Various Explosives.--The + leading explosives, with the temperature of their exploding + points tabulated + + The Recovery of Gold and Silver from Plating and Gilding + Solutions--A paper of interest to silver and gold platers, as + well as photographers + + Water Softening and Purifying Apparatus.--An apparatus for + treatment of sewage, etc., chemically and by deposition.--1 + illustration + + * * * * * + + + + +THE FRENCH IRONCLAD WAR SHIP COLBERT. + + +The central battery ironclad Colbert is one of the ten ships of the +French navy that constitute the group ranking next in importance to +the squadron of great turret ships, of which the Formidable is the +largest. The group consists of six types, as follows: + + 1. The Ocean type; three vessels; the Marengo, Ocean, and Suffren. + 2. The Friedland type, of which no others are built. + 3. The Richelieu type, of which no others are built. + 4. The Colbert type, of which there are two; the Colbert and the + Trident. + 5. The Redoubtable type, of which no others are built. + 6. The Devastation type, of which no others are built. + +[Illustration: THE FRENCH IRONCLAD WAR SHIP COLBERT.] + +The Colbert was launched at Brest in 1875, and her sister ship, the +Trident, in 1876. Both are of iron and wood, and the following are the +principal dimensions of the Colbert, which apply very closely to the +Trident: She is 321 ft. 6 in. long, 59 ft. 6 in. beam, and 29 ft. 6 +in. draught aft. Her displacement is 8,457 tons, her indicated horse +power is 4,652, and her speed 14.4 knots. She has coal carrying +capacity for 700 tons, and her crew numbers 706. The thickness of her +armor belt is 8.66 in., that protecting the central battery is 6.29 +in. thick, which is also the thickness of the transverse armored +bulkheads, while the deck is 0.43 in. in thickness. The armament of +the Colbert consists of eight 10.63 in. guns, two 9.45 in., six 5.51 +in., two quick firing guns, and fourteen revolving and machine +guns.--_Engineering._ + + * * * * * + +A compound locomotive, built by the Rhode Island Locomotive Works, has +been tried on the Union Elevated Railroad, Brooklyn, N.Y. The engine +can be run either single or compound. The economy in fuel was 37.7 per +cent, and in water 23.8 per cent, over a simple engine which was +tested at the same time. The smoothness of running and the stillness +and comparative absence of cinders was fully demonstrated. + + * * * * * + + + + +STEAM ENGINE VALVES. + +[Footnote: Lecture delivered at Wells Memorial Institute, Boston, in +the Lowell Free Course for Engineers. From report in the _Boston +Journal of Commerce_.] + +By THOMAS HAWLEY. + +RIDING CUT-OFF VALVES--PECULIARITIES AND MERITS OF THE DIFFERENT +STYLES. + + +In considering the slide valve in its simple form with or without lap, +we find there are certain limitations to its use as a valve that would +give the best results. The limitation of most importance is that its +construction will not allow of the proper cut off to obtain all the +benefits of expansion without hindering the perfect action of the +valve in other particulars. At this economical cut off the opening of +the steam port is very little and very narrow, and although this is +attempted to be overcome by exceedingly wide ports, sixteen inches in +width in many cases in locomotive work, this great width adds largely +to the unbalanced area of the valve. The exhausting functions of the +valve are materially changed at the short cut off, and when much lap +is added to overcome this defect, there usually takes place a choking +of the exhaust port. You might inquire, why not make the port wider, +but this would increase the minimum amount of load on the valve, and +this must not be overlooked. Then the cut off is a fixed one, and we +can govern only by throttling the pressure we have raised in the +boiler or by using a cut off governor and the consequent wastes of an +enormous clearance space. You will observe, therefore, that the plain +slide valve engine gives the most general satisfaction at about +two-thirds cut off and a very low economic result. The best of such +engines will require forty-five to fifty pounds of steam per horse +power per hour, and to generate this, assuming an evaporation of nine +pounds of water to a pound of coal, would require between five and six +pounds of coal per horse power per hour. And the only feature that the +valve has specially to commend it is its extreme simplicity and the +very little mechanism required to operate it. + +Yet this is of considerable importance, and in consideration of some +special features at its latest cut off, the attempt has been many +times made to take advantage of these features. For instance, at 90° +advance, the valve opens very rapidly indeed and fully satisfies our +requirements of a perfect valve. This is one good point, and in this +position also the exhaust and compression can be regulated very +closely and as desired without much lap, and as the opening of the +exhaust port comes with the eccentric at its most rapid movement the +release is very quick and as we would have it. This is only possible +at the most uneconomic position of the valve as regards cut off. + +The aim of many engineers has been to take advantage of these matters +by using the valve with 90° angular advance of eccentric ahead of +crank, for the admission, release, and compression of the steam, and +provide another means of cutting off, besides the one already referred +to, viz., cutting off the supply of steam to the chest, and overcome +the objection in this one of large clearance spaces. This is done by +means of riding cut off valves, often called expansion valves, of +which, perhaps, the most widely known types in this vicinity are the +Kendall & Roberts engine and the Buckeye. The former is used in the +simplest form of riding cut off, while the Buckeye has many peculiar +features that engineers, I find, are too prone to overlook in a casual +examination of the engine. In these uses of the slide valve, too, +means are suggested and carried out of practically balancing the +valve. + +The origin of the riding cut off is most generally attributed to +Gonzenbach. His arrangement had two steam chests, the lower one +provided with the ordinary slide valve of late cut off, and steam was +cut off from this steam chest by the expansion valve covering the +ports connecting with the upper steam chest. This had the old +disadvantage that all the steam in the lower chest expanded with that +in the cylinder, at a consequent considerable loss. This was further +improved by causing the riding cut off to be upon the top of the main +valve, instead of its chest, and resulted in a considerable reduction +of the clearance space. + +This is the simplest form, and is shown in Fig. 1. The steam is +supplied by a passage through the main valve which operates exactly as +an ordinary slide valve would. That is, the inside edges of the steam +passage are the same as the ordinary valve, the additional piece on +each end, if I may so term it, being merely to provide a passage for +the steam which can be closed, instead of allowing the steam to pass +the edge. The eccentric of the main valve is fastened to the shaft to +give the proper amount of lead, and the desired release and +compression, and the expansion valve is operated by a separate +eccentric fastened in line with or 180° ahead of the crank. When the +piston, therefore, commences to move from the crank end to open the +port, D, the expansion valve is forced by its eccentric in the +opposite direction, and is closing the steam port and would have +closed it before the piston reached quarter stroke, thus allowing the +steam then in the cylinder to do work by expansion. The eccentric +operating this expansion valve may be set to close this steam port at +any point in the stroke that is desired, the closing occurring when +the expansion valve has covered the steam port. Continuing the +movements of the valves, the two would move together until one or the +other reached its dead center, when the movements would be in opposite +directions. + +[Illustration: FIG. 1.] + +There are three ways of effecting the cut off in such engines, the +main valve meanwhile being undisturbed, its eccentric fastened +securely so as not to disturb the points of lead, release, and +compression. All that is required is to cause the edge of the +expansion valve to cover the steam port earlier in the stroke, and +this can be done, first, by increasing the angular advance of the cut +off eccentric; second, by adding lap to the cut off valve; and third +by changing the throw of the eccentric. In all these instances the +riding valve is caused to reach the edge of the steam port earlier in +the stroke. We will take first, as the simplest, those methods by +which the lap of the cut off valve is increased. + +It will be noted that there is but one edge of this valve that is +required to do any work, and that is to close the valve. The +eccentrics are so placed that the passage in the main valve is opened +long before the main valve itself is ready to admit steam to the +cylinder, so that only the outer edges are the ones to be considered, +and it will be readily seen that the two valves traveling in opposite +directions, any lap added to the working edge of the cut off valve +will cause it to reach the edge and therefore close the port earlier +than it would if there was less lap. And we might carry it to the +extreme that we could add lap enough that the steam passage would not +be opened at all. + +In Fig. 2 is shown the method by which this is accomplished, in what +is called Meyer's valve, and such as is used in the Kendall & Roberts +engine. We have only one point to look after, the cut off, so we can +add all the lap we wish without disturbing anything else. In this +engine the lap is changed by hand by means of a little hand wheel on a +stem that extends out of the rear of the steam chest. The valve is in +two sections, and when it is desired to cut off earlier, the hand +wheel is turned in such a direction that the right and left hand +screws controlling the cut off valve move one valve portion back and +the other forward, which would, if they were one valve and they should +be so considered, have the effect of lengthening them, or adding lap +to them. The result would be that the riding valve would reach the +edge of the steam port earlier in the stroke, bringing about an +earlier cut off. If the cut off is desired to be later, the hand wheel +is so turned that the right and left hand screws will bring the valve +sections nearer together, thus practically taking off lap. Now this +may be done by hand or it may be done by the action of a governor. + +[Illustration: FIG. 2.] + +In the latter case the governor at each change of load turns the right +and left hand screws to add or take away lap, as the load demands an +earlier or later cut off; in other cases the governor moves a rack in +mesh with a gear by which the valve sections are brought closer +together or are separated. The difficulty with the case where the hand +wheel is turned by hand is that the cut off is fixed where you leave +it, and governing can only be at the throttle. For this reason +anywhere near full boiler pressure would not be obtained in the +cylinder of the engine. If the load was a constant one, and the cut +off could be fixed at about one-third, causing the throttle to open +its widest, very good results would be obtained, but there is no +margin left for governing. + +If the load should increase at such a time the governor could not +control it under these conditions, and it would lead to a decrease in +speed unless the lap was again changed to give a later cut off. On +this account the general practice soon becomes to leave the cut off at +the later point and give range to the throttle, and we come back once +more to the plain slide valve cutting off at half stroke, and the only +gain there is, is in a quick port opening and quick cut off. But these +matters are more than offset by the wire drawing between the steam +pipe and chest, through the throttle, and the fact that there is added +to the friction of the engine the friction of this additional slide +valve and a considerable liability to have a leaky valve. + +In the case where the governor changes the position of the cut off +valve a greater decree of economy would result. In this engine, of +which the Lambertville engine is a type, the main valve is a long D +slide, with multiple ports at the ends through which the steam enters +the cylinders. It is operated from an eccentric on the crank shaft in +the usual manner. The cut off valve is also operated from the motion +on an eccentric fixed upon the crank shaft. The rod or stem of the cut +off valve passes through the main valve rod and slide. Upon the outer +end of the cut off valve rod are tappets fastened to engage with +tappets on the eccentric valve rod. Connection between the cut off +eccentric, therefore, and the cut off valve is only by means of the +engagement of these tappets. The eccentric rod is fastened to a rocker +arm having motion swinging about a pin or bearing in the governor +slide, which may be raised or lowered by a cam operated by the +governor. The cut off slide is of cylindrical shape and incloses a +spring and dash pot with disks attached by means of which the valve is +closed. The motion for operating the valves is relatively in the same +direction, the cut off eccentric having the greatest throw and greater +angular advance to cause it to open earlier and quickly before the +main valve is ready to admit steam. The cut off eccentric rod swinging +the rocker arm, the tappets thereon engage with those upon the cut off +valve rod and open the passages to the main valve, and in their +movement compress the spring in the main valve. According as the speed +of the engine, the rock arm will be raised or lowered so that the +tappets upon the eccentric rod may keep in engagement a shorter or +longer time before they disengage, thus allowing the spring that has +been compressed by the movement of the cut off valve to close that +valve quickly and the supply of steam to the engine, the cut off valve +traveling with the main valve for the balance of the stroke. This +device will give a remarkably quick opening and a quick cut off, but +in view of the fact that the governor has so much to do, its delicacy +is impaired and a quick response to the demands of the load changing +not so likely to occur. The cut off cannot be as quick as in some +other engines, because the valves are moving in opposite directions, +and while this fact would help, so far as shortening the distance to +be traveled before cut off, the resistance of the valves to travel in +opposite directions, or rather the tendency of the valve to travel +with the main valve, hinders its rapid action. + +[Illustration: FIG. 3.] + +This is one great objection to the rack and gear operated by the +governor, that two flat valves riding upon each other and sliding in +opposite directions at times require a considerable amount of force to +move them, and as only a slight change in load is required by the +load, the governor cannot handle the work as delicately as it should. +It is too much for the governor to do well. To overcome this +difficulty the Ryder cut-off, shown in Fig. 3, was made by the +Delamater people, of New York. The main slide valve is hollowed in the +back and the ports cut diagonally across the valve to form almost a +letter V. The expansion valve is V-shaped, and circular to fit its +circular-seat. The valve rod of the expansion valve has a sector upon +it and operated by a gear upon the governor stem, which rotates the +valve rod, and the edge of the valve rod is brought farther over the +steam port, thus practically adding lap to the valve. Little movement +is found necessary to make the ordinary change in cut-off, and it is +found to be much easier to move the riding valve across the valve than +in a direction directly opposite. It would require considerable force +to move the upper valve by the governor faster than the lower, or in a +direction opposite to that in which it is moving, but very little +force applied sideways at the same time it is moving forward will give +it a sideways motion. In this device the governor has only to exert +this side pressure and therefore has less to do than if it were called +upon to move the upper valve directly against the movement of the +lower. + +Something similar is the valve of the Woodbury engine, of Rochester, +N.Y. The cut-off valve is cylindrical, covering diagonal ports +directly opposite, and is caused to be rotated by the action of the +governor that operates a rack in mesh with a segment. Very little +movement will effect a considerable change in the lappage of the +valve, the valve turning about one-quarter a revolution for the +extremes of cut off. The cut off valve rod works through a bracket and +its end terminates in a ball in a socket on the end of the eccentric +rod. In this case the governor has not as much to do as in other +instances. + +[Illustration: FIG. 4.] + +Still another method of effecting this change in cut off, but hardly +by increasing the lap of the valve, is shown in the next drawing, Fig. +4. The cut off valve is held upon the main valve by the pressure of +steam upon its back and rides with it until it comes in contact with +the cut off wedge-shaped blocks, when its motion is arrested, and the +main valve continuing its movement the steam port is closed by the +main valve passing beneath the cut off valve. Thus the main valve +travels and carries the cut off valve upon its back again until the +cut off valve strikes the wedge on the other end and the cut off is +effected. The relative positions of the blocks are determined by the +governor, that will raise or lower them so that the cut off valve will +engage with them earlier or later as desired. This device was designed +specially as an inexpensive method of changing the common slide valve +into an automatic cut off. The cut off would not be as quick as in +other cases we have cited, depending here upon the movement of the +lower valve alone, and that, too, is in its slowest movement; whereas +in the other cases, the edges approaching each other, by the differing +movement of the valves the cut off is very rapid, provided the +distance to travel is not long. In this device considerable noise must +result by the cut off valve striking the cut off blocks, and a +considerable amount of leakage is likely to occur past this valve. + +But there is one great objection in the valve gears thus far cited, +that the travel of the expansion valve upon the main valve is +variable. I have in mind the case of a Kendall & Roberts engine, which +had been run for a long time at no better economy than would be +obtained from a plain slide valve engine, and when it was attempted to +get an earlier cut off by separating the two cut off valves, they had +worn so much in their old place on the valve that shoulders were found +sufficient to cause a disagreeable noise and a leaky valve. This is +very apt to occur, not only where the valve is run for a long time on +one seat, but in cases of variation of the travel of the expansion +valve. The result is that a change will bring about a leaky valve, +something that every engineer abhors. + +The construction of the Buckeye engine, which is also of this type, is +such that the travel of the valve on the back of the main valve is +always the same, no matter what the cut off may be. Then this engine +makes use of our second proposition as a means of effecting the cut +off, viz., by advancing the eccentric. You will readily observe that +anything that will cause the cut off valve to reach a certain point +earlier in the stroke will bring about an earlier cut off as it +hastens everything all around. This is the plan pursued in the +Buckeye, in which the governor, of the shaft type, turns the eccentric +forward or back according as the load demands. Then, in addition, the +valve is balanced partially, the attempt not being made to produce an +absolutely balanced valve, on the ground that there should be friction +enough to keep the surfaces bright and to prevent leakage. The most +perfect valve will, of course, be entirely balanced under all +conditions of pressure so as to move with perfect ease. With the +riding cut off valve in connection with the plain slide valve, this is +not accomplished, and it does not matter whether it is partially +unbalanced to prevent leakage or not, the fact that it is not entirely +balanced prevents it reaching the ideal valve. + +[Illustration: Fig. 5] + +This valve, Fig. 5, differs from the others also in this particular, +that the exhaust takes place at the end of the valve instead of under +the arch. Two eccentrics are used, the one for the main valve being +fastened to the shaft and the other riding loosely upon it and +connected to the fly wheel governor, by which it may be turned forward +or back as the load requires. The three points of lead, or admission +and exhaust and compression, are fixed and independent of the changes +and cut off. The motion of the main eccentric is given to a rocker +arm, the pivot of which is at the bottom, and from the upper end the +valve rod transfers the motion to the valve without reversing the +motion, as is done sometimes in the slide valve to overcome the +effects of the angularity of the connecting rod. The action of the +rocker arm, therefore, so far as the main valve in the Buckeye is +concerned, is no different than that which would occur if no rocker +arm intervened. The motion of the cut off eccentric, through its +eccentric rod, is given to a rocker rocking in a bearing in the center +of the main rocker arm (see Fig. 6). The motion of this eccentric is +reversed, so far as the cut off valve is concerned, and when the cut +off eccentric is moving forward, the cut off valve is being pushed +back. The main valve rod is hollow, and the cut off valve rod passes +through it. + +[Illustration: Fig. 6] + +The cut off eccentric can be placed in any position to cause it to cut +off as desired, and by drawing the valve forward, by increasing the +angular advance of the eccentric, the cut off valve is caused to reach +and cover the steam passage in the main valve earlier in the stroke. +Instead of being ahead of the crank, the main eccentric in this +arrangement follows the crank, on account of the exhaust and steam +edges being exactly opposite from those in the ordinary slide. What is +the steam edge of the common slide is in this the exhaust edge, and +what is the exhaust edge in the common valve is the steam edge in this +one. The valve, therefore, must be moved in the opposite direction +from what is ordinarily the case, the main eccentric being not 90 deg. +behind the crank. It has a rapid and full opening just the same, for +it is at this point behind the crank, or ahead of it, that the +eccentric gives to the valve its quickest movement, or between the +eccentric dead centers. The cut off eccentric is considerably ahead of +the main eccentric, and about even with the crank. If it was not for +the reversal of motion of the cut off valve through the rocker arm +this eccentric would be about in line with the crank, but on the other +end. The movement of the cut off valve, therefore, at the time of port +opening is very little, being about on its dead center, passing which, +it immediately commences to close. + +The object of the peculiar construction of the rocker arm, and the +pivot for the cut off rocker being placed thereon, is to provide equal +travel on the back of the main valve, no matter what the cut off. I +have already explained, in connection with the slide valve, that +advancing the eccentric does not change the movement of the valve on +its seat, but simply its relation to the movement of the piston. You +will see that this is unchanged as using the main valve as a seat or +any other seat. If the main valve was to remain stationary, and only +the cut off valve to be operated by its eccentric, the movement of +this cut off valve on a certain plane would be the same for all +positions of the eccentric. + +Moving the main slide does not affect the matter in any way, for it +moves at the same time the pivot of the cut off, and while the cut off +seat has assumed a different position with reference to the engine, it +is still as though stationary so far as the cut off valve is +concerned. This is the object of this peculiar construction, and not, +as some engineers suppose, simply to make an odd way of doing things. +And the object of it all is to give at all cut offs the same amount of +travel, so that there might be no unequal wear to bring about a leak, +to prevent which a perfect balancing has been sacrificed. + +Referring to the valve and this engine as to how it will satisfy our +requirements of a perfect valve gear, we find that the first +requirement of a rapid and full opening is met, in that the opening +occurs when the main eccentric is moving very rapidly, yet not its +fastest, and while this opening will be very satisfactory, it is not +so rapid an opening as is obtained in some other forms of valves and +valve gears, but this could be overcome very readily by increasing the +lead a trifle, and in my experience with these engines I find that the +practice is very general by engineers and by builders themselves to +give them a considerable amount of lead. As to the second requirement, +the maintenance of initial pressure until cut off, giving a straight +steam line, cards from this engine will not be found to show that the +engine satisfies this requirement, and for this reason, that the +cut-off valve commences to close the port immediately after the piston +commences to move. The cut off eccentric you will remember is set to +move with the crank or very nearly so, and the lighter the load, the +greater will this fact appear. For the lightest loads the governor +places the eccentric in advance of the crank, so that the cut off +valve will commence to close the port before steam is admitted by the +main valve to the engine. Now, the later the cut off, the less will +this wire drawing appear at first, and the shorter the cut off, the +amount of wire drawing increases sensibly. The operation of the valve, +therefore, in this particular, cannot be considered as meeting our +requirement that the port shall be held open full width until ready to +be closed. Many men claim for this engine that the closing occurs when +the cut off eccentric is moving its fastest. This is a fact, and if we +consider the point of cut off only to be the point of absolute cut +off, the cut off must be instantaneous, for there is an instantaneous +point where the cut off is final only to be considered. The reasoning +applied here would hold good also to a less extent on the slide valve, +but is not the point of absolute cut off. We want to note how long it +is from the time the valve commences to close at all until finally +closed, and, as I have shown you, this is considerable in this engine. + +Referring to the point of cut off finally, it is determined upon by a +governor of the fly wheel type. The eccentric is loose about the +shaft, and arms projecting therefrom are connected by other arms to +the extremity of an arm upon which is mounted a weight, and which is +attached to the spokes of the fly wheel, or special governor wheel in +this case, and which is fastened to the crank shaft. As the speed +increases through throwing off a portion of the load the governor +weights fly out, and this movement is transferred through the lever +connections to the eccentric, causing it to be turned ahead, and the +manner hastening the movement of the cut off valve on its seat and +causing it to reach and cover the edge of the steam port earlier in +the stroke. This engine was the pioneer in governors of this +character, the advantage being, in addition to its necessity for the +work of turning the eccentric ahead or back, that the liability of the +engine to run away, as very often happens from the breaking of the +governor belt or a similar cause, was not possible. + +The cut off valve has a travel considerably beyond the edge of the +steam passage after the valve is closed, and this has one advantage, +that the valve is less liable to leak, and to this must be added the +loss from the friction of this moving valve, and moving too in +opposition to the main valve. In our perfect valve, as we outlined it, +the valve does not move after the port is closed. The exhausting +functions of the valve are very good, giving a quick opening and a +full opening, because this opening occurs when the eccentric is moving +its fastest. The engine also possesses a distinct advantage in having +remarkably small clearance spaces. The length of the steam passage is +very small in comparison with any form of engine, and having but two +ports instead of four, as in the Corliss and four valve type. + +In these there must be included in the clearance, that to the exhaust +port as well as the steam port, adding a considerable amount where the +piston comes close to the head. As the engines leave the maker's hand +the engines are provided with a considerable amount of lap to give +plenty of compression, but are, of course, capable of having more +added to increase compression, or some planed off to decrease it. + +One of the peculiar things about this engine is the failure to realize +anywhere near boiler pressure, noticeable in every case that has come +under my notice. The considerable lead gives it for an instant, but it +soon falls away, indicating the steam chest pressure only by a peak at +the junction of the admission and steam lines. This is probably due to +the fact that the cut off valve commences closing the steam passage so +soon after steam is admitted, and in this particular does not satisfy +the requirements of a perfect valve. There is this about the engine, +that above all others of this type there has come under my notice +fewer engines of this type with a maladjustment of valves from +tampering by incompetent engineers. + + * * * * * + + + + +FIRING POINTS OF VARIOUS EXPLOSIVES. + + +An apparatus, devised by Horsley, was used, which consisted of an iron +stand with a ring support holding a hemispherical iron vessel, in +which paraffin or tin was put. Above this was another movable support, +from which a thermometer was suspended and so adjusted that its bulb +was immersed in molten material in the iron vessel. A thin copper +cartridge case, 5/8 in. in diameter and 1-5/16 in. long, was suspended +over the bath by means of a triangle, so that the end of the case was +1 in. below the surface of the liquid. On beginning the experiment the +material in the bath was heated to just above the melting point, the +thermometer was inserted in it, and a minute quantity of the explosive +was placed in the bottom of the cartridge case. The temperature marked +by the thermometer was noted as the _initial temperature_, the +cartridge case containing the explosive was inserted in the bath, and +the temperature quickly raised until the explosive flashed off or +exploded, when the temperature marked by the thermometer was again +noted as the _firing point_. The tables given show the results of +about six experiments with each explosive. The initial temperatures +range from 65° to 280° C. in some cases, but as the firing points +remained fairly constant, only the extremes of the latter are quoted +in the following table: + + + --------------------------------+----------------------- + Description of Explosive. | Firing Point in ° C. + --------------------------------+----------------------- + Compressed military gun-cotton. | 186 - 201 + Air-dried military gun-cotton. | 179 - 186 + " " " | 186 - 189 + " " " | 137 - 139 + " " " | 154 - 161 + Gun-cotton dried at 65° C. | 136 - 141 + Air-dried collodion gun-cotton. | 186 - 191 + " " " | 197 - 199 + " " " | 193 - 195 + Air-dried gun-cotton. | 192 - 197 + " " | 194 - 199 + Hydro-nitrocellulose. | 201 - 213 + Nitroglycerin. | 203 - 205 + Kieselghur dynamite. No. 1. | 197 - 200 + Explosive gelatin. | 203 - 209 + Explosive gelatin, camphorated. | 174 - 182 + Mercury fulminate. | 175 - 181 + Gunpowder. | 278 - 287 + Hill's picric powder. | 273 - 283 + " " " | 273 - 290 + Forcite, No. 1. | 184 - 200 + Atlas powder, 75 per cent. | 175 - 185 + Emmensite, No. 1. | 167 - 184 + Emmensite, No. 2. | 165 - 177 + Emmensite, No. 5. | 205 - 217 + --------------------------------+----------------------- + _--C.E. Munroe, J. Amer. Chem. Soc._ + + + * * * * * + + + + +STATION FOR TESTING AGRICULTURAL MACHINES. + + +The minister of agriculture has recently established a special +laboratory for testing agricultural _materiel_. This establishment, +which is as yet but little known, is destined to render the greatest +services to manufacturers and cultivators. + +In fact, agriculture now has recourse to physics and mechanics as well +as to chemistry. Now, although there were agricultural laboratories +whose mission it was to fix the choice of the cultivator upon such or +such a seed or fertilizer, there was no official establishment +designed to inform him as to the value of machines, the models of +which are often very numerous. _Chemical_ advice was to be had, but +_mechanical_ advice was wanting. It is such a want that has just been +supplied. Upon the report presented by Mr. Tisserand, director of +agriculture, a ministerial decree of the 24th of January, 1888, +ordered the establishment of an experimental station. Mr. Ringelmann, +professor of rural engineering at the school of Grignon, was put in +charge of the installation of it, and was appointed its director. He +immediately began to look around for a site, and on the 17th of +December, 1888, the Municipal Council of Paris, taking into +consideration the value of such an establishment to the city's +industries, decided that a plot of ground of an area of 3,309 square +meters, situated on Jenner Street, should be put at the disposal of +the minister of agriculture for fifteen years for the establishment +thereon of a trial station. This land, bordering on a very wide street +and easy of access, opposite the municipal buildings, offers, through +its area, its situation, and its neigborhood, indisputable advantages. +A fence 70 meters in extent surrounds the station. An iron gate opens +upon a paved path that ends at the station. + +The year 1889 was devoted to the installation, and the station is now +in full operation. The tests that can be made here are many, and +concern all kinds of apparatus, even those connected with the electric +lighting that the agriculturist may employ to facilitate his +exploitation. However, the tests that are oftenest made are (1) of +rotary apparatus, such as mills, thrashing machines, etc.; (2) of +traction machines, such as wagons, carts, plows, etc.; and (3) of +lifting apparatus. It is possible, also, to make experiments on the +resistance of materials. + +The experimental hall contains a 7 horse power gas motor, dynamometers +with automatic registering apparatus, counters, balances, etc. A small +machine shop contains a lathe, a forge, a drilling machine, etc. The +main shaft is 12 meters in length and is 7 centimeters in diameter. It +is supported at a distance of one meter from the floor by four pillow +blocks, and is formed of three sections united by movable coupling +boxes. Out of these 12 meters, 9 are in the hall and 3 extend beyond +the hall to an annex, 14 meters in length and 4 in width, in which +tests are made of machines whose operation creates dust. When the +machines to be tested require more than the power of seven horses that +the motor gives, the persons interested furnish a movable engine, +which, placed under the annex, actuates the driving shaft. Alongside +of the main building there is a ring for experimenting upon machines +actuated by a horse whim. There will soon be erected in the center of +the grounds an 18 meter tower for experiments on pumps. Platforms +spaced 5 meters apart, a crane at the top, and some gauging apparatus +will complete this hydraulic installation. + +The equipment of the hall is very complete, and is fitted for all +kinds of experiments. + +[Illustration: STATION FOR TESTING AGRICULTURAL MACHINES--DYNAMOMETER + FOR TESTING ROTARY MACHINES.] + +The tests of rotary machines are made by means of a dynamometer (see +figure). Two fast pulleys and one loose pulley are interposed between +the machine to be tested and the motor. The pulley connected with the +motor carries along the one connected with the machine, through the +intermedium of spring plates, whose strength varies with the nature of +the apparatus to be tested. The greater or less elongation of these +plates gives the tangential stress exerted by the driving pulley to +carry along the pulley that actuates the machine to be tested. This +elongation is registered by means of a pencil connected with the +spring plates, and which draws a diagram upon a sheet of paper. At the +same time, a special totalizer gives the stress in kilogrammeters. +Besides, the pulley shaft actuates a revolution counter, and a clock +measures the time employed in the experiment. In order to obtain a +simultaneous starting and stopping point for all these apparatus, they +are connected electrically, and, through the maneuver of a commutator, +are all controlled at once. The electric current is furnished by two +series of bichromate batteries. + +The tests of traction machines are effected by means of a +three-wheeled vehicle carrying a dynamometer. The front wheel is +capable of turning freely in the horizontal plane, and the dynamometer +is mounted upon a frame provided with a screw that permits of +regulating its position according to the slope of the ground. The +method of suspension of the dynamometer allows it to take +automatically the inclination of the line of traction without any +torsion of the plates. There are two models of this vehicle, one +designed to be drawn by a man, and the other by a horse. + +The station is provided, in addition, with registering pressure +gauges, a large double dynamometric indicator, a counter of +electricity, balances of precision, etc. + +An apparatus designed for measuring the rendering of presses is now in +course of construction. + +Although the station has been in operation only from the 1st of +January, twenty-five machines have already been presented to be +tested.--_Extract from Le Genie Civil_. + + * * * * * + + + + +WATER SOFTENING AND PURIFYING APPARATUS. + + +We have recently had brought under our notice a system of water and +sewage purification which appears to possess several substantial +advantages. Chief among these are simplicity in construction and +operation, economy in first cost and working and efficiency in action. +This system is the invention of Messrs. Slack & Brownlow, of Canning +Works, Upper Medlock Street, Manchester, and the apparatus adopted in +carrying it out is here illustrated. It consists of an iron +cylindrical tank having inside a series of plates arranged in a spiral +direction around a fixed center, and sloping downward at a +considerable angle outward. The water to be purified and softened +flows through the large inlet tube to the bottom, mixing on its way +with the necessary chemicals, and entering the apparatus at the +bottom, rises to the top, passing spirally round the whole +circumference, and depositing on the plates all solids and impurities. + +All that is needed in the way of attention, even when dealing with +sewage, or the most polluted waters, is stated to be the mixing in the +small tanks the necessary chemical reagents, at the commencement of +the working day; and at the close of the day the opening of the mud +cocks shown in our engraving, to remove the collected deposit upon the +plates. For the past six months this system has been in operation at a +dye works in Manchester, successfully purifying and softening the +foul waters of the river Medlock. It is stated that 84,000 gallons per +day can be easily purified by an apparatus 7 feet in diameter. The +chemicals used are chiefly lime, soda, and alumina, and the cost of +treatment is stated to vary from a farthing to twopence per 1,000 +gallons, according to the degree of impurity of the water or sewage +treated. + +The results of working at Manchester show that all the visible filth +is removed from the Medlock's inky waters, besides which the hardness +of the water is reduced to about 6° from a normal condition of about +30°. The effluent is fit for all the varied uses of a dye works, and +is stated to be perfectly capable of sustaining fish life. With +results such as these the system should have a promising future before +it in respect of sewage treatment, as well as the purification and +softening of water generally for industrial and manufacturing +purposes.--_Iron._ + +[Illustration: WATER SOFTENING AND PURIFYING APPARATUS.] + + * * * * * + + + + +THE TRISECTION OF ANY ANGLE. + +By FREDERIC R. HONEY, Ph.B., Yale University. + + +The following analysis shows that with the aid of an hyperbola any +arc, and therefore any angle, may be trisected. + +If the reader should not care to follow the analytical work, the +construction is described in the last paragraph--referring to Fig. II. + +Let a b c d (Fig. I.) be the arc subtending a given angle. Draw the +chord a d and bisect it at o. Through o draw e f perpendicular +to a d. + +We wish to find the locus of a point c whose distance from a given +straight line e f is one-half the distance from a given point d. + +In order to write the equation of this curve, refer it to the +co-ordinate axes a d (axis of X) and e f (axis of Y), intersecting +at the origin o. + + Let g c = x + +Therefore, from the definition c d = 2x + + Let o d = D + [Hence] h d = D-x + + Let c h = y + [Hence] (2x)² = y² + (D-x)² + or 4x² = y² + D²-2Dx + x² + [Hence] y²-3x² + D²-2Dx = o [I.] + +This is the equation of an hyperbola whose center is on the axis of +abscisses. In order to determine the position of the center, eliminate +the x term, and find the distance from the origin o to a new origin +o'. + + Let E = distance from o to o' + [Hence] x = x' + E + +Substituting this value of x in equation I. + + y²-3(x' + E)² + D²-2D(x' + E) = o + or y²-3x²-6Ex'-3E² + D²-2Dx'-2DE = o [II.] + +In this equation the x' terms should disappear. + + [Hence] -6Ex' - 2Dx' = o + [Hence] -E = - D/3 + +That is, the distance from the origin o to the new origin or the +center of the hyperbola o' is equal to one-third of the distance +from o to d; and the minus sign indicates that the measurement +should be laid off to the left of the origin o. Substituting this +value of E in equation II., and omitting accents-- + + We have + + y² - 3x² + 2Dx - D²/3 + D² - 2Dx + 2D²/3 = o + [Hence] y² - 3x² = - 4D²/3 + +[Illustration: Fig I] + +[Illustration: Fig II] + +This is the equation of an hyperbola referred to its center o' as +the origin of co-ordinates. To write it in the ordinary form, that is +in terms of the transverse and conjugate axes, multiply each term by +C, i.e., + __ + Let \/C = semi-transverse axis. + +[TEX: \sqrt{C} = \text{semi-transverse axis.}] + + Thus Cy² - 3Cx² = - 4CD²/3. [III.] + +When in this form the product of the coefficients of the x² and y² +terms should be equal to the remaining term. + +That is + + 3C² = - 4CD²/3. + [Hence] C = 4D²/9. + +And equation III. becomes: + + + 4D² 4D² 16D^{4} + ----- y² - ----- x² = - --------- + 9 3 27 + +[TEX: \frac{4D^2}{9} y^2 - \frac{4D^2}{3} x^2 = -\frac{16D^4}{27}] + ____ + / 4D² 2D + The semi-transverse axis = \/ ----- = ---- + 9 3 + +[TEX: \text{The semi-transverse axis} = \sqrt{\frac{4D^2}{9}} += \frac{2D}{3}] + ____ + / 4D² 2D + The semi-conjugate axis = \/ ----- = ----- + 3 ___ + \/ 3 + +[TEX: \text{The semi-conjugate axis} = \sqrt{\frac{4D^2}{3}} += \frac{2D}{\sqrt{3}}] + +Since the distance from the center of the curve to either focus is +equal to the square root of the sum of the squares of the semi-axes, +the distance from o' to either focus + + ____________ + /4D² 4D² 4D + = /\ /----- + ----- = ---- + \/ 9 3 3 + +[TEX: \sqrt{\frac{4D^2}{9} + \frac{4D^2}{3}} = \frac{4D}{3}] + +We can therefore make the following construction (Fig. II.) Draw a d +the chord of the arc a c d. Trisect a d at o' and k. Produce +d a to l, making a l = a o' = o' k = k d. With a k as a +transverse axis, and l and d as foci, construct the branch of the +hyperbola k c c' c", which will intersect all arcs having the common +chord a d at c, c', c", etc., making the arcs c d, c' d, c" +d, etc., respectively, equal to one-third of the arcs a c d, a c' d, +a c" d, etc. + + * * * * * + + + + +TEST CARD HINTS. + +By Dr. F. OGDEN STOUT. + + +I know it is the custom with a great many if not the majority of +opticians to fit a customer without knowing whether he has presbyopia, +hypermetropia, or any of the other errors of refraction. Their method +is first to try a convex, and if this does not improve, a concave, +etc., until the proper one is found. This, of course, amounts to the +same thing if the right glass is found. But in practice it will be +found both time saving and more satisfactory to first decide with what +error you have to deal. It is very simple, and, where you have no +other means of diagnosing (such as the ophthalmoscope), it does away +with the necessity of trying so many lenses before the proper one is +found. You should have a distance test card placed at a distance of +twenty feet from the person you are examining, and in a good light. + +A distance test card consists of letters of various sizes which it has +been found can be seen at certain distances by people with good +vision. Thus the largest letter is marked with a cc, meaning that this +should be seen at two hundred feet, and another line, XX, at twenty +feet, which is the proper distance for testing vision for distance, +for the reason that a normal eye is at rest when looking at any object +twenty feet from it or beyond, and the rays coming from it are +parallel and come to a focus on the retina. You must also have a near +vision test card with lines that should be seen by a normal eye from +ten to seventy-two inches, and a card of radiating lines for +astigmatism. With this preparation you are ready to proceed. To +illustrate, the first customer comes and tells you that up to six +months ago he had very good vision, but he finds now that, especially +at night, he has trouble in reading or writing, and that he finds he +can see better a little farther away. His head aches and eyes smart. +You will of course say that this is a very simple case. It must be old +sight (presbyopia). Probably it is if he is old enough (45), but you +must prove this for yourself, without asking his age, which is +embarrassing in the case of a lady. If you direct him to the distance +card twenty feet away, and find that he can see every one down to and +including the one marked XX, his vision is up to the standard for +distance, and you know that he can have no astigmatism worth +correcting, nor any near sight, as both of these affect vision for +distance, but he may have far sight or old sight or both combined. You +must find which it is. + +If, while he is still looking at the twenty-foot line, you place in +front of the eyes a weak convex and he tells you he sees just as well +with as without, it proves the existence of far-sight or +hypermetropia, and the strongest convex that still leaves vision as +good for distance as without any, corrects the manifest. But if the +weak convex blurs it, it shows that there is some defect in focusing, +if the near vision is below normal. You therefore know that you have a +case of old sight or presbyopia, requiring the weakest convex to +correct it, that will enable your customer to see the finest line on +the near card at the required distance. + +The next customer that comes to be fitted with glasses can only see +the line marked XL on the distance card at 20 feet or about one-half +of what he should see, which leads you to think that there is no far +sight, for vision for distance is good except in very high degrees of +this error. Nor can there be old-sight, for vision for distance is +good in old-sight until after the fifty-fifth year, but it can be near +sight (myopia) or astigmatism, or both. We next try the near card and +find that even the finest line can be seen clearly if held +sufficiently close to the eyes. We now know that this is a case of +near sight, and we must fit them with glasses for distance. The +weakest concave that will enable him to see the line that should be +seen on the distance card at 20 feet is the proper one to give him for +use.--_The Optician._ + + * * * * * + + + + +CHARLES GOODYEAR. + + +CHARLES GOODYEAR was born in New Haven, December 29, 1800. He was the +son of Amasa Goodyear, and the eldest among six children. His father +was quite proud of being a descendant of Stephen Goodyear, one of the +founders of the colony of New Haven in 1638. + +Amasa Goodyear owned a little farm on the neck of land in New Haven +which is now known as Oyster Point, and it was here that Charles spent +the earliest years of his life. When, however, he was quite young, his +father secured an interest in a patent for the manufacture of ivory +buttons, and looking for a convenient location for a small mill, +settled at Naugatuck, Conn., where he made use of the valuable water +power that is there. Aside from his manufacturing, the elder Goodyear +ran a farm, and between the two lines of industry kept young Charles +pretty busy. + +In 1816, Charles left his home and went to Philadelphia to learn the +hardware business. He worked at this very industriously until he was +twenty-one years old, and then, returning to Connecticut, entered into +partnership with his father at the old stand in Naugatuck, where they +manufactured not only ivory and metal buttons, but a variety of +agricultural implements, which were just beginning to be appreciated +by the farmers. In August of 1824 he was united in marriage with +Clarissa Beecher, a woman of remarkable strength of character and +kindness of disposition, and one who in after years was of the +greatest assistance to the impulsive inventor. Two years later he +removed again to Philadelphia, and there opened a hardware store. His +specialties were the valuable agricultural implements that his firm +had been manufacturing, and after the first distrust of home made +goods had worn away--for all agricultural implements were imported +from England at that time--he found himself established at the head of +a successful business. + +This continued to increase until it seemed but a question of a few +years until he would be a very wealthy man. Between 1829 and 1830 he +suddenly broke down in health, being troubled with dyspepsia. At the +same time came the failure of a number of business houses that +seriously embarrassed his firm. They struggled on, however, for some +time, but were finally obliged to fail. The ten years that followed +this were full of the bitterest struggles and trials to Goodyear. +Under the law that then existed he was imprisoned time after time for +debts, even while he was trying to perfect inventions that should pay +off his indebtedness. + +Between the years 1831 and 1832 he began to hear about gum elastic and +very carefully examined every article that appeared in the newspapers +relative to this new material. The Roxbury Rubber Company, of Boston, +had been for some time experimenting with the gum, and believing that +they had found means for manufacturing goods from it, had a large +plant and were sending their goods all over the country. It was some +of their goods that first attracted his attention. Soon after this +Goodyear visited New York, and went at once to the store of the +Roxbury Rubber Company. While there, he examined with considerable +care some of their life preservers, and it struck him that the tube +used for inflation was not very perfect. He, therefore, on his return +to Philadelphia, made some tubes and brought them down to New York and +showed them to the manager of the Roxbury Rubber Company. + +This gentlemen was so pleased with the ingenuity that Goodyear had +shown in manufacturing these tubes, that he talked very freely with +him and confessed to him that the business was on the verge of ruin, +that the goods had to be tested for a year before they could tell +whether they were perfect or not, and to their surprise, thousands of +dollars worth of goods that they had supposed were all right were +coming back to them, the gum having rotted and made them so offensive +that it was necessary to bury them in the ground to get them out of +the way. + +Goodyear at once made up his mind to experiment on this gum and see if +he could not overcome its stickiness. + +He, therefore, returned to Philadelphia, and, as usual, met a +creditor, who had him arrested and thrown into prison. While there, he +tried his first experiments with India rubber. The gum was very cheap +then, and by heating it and working it in his hands, he managed to +incorporate in it a certain amount of magnesia which produced a +beautiful white compound and appeared to take away the stickiness. + +He therefore thought he had discovered the secret, and through the +kindness of friends was put in the way of further perfecting his +invention at a little place in New Haven. The first thing that he made +here was shoes, and he used his own house for grinding room, calender +room, and vulcanizing department, and his wife and children helped to +make up the goods. His compound at this time was India rubber, +lampblack, and magnesia, the whole dissolved in turpentine and spread +upon the flannel cloth which served as the lining for the shoes. It +was not long, however, before he discovered that the gum, even treated +this way, became sticky, and then those who had supplied the money for +the furtherance of these experiments, completely discouraged, made up +their minds that they could go no further, and so told the inventor. + +[Illustration: CHARLES GOODYEAR.] + +He, however, had no mind to stop here in his experiments, but, selling +his furniture and placing his family in a quiet boarding place, he +went to New York, and there, in an attic, helped by a friendly +druggist, continued his experiments. His next step in this line was to +compound the rubber with magnesia and then boil it in quicklime and +water. This appeared to really solve the problem, and he made some +beautiful goods. At once it was noised abroad that India rubber had +been so treated that it lost its stickiness, and he received medals +and testimonials and seemed on the high road to success, till one day +he noticed that a drop of weak acid, falling on the cloth, neutralized +the alkali, and immediately the rubber was soft again. To see this, +with his knowledge of what rubber should do, proved to him at once +that his process was not a successful one. He therefore continued +experimenting, and after preparing his mixtures in his attic in New +York, would walk three miles to the mill of a Mr. Pike, at Greenwich +village, and there try various experiments. + +In the line of these, he discovered that rubber, dipped in nitric +acid, formed a surface cure, and he made a great many goods with this +acid cure which were spoken of, and which even received a letter of +commendation from Andrew Jackson. + +The constant and varied experiments that Goodyear went through with +affected his health more or less, and at one time he came very near +being suffocated by gas generated in his laboratory. That he did not +die then everybody knows, but he was thrown then into a fever by the +accident and came very near losing his life. + +It was there that he formed an acquaintance with Dr. Bradshaw, who was +very much pleased with the samples of rubber goods that he saw in +Goodyear's room, and when the doctor went to Europe he took them with +him, where they attracted a great deal of attention, but beyond that +nothing was done about them. Now that he appeared to have success, he +found no difficulty in obtaining a partner, and together the two +gentlemen fitted up a factory and began to make clothing, life +preservers, rubber shoes, and a great variety of rubber goods. They +also had a large factory, with special machinery, built at Staten +Island, where he removed his family and again had a home of his own. +Just about this time, when everything looked bright, the great panic +of 1836-1837 came, and swept away the entire fortune of his associate +and left Goodyear without a cent, and no means of earning one. + +His next move was to go to Boston, where he became acquainted with J. +Haskins, of the Roxbury Rubber Company, and found in him a firm +friend, who loaned him money and stood by him when no one would have +anything to do with the visionary inventor. Mr. Chaffee was also +exceedingly kind and ever ready to lend a listening ear to his plans, +and to also assist him in a pecuniary way. It was about this time that +it occurred to Mr. Chaffee that much of the trouble that they had +experienced in working India rubber might come from the solvent that +was used. He therefore invented a huge machine for doing the mixing +by mechanical means. The goods that were made in this way were +beautiful to look at, and it appeared, as it had before, that all +difficulties were overcome. + +Goodyear discovered a new method for making rubber shoes and got a +patent on it, which he sold to the Providence Company, in Rhode +Island. + +The secret of making the rubber so that it would stand heat and cold +and acids, however, had not been discovered, and the goods were +constantly growing sticky and decomposing and being returned. + +In 1838 he, for the first time, met Nathaniel Hayward, who was then +running a factory in Woburn. Some time after this Goodyear himself +moved to Woburn, all the time continuing his experiments. He was very +much interested in Hayward's sulphur experiments for drying rubber, +but it appears that neither of them at that time appreciated the fact +that it needed heat to make the sulphur combine with the rubber and to +vulcanize it. + +The circumstances attending the discovery of his celebrated process is +thus described by Mr. Goodyear himself in his book, "Gum Elastic." It +will be observed that he makes use of the third person in all +references to himself: + + "In the summer of 1838 he became acquainted with Mr. Nathaniel + Hayward, of Woburn, Mass., who had been employed as the foreman of + the Eagle Company at Woburn, where he had made use of sulphur by + impregnating the solvent with it. It was through him that the + writer (Charles Goodyear, who makes use all through his book of + the third person) received the first knowledge of the use of + sulphur as a drier of gum elastic. + + "Mr. Hayward was left in possession of the factory which was + abandoned by the Eagle Company. Soon after this it was occupied by + the writer, who employed him for the purpose of manufacturing life + preservers and other articles by the acid gas process. At this + period he made many novel and useful applications of this + substance. Among other fancy articles he had newspapers printed on + the gum elastic drapery, and the improvement began to be highly + appreciated. He therefore now entered, as he thought, upon a + successful career for the future. A far different result awaited + him. + + "It was supposed by others as well as himself that a change was + wrought through the mass of the goods acted upon by the acid gas, + and that the whole body of the article was made better than the + native gum. The surface of the goods really was so, but owing to + the eventual decomposition of the goods beneath the surface, the + process was pronounced by the public a complete failure. Thus + instead of realizing the large fortune which by all acquainted + with his prospects was considered certain, his whole invention + would not bring him a week's living. + + "He was obliged for the want of means to discontinue + manufacturing, and Mr. Hayward left his employment. The inventor + now applied himself alone, with unabated ardor and diligence, to + detect the cause of his misfortune and if possible to retrieve the + lost reputation of his invention. On one occasion he made some + experiments to ascertain the effect of heat upon the same compound + that had decomposed in the articles previously manufactured, and + was surprised to find that the specimen, being carelessly brought + in contact with a hot stove, charred like leather. He endeavored + to call the attention of his brother as well as some other + individuals who were present, and who were acquainted with the + manufacture of gum elastic, to this effect as remarkable and + unlike any before known, since gum elastic always melted when + exposed to a high degree of heat. The occurrence did not at the + time appear to them to be worthy of notice. It was considered as + one of the frequent appeals that he was in the habit of making in + behalf of some new experiment. He, however, directly inferred that + if the process of charring could be stopped at the right point, it + might divest the gum of its native adhesiveness throughout, which + would make it better than the native gum. + + "He made another trial of heating a similar fabric, before an open + fire. The same effect, that of charring the gum, followed, but + there were further and very satisfactory indications of ultimate + success in producing the desired result, as upon the edge of the + charred portions of the fabric there appeared a line, or border, + that was not charred, but perfectly cured. + + "These facts have been stated precisely as they occurred in + reference to the acid gas, as well as the vulcanizing process. + + "The incidents attending the discovery of both have a strong + resemblance, so much so they may be considered parallel cases. It + being now known that the results of the vulcanizing process are + produced by means and in a manner which would not have been + anticipated from any reasoning on the subject, and that they have + not yet been satisfactorily accounted for, it has been sometimes + asked, how the inventor came to make the discovery? The answer has + already been given. It may be added that he was many years seeking + to accomplish this object, and that he allowed nothing to escape + his notice that related to the subject. Like the falling of an + apple, it was suggestive of an important fact to one whose mind + was previously prepared to draw an inference from any occurrence + which might favor the object of his research. While the inventor + admits that these discoveries were not the results of scientific + chemical investigations, _he is not willing to admit that they + were the result of what is commonly termed accident_; he claims + them to be the result of the closest application and observation. + + "The discoloring and charring of the specimens proved nothing and + discovered nothing of value, but quite the contrary, for in the + first instance, as stated in the acid gas improvement, the + specimen acted upon was thrown away as worthless and left for some + time; in the latter instance, the specimen that was charred was in + like manner disregarded by others. + + "It may, therefore, be considered as one of those cases where the + leading of the Creator providentially aids his creatures, by what + are termed 'accidents,' to attain those things which are not + attainable by the powers of reasoning he has conferred on them." + +Now that Goodyear was sure that he had the key to the intricate puzzle +that he had worked over for so many years, he began at once to tell +his friends about it and to try to secure capital, but they had +listened to their sorrow so many times that his efforts were futile. +For a number of years be struggled and experimented and worked along +in a small way, his family suffering with himself the pangs of the +extremest poverty. At last he went to New York and showed some of his +samples to William Ryder, who, with his brother Emory, at once +appreciated the value of the discovery and started in to +manufacturing. Even here Goodyear's bad luck seemed to follow him, for +the Ryder Bros. failed and it was impossible to continue the business. + +He had, however, started a small factory at Springfield, Mass., and +his brother-in-law, Mr. De Forest, who was a wealthy woolen +manufacturer, took Ryder's place, and the work of making the invention +practical was continued. In 1844 it was so far perfected that Goodyear +felt it safe to take out a patent. The factory at Springfield was run +by his brothers, Nelson and Henry. + +In 1843 Henry started one in Naugatuck, and in 1844 introduced +mechanical mixing in place of the mixture by the use of solvents. + +In the year 1852 Goodyear went to Europe, a trip that he had long +planned, and saw Hancock, then in the employ of Charles Macintosh & +Co. Hancock admitted in evidence that the first piece of vulcanized +rubber he ever saw came from America, but claimed to have reinvented +vulcanization and secured patents in Great Britain, but it is _a +remarkable fact_ that Charles Goodyear's French patent was the first +publication in Europe of this discovery. + +In 1852 a French company were licensed by Mr. Goodyear to make shoes, +and a great deal of interest was felt in the new business. In 1855 the +French emperor gave to Charles Goodyear the grand medal of honor and +decorated him with the cross of the legion of honor in recognition of +his services as a public benefactor, but the French courts +subsequently set aside his French patents on the ground of the +importation of vulcanized goods from America by licenses under the +United States patents. He died July 1, 1860, at the Fifth Avenue +Hotel, New York City.--_India Rubber World_. + + * * * * * + +[Continued from SUPPLEMENT, No. 786, page 12558.] + + + + +THE ELECTROMAGNET. + +[Footnote: Lectures delivered before the Society of Arts, London, +1890. From the Journal of the Society.] + +BY PROFESSOR SILVANUS P. THOMPSON, D. SC., B.A., M.I.E.E. + +III. + +RESEARCHES OF PROFESSOR HUGHES. + + +[Illustration: FIG. 51.--HUGHES' ELECTROMAGNET.] + +His object was to find out the best form of electromagnet, the best +distance between the poles, and the best form of armature for the +rapid work required in Hughes' printing telegraphs. One word about +Hughes' magnets. This diagram (Fig. 51) shows the form of the well +known Hughes' electromagnet. I feel almost ashamed to say those words +"well known," because on the Continent everybody knows what you mean +by a Hughes' electromagnet. In England scarcely anyone knows what you +mean. Englishmen do not even know that Professor Hughes has invented a +special form of electromagnet. Hughes' special form is this: A +permanent steel magnet, generally a compound one, having soft iron +pole pieces, and a couple of coils on the pole pieces only. As I have +to speak of Hughes' special contrivance among the mechanisms that will +occupy our attention later on, I only now refer to this magnet in one +particular. If you wish a magnet to work rapidly, you will secure the +most rapid action, not when the coils are distributed all along, but +when they are heaped up near, not necessarily entirely on, the poles. +Hughes made a number of researches to find out what the right length +and thickness of these pole pieces should be. It was found an +advantage not to use too thin pole pieces, otherwise the magnetism +from the permanent magnet did not pass through the iron without +considerable reluctance, being choked by insufficiency of section: +also not to use too thick pieces, otherwise they presented too much +surface for leakage across from one to the other. Eventually a +particular length was settled upon, in proportion about six times the +diameter, or rather longer. In the further researches that Hughes made +he used a magnet of shorter form, not shown here, more like those +employed in relays, and with an armature from 2 to 3 millimeters +thick, 1 centimeter wide and 5 centimeters long. The poles were turned +over at the top toward one another. Hughes tried whether there was any +advantage in making those poles approach one another, and whether +there was any advantage in having as long an armature as 5 +centimeters. He tried all the different kinds, and plotted out the +results of observations in curves, which could be compared and +studied. His object was to ascertain the conditions which would give +the strongest pull, not with a steady current, but with such currents +as were required for operating his printing telegraph instruments; +currents which lasted but one to twenty hundredths of a second. He +found it was decidedly an advantage to shorten the length of the +armature, so that it did not protrude far over the poles. In fact, he +got a sufficient magnetic circuit to secure all the attractive power +that he needed, without allowing as much chance of leakage as there +would have been had the armature extended a longer distance over the +poles. He also tried various forms of armature having very various +cross sections. + + +POSITION AND FORM OF ARMATURE. + +In one of Du Moncel's papers on electromagnets[1] you will also find a +discussion on armatures, and the best forms for working in different +positions. Among other things in Du Moncel you will find this paradox: +that whereas using a horseshoe magnet with fat poles, and a flat piece +of soft iron for armature, it sticks on far tighter when put on +edgeways; on the other hand, if you are going to work at a distance, +across air, the attraction is far greater when it is set flatways. I +explained the advantage of narrowing the surfaces of contact by the +law of traction, B², coming in. Why should we have for action at a +distance the greater advantage from placing the armature flatway to +the poles? It is simply that you thereby reduce the reluctance offered +by the air gap to the flow of the magnetic lines. Du Moncel also tried +the difference between round armatures and flat ones, and found that a +cylindrical armature was only attracted about half as strongly as a +prismatic armature having the same surface when at the same distance. +Let us examine this fact in the light of the magnetic circuit. The +poles are flat. You have at a certain distance away a round armature; +there is a certain distance between its nearest side and the polar +surfaces. If you have at the same distance away a flat armature having +the same surface, and, therefore, about the same tendency to leak, why +do you get a greater pull in this case than in that? I think it is +clear that if they are at the same distance away, giving the same +range of motion, there is a greater magnetic reluctance in the case of +the round armature, although there is the same periphery, because, +though the nearest part of the surface is at the prescribed distance, +the rest of the under surface is farther away; so that the gain found +in substituting an armature with a flat surface is a gain resulting +from the diminution in the resistance offered by the air gap. + +[Footnote 1: "La Lumiere Electrique," vol. ii.] + + +POLE PIECES ON HORSESHOE MAGNETS. + +Another of Du Moncel's researches[2] relates to the effect of polar +projections or shoes--movable pole pieces, if you like--upon a +horseshoe electromagnet. The core of this magnet was of round iron 4 +centimeters in diameter, and the parallel limbs were 10 centimeters +long and 6 centimeters apart. The shoes consisted of two flat pieces +of iron slotted out at one end, so that they could be slid along over +the poles and brought nearer together. The attraction exerted on a +flat armature across air gaps 2 millimeters thick was measured by +counterpoising. Exciting this electromagnet with a certain battery, it +was found that the attraction was greatest when the shoes were pushed +to about 15 millimeters, or about one-quarter of the interpolar +distance, apart. The numbers were as follows: + + Distance between + shoes. Attraction, + Millimeters. in grammes. + + 2 900 + 10 1,012 + 15 1,025 + 25 965 + 40 890 + 60 550 + +[Footnote 2: "La Lumiere Electrique," vol. iv., p. 129.] + +With a stronger battery the magnet without shoes had an attraction of +885 grammes, but with the shoes 15 millimeters apart, 1,195 grammes. +When one pole only was employed, the attraction, which was 88 grammes +without a shoe, was _diminished_ by adding a shoe to 39 grammes! + + +CONTRAST BETWEEN ELECTROMAGNETS AND PERMANENT MAGNETS. + +Now I want particularly to ask you to guard against the idea that all +these results obtained from electromagnets are equally applicable to +permanent magnets of steel; they are not, for this simple reason. With +an electromagnet, when you put the armature near, and make the +magnetic circuit better, you not only get more magnetic lines going +through that armature, but you get more magnetic lines going through +the whole of the iron. You get more magnetic lines round the bend when +you put an armature on to the poles, because you have a magnetic +circuit of less reluctance with the same external magnetizing power in +the coils acting around it. Therefore, in that case, you will have a +greater magnetic flux all the way round. The data obtained with the +electromagnet (Fig. 42), with the exploring coil, C, on the bend of +the core, where the armature was in contact, and when it was removed +are most significant. When the armature was present it multiplied the +total magnetic flow tenfold for weak currents and nearly threefold for +strong currents. But with a steel horseshoe, magnetized once for all, +the magnetic lines that flow around the bend of the steel are a fixed +quantity, and, however much you diminish the reluctance of the +magnetic circuit, you do not create or evoke any more. When the +armature is away the magnetic lines arch across, not at the ends of +the horseshoe only, but from its flanks; the whole of the magnetic +lines leaking somehow across the space. Where you have put the +armature on, these lines, instead of arching out into space as freely +as they did, pass for the most part along the steel limbs and through +the iron armature. You may still have a considerable amount of +leakage, but you have not made one line more go through the bent part. +You have absolutely the same number going through the bend with the +armature off as with the armature on. You do not add to the total +number by reducing the magnetic reluctance, because you are not +working under the influence of a constantly impressed magnetizing +force. By putting the armature on to a steel horseshoe magnet you +only _collect_ the magnetic lines, you do not _multiply_ them. This is +not a matter of conjecture. A group of my students have been making +experiments in the following way: They took this large steel horseshoe +magnet (Fig. 52), the length of which, from end to end, through the +steel, is 42½ inches. A light, narrow frame was constructed so that it +could be slipped on over the magnet, and on it were wound 30 turns of +fine wire, to serve as an exploring coil. The ends of this coil were +carried to a distant part of the laboratory, and connected to a +sensitive ballistic galvanometer. The mode of experimenting is as +follows: + +The coil is slipped on over the magnet (or over its armature) to any +desired position. The armature of the magnet is placed gently upon the +poles, and time enough is allowed to elapse for the galvanometer +needle to settle to zero. The armature is then suddenly detached. The +first swing measures the change, due to removing the armature, in the +number of magnetic lines that pass through the coil in the particular +position. + +[Illustration: FIG. 52.--EXPERIMENT WITH PERMANENT MAGNET.] + +I will roughly repeat the experiment before you: The spot of light on +the screen is reflected from my galvanometer at the far end of the +table. I place the exploring coil just over the pole, and slide on the +armature; then close the galvanometer circuit. Now I detach the +armature, and you observe the large swing. I shift the exploring coil, +right up to the bend; replace the armature; wait until the spot of +light is brought to rest at the zero of the scale. Now, on detaching +the armature, the movement of the spot of light is quite +imperceptible. In our careful laboratory experiments, the effect was +noticed inch by inch all along the magnet. The effect when the +exploring coil was over the bend was not as great as 1-3000th part of +the effect when the coil was hard up to the pole. We are, therefore, +justified in saying that the number of magnetic lines in a permanently +magnetized steel horseshoe magnet is not altered by the presence or +absence of the armature. + +You will have noticed that I always put on the armature gently. It +does not do to slam on the armature; every time you do so, you knock +some of the so-called permanent magnetism out of it. But you may pull +off the armature as suddenly as you like. It does the magnet good +rather than harm. There is a popular superstition that you ought never +to pull off the keeper of a magnet suddenly. On investigation, it is +found that the facts are just the other way. You may pull off the +keeper as suddenly as you like, but you should never slam it on. + +From these experimental results I pass to the special design of +electromagnets for special purposes. + + +ELECTROMAGNETS FOR MAXIMUM TRACTION. + +These have already been dealt with in the preceding lecture; the +characteristic feature of all the forms suitable for traction being +the compact magnetic circuit. + +Several times it has been proposed to increase the power of +electromagnets by constructing them with intermediate masses of iron +between the central core and the outside, between the layers of +windings. All these constructions are founded on fallacies. Such iron +is far better placed either right inside the coils or right outside +them, so that it may properly constitute a part of the magnetic +circuit. The constructions known as Camacho's and Cance's, and one +patented by Mr. S.A. Varley, in 1877, belonging to this delusive order +of ideas, are now entirely obsolete. + +Another construction which is periodically brought forward as a +novelty is the use of iron windings of wire or strip in place of +copper winding. The lower electric conductivity of iron, as compared +with copper, makes such a construction wasteful of exciting power. To +apply equal magnetizing power by means of an iron coil implies the +expenditure of about six times as many watts as need be expended if +the coil is of copper. + + +ELECTROMAGNETS FOR MAXIMUM RANGE OF ATTRACTION. + +We have already laid down the principle which will enable us to design +electromagnets to act at a distance. We want our magnet to project, as +it were, its force across the greatest length of air gap. Clearly, +then, such a magnet must have a very large magnetizing power, with +many ampere turns upon it, to be able to make the required number of +magnetic lines pass across the air resistance. Also it is clear that +the poles must not be too close together for its work, otherwise the +magnetic lines at one pole will be likely to curl round and take short +cuts to the other pole. There must be a wider width between the poles +than is desirable in electromagnets for traction. + + +ELECTROMAGNETS OF MINIMUM WEIGHT. + +In designing an apparatus to put on board a boat or a balloon, where +weight is a consideration of primary importance, there is again a +difference. There are three things that come into play--iron, copper, +and electric current. The current weighs nothing, therefore, if you +are going to sacrifice everything else to weight, you may have +comparatively little iron, but you must have enough copper to be able +to carry the electric current; and under such circumstances you must +not mind heating your wires nearly red hot to pass the biggest +possible current. Provide as little copper as you conveniently can, +sacrificing economy in that case to the attainment of your object; +but, of course, you must use fireproof material, such as asbestos, for +insulating, instead of cotton or silk. + + +A USEFUL GUIDING PRINCIPLE. + +In all cases of design there is one leading principle which will be +found of great assistance, namely, that a magnet always tends so to +act as though it tried to diminish the length of its magnetic circuit. +It tries to grow more compact. This is the reverse of that which holds +good with an electric current. The electric circuit always tries to +enlarge itself, so as to inclose as much space as possible, but the +magnetic circuit always tries to make itself as compact as possible. +Armatures are drawn in as near as can be, to close up the magnetic +circuit. Many two-pole electromagnets show a tendency to bend together +when the current is turned on. One form in particular, which was +devised by Ruhmkorff for the purpose of repeating Faraday's celebrated +experiment on the magnetic rotation of polarized light, is liable to +this defect. Indeed, this form of electromagnet is often designed very +badly, the yoke being too thin, both mechanically and magnetically, +for the purpose which it has to fulfill. + +Here is a small electric bell, constructed by Wagener, of Wiesbaden, +the construction of which illustrates this principle. The +electromagnet, a horseshoe, lies horizontally; its poles are provided +with protruding curved pins of brass. Through the armature are drilled +two holes, so that it can be hung upon the two brass pins; and when so +hung up it touches the ends of the iron cores just at one edge, being +held from more perfect contact by a spring. There is no complete gap, +therefore, in the magnetic circuit. When the current comes and applies +a magnetizing power, it finds the magnetic circuit already complete in +the sense that there are no absolute gaps. But the circuit can be +bettered by tilting the armature to bring it flat against the polar +ends, that being indeed the mode of motion. This is a most reliable +and sensitive pattern of bell. + +[Illustration: FIG. 53.--ELECTROMAGNETIC POP-GUN.] + +_Electromagnetic Pop-gun._--Here is another curious illustration of +the tendency to complete the magnetic circuit. Here is a tubular +electromagnet (Fig. 53), consisting of a small bobbin, the core of +which is an iron tube about two inches long. There is nothing very +unusual about it; it will stick on, as you see, to pieces of iron when +the current is turned on. It clearly is an ordinary electromagnet in +that respect. Now suppose I take a little round rod of iron, about an +inch long, and put it into the end of the tube, what will happen when +I turn on my current? In this apparatus as it stands, the magnetic +circuit consists of a short length of iron, and then all the rest is +air. The magnetic circuit will try to complete itself, not by +shortening the iron, but by _lengthening_ it; by pushing the piece of +iron out so as to afford more surface for leakage. That is exactly +what happens; for, as you see, when I turn on the current, the little +piece of iron shoots out and drops down. You see that little piece of +iron shoot out with considerable force. It becomes a sort of magnetic +popgun. This is an experiment which has been twice discovered. I found +it first described by Count Du Moncel, in the pages of _La Lumiere +Electrique_, under the name of the "pistolet electromagnetique;" and +Mr. Shelford Bidwell invented it independently. I am indebted to him +for the use of this apparatus. He gave an account of it to the +Physical Society, in 1885, but the reporter missed it, I suppose, as +there is no record in the society's proceedings. + + +ELECTROMAGNETS FOR USE WITH ALTERNATING CURRENTS. + +When you are designing electromagnets for use with alternating +currents, it is necessary to make a change in one respect, namely, you +must so laminate the iron that internal eddy currents shall not occur; +indeed, for all rapid-acting electromagnetic apparatus it is a good +rule that the iron must not be solid. It is not usual with telegraphic +instruments to laminate them by making up the core of bundles of iron +plates or wires, but they are often made with tubular cores, that is +to say, the cylindrical iron core is drilled with a hole down the +middle, and the tube so formed is slit with a saw cut to prevent the +circulation of currents in the substance of the tube. Now when +electromagnets are to be employed with rapidly alternating currents, +such as are used for electric lighting, the frequency of the +alternations being usually about 100 periods per second, slitting the +cores is insufficient to guard against eddy currents; nothing short of +completely laminating the cores is a satisfactory remedy. I have here, +thanks to the Brush Electric Engineering Company, an electromagnet of +the special form that is used in the Brush arc lamp when required for +the purpose of working in an alternating current circuit. It has two +bobbins that are screwed up against the top of an iron box at the head +of the lamp. The iron slab serves as a kind of yoke to carry the +magnetism across the top. There are no fixed cores In the bobbins, +which are entered by the ends of a pair of yoked plungers. Now in the +ordinary Brush lamp for use with a steady current, the plungers are +simply two round pieces of iron tapped into a common yoke; but for +alternate current working this construction must not be used, and +instead a U-shaped double plunger is used, made up of laminated iron, +riveted together. Of course it is no novelty to use a laminated core; +that device, first used by Joule, and then by Cowper, has been +repatented rather too often during the past fifty years to be +considered as a recent invention. + +The alternate rapid reversals of the magnetism in the magnetic field +of an electromagnet, when excited by alternating electric currents, +sets up eddy currents in every piece of undivided metal within range. +All frames, bobbin tubes, bobbin ends, and the like, must be most +carefully slit, otherwise they will overheat. If a domestic flat iron +is placed on the top of the poles of a properly laminated +electromagnet, supplied with alternating currents, the flat iron is +speedily heated up by the eddy currents that are generated internally +within it. The eddy currents set up by induction in neighboring masses +of metal, especially in good conducting metals such as copper, give +rise to many curious phenomena. For example, a copper disk or copper +ring placed over the pole of a straight electromagnet so excited is +violently repelled. These remarkable phenomena have been recently +investigated by Professor Elihu Thomson, with whose beautiful and +elaborate researches we have lately been made conversant in the pages +of the technical journals. He rightly attributes many of the repulsion +phenomena to the lag in phase of the alternating currents thus induced +in the conducting metal. The electromagnetic inertia, or +self-inductive property of the electric circuit, causes the currents +to rise and fall later in time than the electromotive forces by which +they are occasioned. In all such cases the impedance which the circuit +offers is made up of two things--resistance and inductance. Both these +causes tend to diminish the amount of current that flows, and the +inductance also tends to delay the flow. + + +ELECTROMAGNETS FOR QUICKEST ACTION. + +I have already mentioned Hughes' researches on the form of +electromagnet best adapted for rapid signaling. I have also +incidentally mentioned the fact that where rapidly varying currents +are employed, the strength of the electric current that a given +battery can yield is determined not so much by the resistance of the +electric circuit as by its electric inertia. It is not a very easy +task to explain precisely what happens to an electric circuit when the +current is turned on suddenly. The current does not suddenly rise to +its full value, being retarded by inertia. The ordinary law of Ohm in +its simple form no longer applies; one needs to apply that other law +which bears the name of the law of Helmholtz, the use of which is to +give us an expression, not for the final value of the current, but for +its value at any short time, t, after the current has been turned on. +The strength of the current after a lapse of a short time, t, cannot +be calculated by the simple process of taking the electromotive force +and dividing it by the resistance, as you would calculate steady +currents. + +In symbols, Helmholtz's law is: + + i_{t} = E/R ( 1 - e^{-(R/L)t} ) + +In this formula i_{t} means the strength of the current after the +lapse of a short time t; E is the electromotive force; R, the +resistance of the whole circuit; L, its coefficient of self-induction; +and _e_ the number 2.7183, which is the base of the Napierian +logarithms. Let us look at this formula; in its general form it +resembles Ohm's law, but with a new factor, namely, the expression +contained within the brackets. The factor is necessarily a fractional +quantity, for it consists of unity less a certain negative +exponential, which we will presently further consider. If the factor +within brackets is a quantity less than unity, that signifies that +i_{t} will be less than E ÷ R. Now the exponential of negative sign, +and with negative fractional index, is rather a troublesome thing to +deal with in a popular lecture. Our best way is to calculate some +values, and then plot it out as a curve. When once you have got it +into the form of a curve, you can begin to think about it, for the +curve gives you a mental picture of the facts that the long formula +expresses in the abstract. Accordingly we will take the following +case. Let E = 2 volts; R = 1 ohm; and let us take a relatively large +self-induction, so as to exaggerate the effect; say let L = 10 quads. +This gives us the following: + + ________________________________________ + | | | | + | t_{(sec.)} | e^{+(R/L)t} | i_{t} | + --------------+--------------+---------| + | 0 | 1 | 0 | + | 1 | 1.105 | 0.950 | + | 2 | 1.221 | 1.810 | + | 5 | 1.649 | 3.936 | + | 10 | 2.718 | 6.343 | + | 20 | 7.389 | 8.646 | + | 30 | 20.08 | 9.501 | + | 60 | 403.4 | 9.975 | + | 120 | 16200.0 | 9.999 | + ---------------------------------------- + +In this case the value of the steady current as calculated by Ohm's +law is 10 amperes, but Helmholtz's law shows us that with the great +self-induction which we have assumed to be present, the current, even +at the end of 30 seconds, has only risen up to within 5 percent. of +its final value; and only at the end of two minutes has practically +attained full strength. These values are set out in the highest curve +in Fig. 54, in which, however, the further supposition is made that +the number of spirals, S, in the coils of the electromagnet is 100, so +that when the current attains its full value of 10 amperes, the full +magnetizing power will be Si = 1000. It will be noticed that the +curve rises from zero at first steeply and nearly in a straight line, +then bends over, and then becomes nearly straight again, as it +gradually rises to its limiting value. The first part of the +curve--that relating to the strength of the current after _very small_ +interval of time--is the period within which the strength of the +current is governed by inertia (i.e., the self-induction) rather than +by resistance. In reality the current is not governed either by the +self-induction or by the resistance alone, but by the ratio of the +two. This ratio is sometimes called the "time constant" of the +circuit, for it represents _the time_ which the current takes in that +circuit to rise to a definite fraction of its final value. + + E = 10 + r = 1 + R = 100 + L = 10 + + Si + 1000 + _..------------------------------- + | . _ _--------- + | . .---- + | . .- 2 IN SERIES + | . .- + | - + | .: - : + | .: . : + 500 | . : __- -:--------------------------- + | . : _.- - : 2 IN PARALLEL + | . :. - : + | . / : - : + | . / - : + |. / - : : + |./. : : + |/_____:_____________:____________________________ t + 10 20 40 60 80 100 120 + + FIG. 54.--CURVES OF RISE OF CURRENTS. + +This definite fraction is the fraction (e - 1)/e; or in decimals, +0.634. All curves of rise of current are alike in general shape, they +differ only in scale, that is to say, they differ only in the height +to which they will ultimately rise, and in the time they will take to +attain this fraction of their final value. + +_Example (1)._--Suppose E = 10; R = 200 ohms; L = 8. The final value +of the current will be 0.025 amp. or 25 milliamperes. Then the time +constant will be 8 ÷ 400 = 1-50th sec. + +_Example (2)._--The P.O. Standard "A" relay has R = 400 ohms; L = +3.25. It works with 0.5 milliampere current, and therefore will work +with 5 Daniell cells through a line of 9,600 ohms. Under these +circumstances the time constant of the instrument on short circuit is +0.0081 sec. + +It will be noted that the time constant of a circuit can be reduced +either by diminishing the self-induction or by increasing the +resistance. In Fig. 54 the position of the time constant for the top +curve is shown by the vertical dotted line at 10 seconds. The current +will take 10 seconds to rise to 0.634 of its final value. This +retardation of the rise of current is simply due to the presence of +coils and electromagnets in the circuit; the current as it grows being +retarded because it has to create magnetic fields in these coils, and +so sets up opposing electromotive forces that prevent it from growing +all at once to its full strength. Many electricians, unacquainted with +Helmholtz's law, have been in the habit of accounting for this by +saying that there is a lag in the iron of the electromagnet cores. +They tell you that an iron core cannot be magnetized suddenly, that it +takes time to acquire its magnetism. They think it is one of the +properties of iron. But we know that the only true time lag in the +magnetization of iron, that which is properly termed "viscous +hysteresis," does not amount to any great percentage of the whole +amount of magnetization, takes comparatively a long time to show +itself, and cannot therefore be the cause of the retardation which we +are considering. There are also electricians who will tell you that +when magnetization is suddenly evoked in an iron bar, there are +induction currents set up in the iron which oppose and delay its +magnetization. That they oppose the magnetization is perfectly true, +but if you carefully laminate the iron so as to eliminate eddy +currents, you will find, strangely enough, that the magnetism rises +still more slowly to its final value. For by laminating the iron you +have virtually increased the self-inductive action, and increased the +time constant of the circuit, so that the currents rise more slowly +than before. The lag is not in the iron, but in the magnetizing +current, and the current being retarded, the magnetization is of +course retarded also. + + +CONNECTING COILS FOR QUICKEST ACTION. + +Now let us apply these most important though rather intricate +considerations to the practical problems of the quick working of the +electromagnet. Take the case of an electromagnet forming some part of +the receiving apparatus of a telegraph system in which it is desired +to secure very rapid working. Suppose the two coils that are wound +upon the horseshoe core are connected together in series. The +coefficient of self-induction for these two is four times as great as +that of either separately; coefficients of self-induction being +proportional to the square of the number of turns of wire that +surround a given core. Now if the two coils instead of being put in +series are put in parallel, the coefficient of self-induction will be +reduced to the same value as if there were only one coil, because half +the line current (which is practically unaltered) will go through each +coil. Hence the time constant of the circuit when the coils are in +parallel will be a quarter of that which it is when the coils are in +series; on the other hand, for a given line current, the final +magnetizing power of the two coils in parallel is only half what it +would be with the coil in series. The two lower curves in Fig. 54 +illustrate this, from which it is at once plain that the magnetizing +power for very brief currents is greater when the two coils are put in +parallel with one another than when they are joined in series. + +Now this circumstance has been known for some time to telegraph +engineers. It has been patented several times over. It has formed the +theme of scientific papers, which have been read both in France and in +England. The explanation generally given of the advantage of uniting +the coils in parallel is, I think, fallacious; namely that the "extra +currents" (i.e., currents due to self-induction) set up in the two +coils are induced in such directions as tend to help one another when +the coils are in series, and to neutralize one another when they are +in parallel. It is a fallacy, because in neither case do they +neutralize one another. Whichever way the current flows to make the +magnetism, it is opposed in the coils while the current is rising, +and helped in the coils while the current is falling, by the so-called +extra currents. If the current is rising in both coils at the same +moment, then, whether the coils are in series or in parallel, the +effect of self-induction is to retard the rise of the current. The +advantage of parallel grouping is simply that it reduces the time +constant. + + +BATTERY GROUPING FOR QUICKEST ACTION. + +One may consider the question of grouping the battery cells from the +same point of view. How does the need for rapid working, and the +question of time constant, affect the best mode of grouping the +battery cells? The amateur's rule, which tells you to so arrange your +battery that its internal resistance should be equal to the external +resistance, gives you a result wholly wrong for rapid working. The +supposed best arrangement will not give you (at the expense even of +economy) the best result that might be got out of the given number of +cells. Let us take an example and calculate it out, and place the +results graphically before our eyes in the form of curves. Suppose the +line and electromagnet have together a resistance of 6 ohms, and that +we have 24 small Daniell cells, each of electromotive force say 1 volt, +and of internal resistance 4 ohms. Also let the coefficient of +self-induction of the electromagnet and circuit be 6 quadrants. When +all the cells are in series, the resistance of the battery will be 96 +ohms, the total resistance of the circuit 102 ohms, and the full value +of the current 0.235 ampere. When all the cells are in parallel, the +resistance of the battery will be 0.133 ohm, the total resistance +6.133 ohms, and the full value of the current 0.162 ampere. According +to the amateur rule of grouping cells so that internal resistance +equals external, we must arrange the cells in 4 parallels, each having +6 cells in series, so that the internal resistance of the battery will +be 6 ohms, total resistance of circuit 12 ohms, full value of current +0.5 ampere. Now the corresponding time constants of the circuit in the +three cases (calculated by dividing the coefficient of self-induction +by the total resistance) will be respectively--in series, 0.06 sec.; +in parallel, 0.5 sec.; grouped for maximum steady current, 0.96 sec. +From these data we may now draw the three curves, as in Fig. 55, +wherein the abscissæ are the values of time in seconds and the +ordinates the current. The faint vertical dotted lines mark the time +constants in the three cases. It will be seen that when rapid working +is required the magnetizing current will rise, during short intervals +of time, more rapidly if all the cells are put in series than it will +do if the cells are grouped according to the amateur rule. + + | + 5| . + | . + | . + 4| MAXIMUM . + | OUTPUT \ . + | . + 3| . + | . : ALL IN SERIES + | _-------------------:------------------------------ + 2| .- - : + | - - : + | -: - : + 1| / : - : ALL IN PARALLEL + |. : . : _________-------- + |- :__ : ---------- + +-----------------------------:------------------------------- + 0 1 2 3 4 5 6 7 8 9 10 + +FIG. 55.--CURVES OF RISE OF CURRENT WITH DIFFERENT GROUPINGS OF BATTERY. + +When they are all put in series, so that the battery has a much +greater resistance than the rest of the circuit, the current rises +much more rapidly, because of the smallness of the time constant, +although it never attains the same ultimate maximum as when grouped in +the other way. That is to say, if there is self-induction as well as +resistance in the circuit, the amateur rule does not tell you the best +way of arranging the battery. There is another mode of regarding the +matter which is helpful. Self-induction, while the current is growing, +acts as if there were a sort of spurious addition to the resistance of +the circuit; and while the current is dying away it acts of course in +the other way, as if there were a subtraction from the resistance. +Therefore you ought to arrange the battery so that the internal +resistance is equal to the real resistance of the circuit, plus the +spurious resistance during that time. But how much is the spurious +resistance during that time? It is a resistance proportional to the +time that has elapsed since the current was turned on. So then it +comes to a question of the length of time for which you want to work +it. What fraction of a second do you require your signal to be given +in? What is the rate of the vibrator of your electric bell? Suppose +you have settled that point, and that the short time during which the +current is required to rise is called t; then the apparent resistance +at time t after the current is turned on is given by the formula: + + R_{t} = R × e^{(R/L)t} + ( e^{(R/L)t} - 1 ) + + +TIME CONSTANTS OF ELECTROMAGNETS. + +I may here refer to some determinations made by M. Vaschy,[1] +respecting the coefficients of self-induction of the electromagnets of +a number of pieces of telegraphic apparatus. Of these I must only +quote one result, which is very significant. It relates to the +electromagnet of a Morse receiver of the pattern habitually used on +the French telegraph lines. + + L, in quadrants. + Bobbins, separately, without iron cores. 0.233 and 0.265 + Bobbins, separately, with iron cores. 1.65 and 1.71 + Bobbins, with cores joined by yoke, + coils in series 6.37 + Bobbins, with armature resting on poles. 10.68 + +[Footnote 1: "Bulletin de la Societe Internationale des Electriciens," +1886.] + +It is interesting to note how the perfecting of the magnetic circuit +increases the self-induction. + +Thanks to the kindness of Mr. Preece, I have been furnished with some +most valuable information about the coefficients of self-induction, +and the resistance of the standard pattern of relays, and other +instruments which are used in the British postal telegraph service, +from which data one is able to say exactly what the time constants of +those instruments will be on a given circuit, and how long in their +case the current will take to rise to any given fraction of its final +value. Here let me refer to a very capital paper by Mr. Preece in an +old number of the "Journal of the Society of Telegraph Engineers," a +paper "On Shunts," in which he treats this question, not as perfectly +as it could now be treated with the fuller knowledge we have in 1890 +about the coefficients of self-induction, but in a very useful and +practical way. He showed most completely that the more perfect the +magnetic circuit is--though of course you are getting more magnetism +from your current--the more is that current retarded. Mr. Preece'e +mode of experiment was extremely simple. He observed the throw of the +galvanometer when the circuit which contained the battery and the +electromagnet was opened by a key which at the same moment connected +the electromagnet wires to the galvanometer. The throw of the +galvanometer was assumed to represent the extra current which flowed +out. Fig. 56 represents a few of the results of Mr. Preece's paper. + + +==========+ + |=| |=| |=| |=| |=| + \======= \======= =======/ ======= ======= + | | | | | | | | | | + | | | | | | | | | | + | | | |--| | | | | | + ======= ======= ======= /======= =======\ + |=| |=| |=| |=| |=| + + +===========+ +==========+ +===== ======+ + |=| |=| |=| |=| |=| |=| + ======= =======/ B\======= =======/A A\======= =======/B + | | | | | | | | | | | | + | | | | | | | | | | | | + | |--| | | | | | | | | | + ======= ======= A======= =======B =======B =======A + |=| |=| |=| |=| |=| |=| + +==========+ +==========+ +====== =====+ + + FIG. 56.--ELECTROMAGNETS OF RELAY, AND THEIR EFFECTS. + +Take from an ordinary relay a coil, with its iron core, half the +electromagnet, so to speak, without any yoke or armature. Connect it +up as described, and observe the throw given to the galvanometer. The +amount of throw obtained from the single coil was taken as unity, and +all others were compared with it. If you join up two such coils as +they are usually joined, in series, but without any iron yoke across +the cores, the throw was 17. Putting the iron yoke across the cores, +to constitute a horseshoe form, 496 was the throw; that is to say, the +tendency of this electromagnet to retard the current was 496 times as +great as that of the simple coil. But when an armature was put over +the top, the effect ran up to 2,238. By the mere device of putting the +coils in parallel, instead of in series, the 2,238 came down to 502, a +little less than the quarter value which would have been expected. +Lastly, when the armature and yoke were both of them split in the +middle, as is done in fact in all the standard patterns of the British +postal telegraph relays, the throw of the galvanometer was brought +down from 502 to 26. Relays so constructed will work excessively +rapidly. Mr. Preece states that with the old pattern of relay having +so much self-induction as to give a galvanometer throw of 1,688, the +speed of signaling was only from 50 to 60 words per minute, whereas, +with the standard relays constructed on the new plan, the speed of +signaling is from 400 to 450 words per minute. It is a very +interesting and beautiful result to arrive at from the experimental +study of these magnetic circuits. + + +SHORT CORES _versus_ LONG CORES. + +In considering the forms that are best for rapid action, it ought to +be mentioned that the effects of hysteresis in retarding changes in +the magnetization of iron cores are much more noticeable in the case +of nearly closed magnetic circuits than in short pieces. +Electromagnets with iron armatures in contact across their poles will +retain, after the current has been cut off, a very large part of their +magnetism, even if the cores be of the softest of iron. But so soon as +the armature is wrenched off, the magnetism disappears. An air gap in +a magnetic circuit always tends to hasten demagnetizing. A magnetic +circuit composed of a long air path and a short iron path demagnetizes +itself much more rapidly than one composed of a short air path and a +long iron path. In long pieces of iron the mutual action of the +various parts tends to keep in them any magnetization that they may +possess; hence they are less readily demagnetized. In short pieces, +where these mutual actions are feeble or almost absent, the +magnetization is less stable, and disappears almost instantly on the +cessation of the magnetizing force. Short bits and small spheres of +iron have no magnetic memory. Hence the cause of the commonly received +opinion among telegraph engineers that for rapid work electromagnets +must have short cores. As we have seen, the only reason for employing +long cores is to afford the requisite length for winding the wire +which is necessary for carrying the needful circulation of current to +force the magnetism across the air gaps. If, for the sake of rapidity +of action, length has to be sacrificed, then the coils must be heaped +up more thickly on the short cores. The electromagnets in American +patterns of telegraphic apparatus usually have shorter cores, and a +relatively greater thickness of winding upon them, than those of +European patterns. + + * * * * * + + + + +ELECTRIC ERYGMASCOPE. + + +The erygmascope is the name of an electric lighting apparatus designed +for the examination of the strata of earth traversed by boring +apparatus. + +It consists of a very powerful incandescent lamp inclosed in a +metallic cylinder. One of the two semi-cylindrical sides constitutes +the reflector, and the other, which is of thick glass, allows of the +passage of the luminous rays, which thus illuminate with great +brilliancy the strata of earth traversed by the instrument. The base, +which is inclined at an angle of 45°, is an elliptical mirror, and the +top, of straight section, is open in order to permit the observer +standing at the mouth of the well, and provided with a powerful +spyglass, to see in the mirror the image of the earth. The lamp is so +mounted that its upwardly emitted rays are intercepted. + +The whole apparatus is suspended from a long cable, formed of two +conducting wires, which winds around a windlass with metallic +journals which are electrically insulated. These journals communicate, +through the intermedium of two friction springs, with the conductors +on the one hand and, on the other, with the poles of an automatic and +portable battery. + +[Illustration: THE TROUVE ERYGMASCOPE.] + +This permits of lowering and raising the apparatus at will, without +derangement, and without its being necessary to interrupt the light +and the observation.--_Revue Industrielle._ + + * * * * * + + + + +A NEW ELECTRIC BALLISTIC TARGET. + + +The electrical target usually employed in determining velocities of +projectiles consists of a wooden frame on which is strung a copper +wire so as to make a continuous circuit arranged in parallel vertical +lines about one inch or one and one half inches apart. + +It frequently happens that a projectile will pass through this target +without breaking the circuit, either by squeezing between the wires or +because, when last repaired, the target was short-circuited unnoticed, +so that the cutting of the wires did not break the circuit. The repair +of this target takes considerable time. + + _______________________________________________________ + | { + | +-------------__ --------------__---------------- } + | | _ // \\ // \\ } { + | | |_| || C_{0} || A || || || A { } + | | P \\ // \\ // } { + | +------------- --------------- ---------------- } + | F { + |_______________________________________________________} + + Plan. + P C + =|= _________ + |===| ========= A A + ========| | S |========\_______/================= + |spring | | | + | | | | | + |S_ | __| |__ __| + ||| | | + ___________|||______________| |_____________________ + | + | Section. + H / + \+/ + | + | + | + | + | + | + _____+_____ + | | + | W | + | | + |___________| + + +Besides these objections to this target, another and more serious one +is the irregularity in the manner of breaking the circuit. It has been +proved that times required for a flat headed and an ogival headed +projectile to rupture the current are very different. + +To remedy these defects a new and very ingenious target has been +devised and used with great success at the United States Military +Academy at West Point. The top of the target is a wooden strip, F, on +the upper side of which are screwed strips of copper, A A, about 1/2 +in. wide, and 1/8 in. thick. The connection between two adjoining +strips is made by a copper cartridge, C, which is dropped in a hole in +the frame bored to receive it. This cartridge is the one used in the +Springfield rifle. Inside the cartridge is a spiral spring, S, which, +acting on the bottom of the hole and the head of the cartridge, tends +to make the latter spring up, and so break the circuit. + +To the hook, H, which is attached to the cartridge, is suspended, by +means of a string, the lead weight, W, thus drawing down the cartridge +and making the circuit between A and A'. All the weights being +suspended the current comes in through the post, P, passes along the +copper strips and out of the corresponding post on the other end. + +On firing the projectile cuts a string, and the spring at once causes +the cartridge to spring up, thus breaking the circuit. + +It is not possible for the projectile to squeeze between the strings +and not break the current, for in so doing the cartridge is tipped +slightly, which is sufficient, as it breaks the current on one side. + +This target is used in connection with the Boulenge chronograph. Two +targets are established at a known distance apart, say 50 ft., and the +time required for the projectile to pass over this distance is +determined by finding the difference in the time of cutting of the two +targets, by finding the difference in the time of falling of the two +rods, caused by the demagnetization of two electromagnets in the same +circuit with the targets. + +By means of a disjunctor both rods are dropped at the same time, the +shorter one releasing a knife blade which makes a cut on the longer +one. Now both rods are hung from the magnets again and the gun is +fired. + +The projectile passes through the first target, breaks the circuit, +demagnetizes the magnet of the longer rod, and it begins to fall. On +passing through the second target, the projectile causes the shorter +rod to fall. This releases the knife blade, and a second cut is made. +The time corresponding to the distance between these cuts is the time +the longer rod was falling before the second rod began to fall or the +time between the cutting of the two targets by the projectile. + +The distance between the cuts is measured, and the time corresponding +to it can easily be found. Then the velocity of the projectile is +equal to 50/t. + +To repair this target, strings are prepared in advance of suitable +length and looped at both ends, so that by placing the hook of the +cartridge in one loop and that of the weight in the other the repair +is quickly made. + +This target has been used on the West Point proving ground to +determine velocities over distances of 100 ft. interval to distances +of only 9 ft. interval, and has given most satisfactory results. + + * * * * * + +[Continued from SUPPLEMENT, No. 786, page 12566.] + + + + +THE OUTLOOK FOR APPLIED ENTOMOLOGY. + +[Footnote: Address of Dr. C.V. Riley at the annual meeting of the +Association of Economic Entomologists, Champaign, Ills., November 11 +to 14, 1890.] + +LEGISLATION. + + +The amount of legislation in different countries that has of late +years been deemed necessary or sufficiently important, in view of +injurious insects, is a striking evidence of the increased attention +paid to applied entomology; and while modern legislation of this kind +has been, on the whole, far more intelligent than similar efforts in +years gone by, many of the laws passed have nevertheless been unwise, +futile, and impracticable, and even unnecessarily oppressive to other +interests. The chief danger here is the intervention of politics or +political methods. Expert counsel should guide our legislators and the +steps taken should be thorough in order to be effective. We have had +of late years in Germany very good evidence of the excellent results +flowing from thorough methods, and the recent legislation in +Massachusetts against the gypsy moth (_Ocneria dispar_), which at one +time threatened to become farcical, has, fortunately, proved more than +usually successful; the commission appointed to deal with the subject +having worked with energy and followed competent advice. + + +PUBLICATION. + +On the question of publication of the results of our labors it is +perhaps premature to dwell at length. Each of the experiment stations +is publishing its own bulletins and reports quite independently of the +others, but after a uniform plan recommended by the association with +which we meet here; and with but one exception that has come to my +notice, another important recommendation of the same association--that +these publications shall be void of all personal matter--has been kept +in mind. The National Bureau of Experiment Stations at Washington is +doing what it can with the means at command to further the general +work by issuing the Experiment Station Record, devoted chiefly to +digests of the State station bulletins. There is a serious question in +my mind as to the utility of State digests by the national department +of results already published extensively by the different States and +distributed under government frank to all similar institutions and to +whomsoever is interested enough to ask for them. + +Such digests may or may not be intelligently made, and, even under the +most favorable circumstances, will hardly serve any other purpose than +helping to the reference to the original articles, and this could +undoubtedly be done more satisfactorily to the stations and to the +people at large by general and classified indices to all the State +documents, made as full as possible and issued at stated intervals. +Only a small proportion of the bulletins have been so far noticed by +digest in this record, with no particular rule, so far as I can see, +in the selection. In point of fact, those will be most apt to be +noticed whose authors can find time to themselves send or make for the +purpose their own abstracts. This is, perhaps, inevitable under +present arrangements. Complete and satisfactory digests of all, if +intelligent and critical, imply a far greater force than is at present +at Prof. Atwater's command. + +Under these circumstances, it would seem wiser to devote all the +energies of the bureau to digests of the similar literature of other +countries, which would be of immense advantage to our people and to +the different station workers. Judging from the recommendations and +resolutions of the general association, this is the view very +generally held, but except in chemistry and special industries like +that of beet sugar, very little of that kind of work has yet been +attempted. + +What is true of the station publications in general is equally true of +special publications. As entomologist of the department, I have been +urged to bring together, at stated intervals, digests of the +entomological publications of the different stations. Such digests to +be of any value, however, should also be critical, and it were a +thankless task for any one to be critic or censor even of that which +needs correction or criticism. Moreover, to do this work intelligently +would require increase of the divisional force, which at present is +more advantageously employed, for, as already intimated, I should have +great doubts of the utility of these digests. + +I believe, however, that the division should strive for such increase +of means as would justify the periodic publication, either +independently or as a part of the department record, of general and +classified indices to the entomological matter of the station +bulletins, and should work more and more toward giving results from +other parts of the world. This could, perhaps, best be done by titles +of subject and of author so spaced and printed on stout paper that +they could be cut and used in the ordinary card catalogue. The +recipient could cut and systematically place the titles as fast as +received. + +As to the character of the matter of the entomological bulletins, it +will inevitably be influenced by the needs and demands of the people +of the respective States, and while originality should be kept in +mind, there must needs be in the earlier years of the work much +restatement of what is already well known. That some results have been +published of work which reflects no particular credit upon our calling +is a mere incident of the new positions created. Yet we may expect +marked improvement from year to year in this direction, and without +being invidious, I would cite those of Prof. Gillette's on his +spraying experiments and on the plum curculio and plum gouger, as +models of what such bulletins should be. + +Although the resolution offered at our last meeting by Prof. Cook, to +the effect that purely descriptive matter should be excluded from the +station bulletins, met with no favor, but was laid on the table, by +the general association, I am in full sympathy with this position and +am strongly of the opinion that in the ordinary bulletins such purely +technical and descriptive matter should be reduced to the necessary +minimum consistent with clearness of statement and accuracy, and that +if it is desired, on the part of the station entomologists, to issue +technical and descriptive papers, a separate series of bulletins were +better instituted for this class of matter. + +Finally, for results which it is desired to promptly get before the +people, the agricultural press is at our disposal, and so far as the +entomological work of the department of agriculture is concerned, the +periodical bulletin, _Insect Life_, was established for this purpose. +Its columns are open to all station workers, and I would here appeal +to the members of the association to help make it, as far as possible, +national, by sending brief notes and digests of their work as it +progresses. Hitherto we have been unable to make as much effort in +this direction as we desired, but in future it is our hope to make the +bulletin, as far as possible, a national medium through which the +results of work done in all parts of the country may quickly be put on +record and distributed, not only to all parts of our own country, but +to all parts of the world. + +The rapid growth and development of the national department and the +multiplication of its divisions have necessitated special modes of +publication and rendered the annual report almost an anachronism so +far as it pretends to be what it at one time was--a pretty complete +report of the scientific and other work of the department. The +attempts which I have made through the proper authorities to get +Congress to order more pretentious monographic works in quarto volume +similar to those issued by other departments of the government have +not met with encouragement, and in this direction many of the stations +will, let us hope, be able to do better. + + +CO-OPERATION. + +Every other subject that might be considered on this occasion must be +subordinate to the one great question of co-operation. With the large +increase of actual workers in our favorite field, distributed all over +the country, the necessity for some co-operation and co-ordination +must be apparent to every one. Just how this should be brought about +or in what direction we may work toward it, will be for this +association in its deliberations to decide. Nor will I venture to +anticipate the deliberations and conclusions of the special committee +appointed to take the matter into consideration, beyond the statement +that there are many directions in which we can adopt plans for mutual +benefit. Take, for instance, the introduction and dissemination of +parasites. How much greater will be the chance of success in any +particular case if we have all the different station entomologists +interested in some specific plan to be carried out in co-operation +with the national department, which ought to have better facilities of +introducing specimens to foreign countries or to different sections of +our own country than any of the State stations. + +Let us suppose that the fruit growers of one section of the country, +comprising several States in area, need the benefit in their warfare +against any particularly injurious insect of such natural enemy or +enemies as are known to help the fruit growers of some other section. +There will certainly be much greater chances of success in the +carrying out of any scheme of introduction if all the workers in the +one section may be called upon through some central or national body +to help in the introduction and disposition of the desired material +into the other section. Or, take the case of the boll worm +investigation already alluded to. The chances of success would be much +greater if the entomologists in all the States interested were to give +some attention to such lepidopterous larvæ as are found to be affected +with contagious diseases and to follow out some specific plan of +cultivating and transmitting them to the party or parties with whom +the actual trials are intrusted. The argument applies with still +greater force to any international efforts. I need hardly multiply +instances. There is, it is true, nothing to prevent any individual +station entomologist from requesting co-operation of the other +stations, nor is there anything to prevent the national department +from doing likewise; but in all organization results are more apt to +flow from the power to direct rather than from mere liberty to request +or to plead. The station entomologist may be engrossed in some line of +research which he deems of more importance to the people of his State, +and may resent being called upon to divert his energies; and with no +central or national power to decide upon plans of co-operation for the +common weal, we are left to voluntary methods, mutually devised, and +it is here that this association can, it seems to me, most fully +justify its organization. And this brings me to the question of + + +THE DEPARTMENT AND THE STATIONS. + +Immediately connected with the question of co-operation is the +relation of the National Department of Agriculture and the State +experiment stations. The relation, instead of being vital and +authoritative, is, in reality, a subordinate one. Many persons +interested in the advancement of agriculture foresaw the advantage of +having experiment stations attached to the State agricultural colleges +founded under the Morrill act of 1862; but I think that in the minds +of most persons the establishment of these stations implied some such +connection with the national department as that outlined in an address +on Agricultural Advancement in the United States, which I had the +honor to deliver in 1879 before the National Agricultural Congress, at +Rochester, and in which the following language was used: + + "In the light of the past history of the German experimental + stations and their work, or of that in our own State of + Connecticut, the expediency of purchasing an experimental farm of + large dimensions in the vicinity of Washington is very + questionable. There can be no doubt, however, of the value of a + good experimental station there that shall have its branches in + every State of the Union. The results to flow from such stations + will not depend upon the number of acres at command, and it will + be far wiser and more economical for the commissioner to make each + agricultural college that accepted the government endowment + auxiliary to the national bureau, so that the experimental farm + that is now, or should be, connected with each of these + institutions might be at its service and under the general + management of the superintendent of the main station. There is + reason to believe that the directors of these colleges would + cheerfully have them constituted as experimental stations under + the direction of the department, and thus help to make it really + national--the head of a vast system that should ramify through all + parts of the land.... + + "With the different State agricultural colleges, and the State + agricultural societies, or boards, we have every advantage for + building up a national bureau of agriculture worthy of the country + and its vast productive interests, and on a thoroughly economical + basis, such as that of Prussia, for instance." + +In short, the view in mind was something in the nature of that which +has since been adopted by our neighbors of the North, where there is a +central or national station or farm at Ottawa and sub-stations or +branch farms at Nappan, Nova Scotia, Brandon, Manitoba, Indian Head, +N.W.T., and Agassiz, British Columbia, all under the able direction of +Mr. William Saunders, one of our esteemed fellow workers. It was my +privilege to be a good deal with Mr. Saunders when he was in Europe +studying the experience of other countries in this matter, and the +policy finally adopted in Canada as a result of his labors is an +eminently wise one, preventing some of the difficulties and dangers +which beset our plan, whether as between State and nation or college +and station. + +Under the present laws and with the vast influence which the +Association of Agricultural Colleges and Experiment Stations will +wield, both in Congress and in the different States, there is great +danger of transposition, in this agricultural body politic, of those +parts which in the animal body are denominated head and tail, and the +old saw to the effect that "the dog wags the tail because the tail +cannot wag the dog," will find another application. So far as the law +goes, the national department, which should hold a truly national +position toward State agricultural institutions depending on federal +support, can do little except by suggestion, whether in the line of +directing plans or in any way co-ordinating or controlling the work of +the different stations throughout the country. The men who influenced +and shaped the legislation which resulted in the Hatch bill were +careful that the department's function should be to indicate, not to +dictate; to advise and assist, not to govern or regulate. We have, +therefore, to depend on such relationships and such plans of +co-operation as will appear advantageous to all concerned, and these +can best be brought about through such associations as are now in +convention here. + +Without such plans there is great danger of such waste of energy and +means and duplication of results as will bring the work into popular +disfavor and invite disintegration, for already there is a growing +feeling that agricultural experiment is and will be subordinated to +the ordinary college work in the disposition of the federal +appropriations. + +What is true of the national department as a whole in its connection +with the State stations is true in a greater or less degree of the +different divisions of the department in connection with the different +specialists of the stations. With the multiplicity of workers in any +given direction in the different States, the necessity for national +work lessens. A favorite scheme of mine in the past, for instance (and +one I am glad to say fully indorsed by Prof. Willits), was to endeavor +to have a permanent agent located in every section of the country that +was sufficiently distinctive in its agricultural resources and +climate, or, as a yet further elaboration of the same plan, one in +each of the more important agricultural States. The necessity for such +State agents has been lessened, if not obviated, by the Hatch bill, +and the subsequent modifications looking to permanent appropriations +to the State stations or colleges, which give no central power at +Washington. The question then arises, What function shall the national +department perform? Its influence and field for usefulness have been +lessened rather than augmented in the lines of actual investigation in +very many directions. Many a State is already far better equipped both +as to valuable surrounding land, laboratory and library facilities, +more liberal salaries, and greater freedom from red tape, +administrative routine, and restrictions as to expenditures, than we +are at Washington; and, except as a directing agent and a useful +servant, I cannot see where the future growth of the department's +influence is to be outside of those federal functions which are +executive. Just what that directing influence is to be is the question +of the hour, not only in the broader but in the special sense. The +same question, in a narrower sense, had arisen in the case of the few +States which employed State entomologists. In the event, for instance, +of an outbreak of some injurious insect, or in the event of any +particular economic entomological question within the limits of the +State having such an officer, the United States entomologist would +naturally feel that any effort on his part would be unnecessary, or +might even be looked upon as an interference. He would feel that there +was always danger of mere duplication of observation or experiment, +except where appealed to for aid or co-operation. This is, perhaps, +true only of insects which are local or sectional, and is rather a +narrow view of the matter, but it is one brought home from experience, +and is certainly to be considered in our future plans. The favor with +which the museum work of the national division was viewed by you at +the meeting last November and the amount of material sent on for +determination would indicate that the building up of a grand national +reference collection will be most useful to the station workers. But +to do this satisfactorily we need your co-operation, and I appeal to +all entomologists to aid in this effort by sending duplicates of their +types to Washington, and thus more fully insuring against ultimate +loss thereof. + + +STATUS OF OUR SOCIETY. + +This train of thought brings up the question of the status of our +society with the station entomologists as represented by the committee +of the general association. Those of us who had desired a national +association for the various purposes for which such associations are +formed, felt, I believe, if I may speak for them, that the creation of +the different experimental stations rendered such an organization +feasible. Your organization at Toronto and the constitution adopted +and amended at the meeting at Washington all indicate that the chief +object was the advancement of our chosen work and that the strength of +the association would come from the experiment station entomologists. +There was then no other organization of the kind, nor any intimation +that such a one would be founded. Some of us therefore were surprised +to learn from the circular sent out by Prof. Forbes, its chairman, +that the committee appointed by the association of agricultural +colleges and experiment stations, and through which we had hoped to +communicate and co-operate with that association, was not in the +proper sense a committee, but a section which has prepared (and in +fact was required by the executive committee and the rules of the +superior body to prepare) a programme of papers and discussions for +the meeting to be held at the same time and place with our own. I +cannot but feel that this is in some respects a misfortune, and it +will devolve upon you to decide upon several questions of importance +that will materially affect our future existence. That there is not +room for two national organizations having the same objects in view +and meeting at the same time and place goes, I think, without saying; +and if the committee of the general association is to be anything more +than a committee in the proper sense of the word, or if it is to +assume with or without formal constitution the functions of our own +association, then our own must necessarily be crippled, and to do any +good at all must meet at a different time and a different place. A +committee or section, or whatever it may be called, of the general +association with which we meet, would preclude active membership of +any but those who come within the constitution of that body. Our +Canadian friends and many others who have identified themselves with +applied entomology, and do not belong to any of our State or +government institutions, would be debarred from active representation, +however liberal the association may have been in inviting such to +participate, without power to vote in its deliberations. Our own +association has, or should have, no such limitations. Some of us who +are entitled to membership in both bodies may feel indifferent as to +the course finally decided upon, and that it will not make any +difference whether we have an outside and independent organization, as +that of the association of official chemists, or whether we do, as did +the botanists and horticulturists, waive independence in favor of more +direct connection with the general association, provided there is some +way whereby the committees of the general association are given +sufficient latitude and time to properly present their papers and +deliberate; but there are others who feel more sensitive as to their +action and are more immediately influenced by the feelings of the main +body. I hope that whatever action be taken at this meeting, the +general good and the promotion of economic entomology will be kept in +mind and that no sectional or personal feeling will be allowed to +influence our deliberations. + + +SUGGESTION AND COMMENT. + +You will, I know, pardon me if, before concluding these remarks, I +venture to make a few comments which, though not altogether agreeable, +are made in all sincerity and in the hope of doing good. The question +as to how far purely technical and especially descriptive and +monographic work should be done by the different stations or by the +national department is one which I have already alluded to and upon +which we shall probably hold differing opinions, and which will be +settled according to the views of the authorities at the different +stations. Individually, I have ever felt that one ostensibly engaged +in applied entomology and paid by the State or national government to +the end that he may benefit the agricultural community can be true to +his trust only by largely overcoming the pleasure of entomological +work having no practical bearing. I would, therefore, draw the line at +descriptive work except where it is incidental to the economic work +and for the purpose of giving accuracy to the popular and economic +statements. This would make our work essentially biological, for all +biologic investigation would be justified, not only because the life +habits of any insect, once ascertained, throw light on those of +species which are closely related to it, but because we can never know +when a species at present harmless may subsequently prove harmful, and +have to be classed among the species injurious to agriculture. + +On the question of credit to their original sources of results already +on record, it is hardly necessary for me to advise, because good sense +and the consensus of opinion will in the end justify or condemn a +writer according as he prove just and conscientious in this regard. + +There is one principle that should guide every careful writer, viz., +that in any publications whatever, where facts or opinions are put +forth, it should always be made clear as to which are based upon the +author's personal experience and which are compiled or stated upon the +authority of others. We should have no patience with a very common +tendency to set forth facts, even those relating to the most common +and best known species, without the indications to which I have +referred. The tendency belittles our calling and is generally +misleading and confusing, especially for bibliographic work, and +cannot be too strongly deprecated. + +On this point there will hardly be any difference of opinion, but I +will allude to another question of credit upon which there prevails a +good deal of loose opinion and custom. It is the habit of using +illustrations of other authors without any indication of their +original source. + +This is an equally vicious custom and one to be condemned, though I +know that some have fallen into the habit, without appreciation of its +evil effect. It is, in my judgment, almost as blameworthy as to use +the language or the facts of another without citing the authority. + +Every member of this association who has due appreciation of the time +and labor and special knowledge required to produce a good and true +illustration of the transformations and chief characteristics of an +insect will appreciate this criticism. However pardonable in fugitive +newspaper articles in respect of cuts which, from repeated use, have +become common or which have no individuality, the habit inevitably +gives a certain spurious character to more serious and official +publications, for assumption of originality, whether intended or not, +goes with uncredited matter whether of text or figure. Nor is mere +acknowledgment of loan or purchase to the publisher, institution or +individual who may own the block or stone what I refer to. But that +acknowledgment to the author of the figure or the work in which it +first appears which is part of conscientious writing, and often a +valuable index as to the reliability of the figure. + +It were supererogation to point out to a body of this kind the value +of the most careful and thorough work in connection with life +histories and habits, often involving as it does much microscopic +study of structure. The officers of our institutions who control the +funds, and more or less fully our conduct, are apt to be somewhat +impatient and inappreciative of the time given to anatomic work, and +where it is given for the purpose of describing species and of +synopsizing or monographing higher groups, without reference to +agriculture, I am firmly of the belief that it diverts one from +economic work, but where pursued for a definite economic purpose it +cannot be too careful or too thorough and I know of no instances +better calculated to appeal to and modify the views of those inclined +to belittle such structural study than Phylloxera and Icerya. On the +careful comparison of the European and American specimens of +_Phylloxera vastatrix_, involving the most minute structures and +details, depended originally those important economic questions which +have resulted in legislation by many different nations and the +regeneration of the affected vineyards of Europe, of our own Pacific +coast, and of other parts of the world by the use of American +resistant stocks. In the case of _Icerya purchasi_ the possibilities +of success in checking it by its natural enemies hung at one time upon +a question of specific difference between it and the _Icerya sacchari_ +of Signoret--a question of minute structure which the descriptions +left unsettled and which could only be settled by the most careful +structural study and the comparison of the types, involving a trip to +Europe. + + +CONCLUSION. + +I have thus touched, gentlemen, upon a few of the many subjects that +crowd upon the mind for consideration on an occasion like this--a few +gleanings from a field which is passing rich in promise and +possibility. It is a field that some of us have cultivated for many +years and yet have only scratched the surface, and if I have ventured +to suggest or admonish, it is with the feeling that my own labors in +this field are ere long about to end and that I may not have another +occasion. + +At no time in the history of the world has there, I trow, been +gathered together such a body of devoted and capable workers in +applied entomology. It marks an era in our calling and, looking back +at the progress of the past fifteen years, we may well ponder the +possibilities of the next fifteen. They will be fruitful of grand +results in proportion as we persistently and combinedly pursue the yet +unsolved problems and are not tempted to the immediate presentation of +separate facts, which are so innumerable and so easily observed that +their very wealth becomes an element of weakness. Epoch-making +discoveries result only from this power of following up unswervingly +any given problem, or any fixed ideal. The kerosene emulsion, the +Cyclone nozzle, the history of _Phylloxera vastatrix_, of _Phorodon +humuli_, of _Vedalia cardinalis_, are illustrations in point, and +while we may not expect frequent results as striking or of as wide +application as these, there is no end of important problems yet to be +solved and from the solution of which we may look for similar +beneficial results. Applied entomology is often considered a sordid +pursuit, but it only becomes so when the object is sordid. When +pursued with unselfish enthusiasm born of the love of investigation +and the delight in benefiting our fellow men, it is inspiring, and +there are few pursuits more deservedly so, considering the vast losses +to our farmers from insect injury and the pressing need that the +distressed husbandman has for every aid that can be given him. Our +work is elevating in its sympathies for the struggles and suffering of +others. Our standard should be high--the pursuit of knowledge for the +advancement of agriculture. No official entomologist should lower it +by sordid aims. + +During the recent political campaign the farmer must have been sorely +puzzled to know whether his interests needed protection or not. On the +abstract question of tariff protection to his products we, as +entomologists, may no more agree than do the politicians or than does +the farmer himself. But ours is a case of protection from injurious +insects, and upon that there can nowhere be division of opinion. It is +our duty to see that he gets it with as little tax for the means as +possible. + + * * * * * + + + + +POTASH SALTS. + +[Footnote: By John B. Smith, entomologist. Potash as an insecticide is +not entirely new, but has never been brought out with the prominence I +think it deserves.--_N.J. Ag. Col. Exp. St., Bulletin 75._] + + +My attention was attracted to potash salts as an insecticide, by the +casual remark of an intelligent farmer, that washing his young pear +trees with a muriate of potash solution cleared them of scales. The +value of this substance for insecticide purposes, should its powers be +sufficient, struck me at once, and I began investigation. It was +unluckily too late in the season for field experiments of the nature +desired; but it is the uniform testimony of farmers who have used +either the muriate or the kainit in the cornfields, that they have +there no trouble with grubs or cut worms. Mr. E.B. Voorhees, the +senior chemist of the station, assures me that on his father's farm +the fields were badly infested, and replanting cornhills killed by +grubs or wire worms was a recognized part of the programme. Since +using the potash salts, however, they have had absolutely no trouble, +and even their previously worst-infested fields show no further trace +of injury. The same testimony comes from others, and I feel safe in +recommending these salts, preferably kainit, to those who are troubled +with cut worms or wire worms in corn. + + +EXPERIMENTS. + +A lot of wire worms (_Iulus_ sp.) brought in from potato hills were +put into a tin can with about three inches of soil and some potato +cuttings, and the soil was thoroughly moistened with kainit, one ounce +to one pint of water. Next morning all the specimens were dead. A +check lot in another can, moistened with water only, were healthy and +lived for some days afterward. + +A number of cabbage maggots placed on the soil impregnated with the +solution died within twelve hours. + +To test its actual killing power, used the solution, one ounce kainit +to one pint water, to spray a rose bush badly infested with plant +lice. Effect, all the lice dead ten hours later; the younger forms +were dropping within an hour. + +Sprayed several heads of wheat with the solution, and within three +hours all the aphides infesting them were dead. + +Some experiments on hairy caterpillars resulted unsatisfactorily, the +hair serving as a perfect protection against the spray, even from the +atomizer. + +To test its effect on the foliage, sprayed some tender shoots of rose +and grape leaves, blossoms, and clusters of young fruit. No bad effect +observable 24 hours later. There was on some of the leaves a fine +glaze of salt crystals, and a decided salt taste was manifest on all. + +Muriate of potash of the same strength was tested as follows: Sprayed +on some greenhouse camellias badly infested by mealy bugs, it killed +nearly all within three hours, and six hours later not a living insect +was found. The plants were entirely uninjured by the application. + +Thoroughly sprayed some rose bushes badly infested with aphides, and +carried off some of the worst branches. On these the lice were dead +next morning; but on the bushes the effect was not so satisfactory, +most of the winged forms and many mature wingless specimens were +unaffected, while the terminal shoots and very young leaves were +drooping as though frosted. All, however, recovered later. + +The same experiment repeated on other, hardier roses, resulted +similarly so far as the effect on the aphides was concerned, but there +was no injury to the plant. + +Used this same mixture on the caterpillars of _Orgyia leucostigma_ +with unsatisfactory effect, and with the same results used it on a +number of other larvæ. Used on the rose leaf roller, _Cacæcia +rosaceana_, it was promptly effective. + +Tested for injury to plants, it injured the foliage and flowers of +wisteria, the younger leaves of maple and grape, and the finer kinds +of roses. + +From these few experiments kainit seems preferable to the muriate, as +acting more effectively on insects and not injuriously on plants. For +general use on plants it is not to be recommended. It is otherwise on +underground species, where the soil will be penetrated by the salts +and where the moisture evaporates but slowly, and the salt has a +longer and better chance to act. The best method of application would +be a broadcasting in fertilizing quantity before or during a rain, so +as to carry the material into the soil at once. In cornfields infested +with grubs or wire worms, the application should be made before +planting. Where it is to be used to reach root lice, it should be used +when the injury is beginning. When strawberry beds are infested by the +white grub, the application should be made when cultivating or before +setting out. + +The potash salts have a high value as fertilizers, and any application +made will act as a stimulant as well as insecticide, thus enabling the +plants to overcome the insect injury as well as destroying the insect. + +In speaking on this subject in Salem county, I learned from farmers +present that those using potash were not troubled with the corn root +louse to any extent, and also that young peach trees have been +successfully grown in old lice-infested orchards, where previously all +died, by first treating the soil with kainit of potash. + + * * * * * + + +A meteorological station has been built on Mont Blanc, at an elevation +of 13,300 feet, under the direction of M. Vallot. It required six +weeks to deliver the materials. The instruments are self-registering +and are to be visited in summer every fifteen days if possible, the +instruments being left to register between the visits. In the winter +the observatory will be entirely inaccessible. This is the highest +scientific station in Europe, but is 847 feet lower than the Pike's +Peak station in Colorado. + + * * * * * + + + + +THE EXPENSE MARGIN IN LIFE INSURANCE. + + +The principle of mutuality requires that the burden of expense in life +insurance should be borne by all the members equally; but, even with +the most careful adjustment, the allowance usually made is +considerably in excess of what is needed in the regular companies +doing business on the "level premium" plan. + +It is customary in these companies to add to the net premium a +percentage thereof to cover the expense account. This practice, though +in harmony with the "commission system," is so clearly defective and +so far removed from the spirit of life insurance mathematics, that it +scarcely deserves even this passing notice. + +It is generally understood that these corporations combine the +functions of the savings bank and life insurance company, and it is +only by separating the two in our minds as far as possible that we can +obtain a clear conception of the laws that should govern the +apportionment of the expenses among the great variety of policies. + +While it is a comparatively simple matter to state the amount of +either the insurance or savings bank element in a single policy, it is +by no means easy, as things go, to classify the company's actual +expenses on this basis. + +Fortunately, we can pretty accurately determine what these amounts +should be in any particular case. + +In the first place, there are institutions in our midst devoted solely +to receiving and conserving small sums of money; doing, in fact, +exactly what our insurance companies are undertaking to do with the +reserve and contributions thereto. These savings banks are required by +law to make returns to the State commissioner, from whose official +report we can get a very good idea of the expense attendant on doing +this business. + +Confining ourselves to the city banks, where the conditions more +nearly resemble those of the insurance companies, we find in +thirty-eight combined institutions for saving in the State of +Massachusetts a deposit in 1888 of $192,174,566, taken care of at an +aggregate cost of $455,387, or about 24-100 of one per cent. + +The same ratio carried out for all the savings banks in Massachusetts +gives a trifle over 25-100 of one per cent.; we may, therefore, +consider ¼ of one per cent. as expressing pretty nearly the cost of +receiving, paying out, and investing the savings of the people. + +We must remember in this connection that in the popular estimation, +the savings bank is an important factor in the public welfare, and in +the towns and smaller cities there are often found public spirited men +willing to give their services to encourage this mode of saving; but +public sentiment has not yet given to life insurance the place which +it is destined, sooner or later, to occupy by the side of the savings +bank. Hence the services of able managers can only be obtained by a +liberal outlay of the corporate funds. A satisfactory adjustment of +the matter of expenses will, perhaps, do more than anything else to +bring about this recognition on the part of the public. + +In the case of the savings bank it is safe to say that for double the +present outlay a liberal salary could be paid to all the officers. +Following the analogy, we are led to infer that if this be the case in +savings banks, then ½ of one per cent. of the reserve should be an +ample allowance for the special labor required in the purely banking +portion of the business. + +In this we have the concurrence of the late Elizur Wright. In an essay +on this subject he says: + + "The expenses of the five largest savings banks in Boston, in + 1869, did not exceed 4-10 of one per cent. on $28,000,000 + deposited in them. They certainly had twice as many transactions, + in proportion to the deposits, as any life insurance company could + have with the same amount of reserve, so that ½ of one per cent. + on the reserve seems to be ample for all working expenses save + those of maintaining the agencies and collecting the premiums." + +This need hardly be looked upon as an admission that it costs twice as +much to care for the funds of a life insurance company as for those of +a savings bank. A liberal expense allowance must be made at the +outset, seeing that an error in this particular cannot easily be +rectified after the policy is issued. The dividend, or, to speak more +correctly, the annual return of surplus, will correct any overpayment +on this account. + +There is another expense which seems inevitable. This is the +government tax on insurance companies, amounting in the aggregate to +nearly 1/3 of one per cent. on the reserve. + +When we consider that these institutions are intended to encourage +thrift and to relieve the community from the care of numberless widows +and orphans, it seems a clear violation of the principles of political +economy to levy a tax on this business; still, whatever our opinion +may be as to the justice or injustice of the imposition, the tax is +maintained and must be provided for. Consequently a further allowance +of ½ of one per cent. must be added to the net premium to cover the +same, making a total of 1 per cent. of the reserve for banking +expenses and taxes. Considering this point as settled for the time +being, let us proceed to investigate the insurance expenses. + +Here, again, we are fortunate in being able to refer to the official +reports of a class of corporations doing nearly, if not quite pure +insurance. + +The assessment societies, outside of the fraternal and benevolent, +reporting in 1889 to the insurance commissioner of Massachusetts, show +outstanding risks amounting to $733,515,366. Losses to the amount of +$7,270,238 were paid during the year at a cost for transacting the +business of $2,403,053, which includes among other items "agency +expenses and commissions," which amount to about $1,203,000, or 17 per +cent. of the cost value of the insurance actually done. It would seem +as if an allowance of 20 per cent. would be a liberal one in the case +of the regular companies, which surely have as good facilities for +doing business as the assessment societies. + +As far as insurance is concerned, there is less difference between +regular and co-operative companies than is generally supposed. Regular +companies assess each policy in advance for a year's insurance at a +time, while co-operative societies furnish insurance only from one +assessment to another. The difficulty in the way of collecting the +assessment in the latter case would seem to be greater than in the +former, owing to the more permanent nature of the regular insurance +contract. + +In compensating agents the assessment companies naturally pay in +proportion to the insurance obtained, inasmuch as there is no other +basis to go upon, but regular companies usually pay the agent a +percentage of the premium _which includes a considerable trust fund_ +over and above the assessment for actual insurance. It is easily seen +that by the last method the agent's compensation increases in +proportion to the amount of savings bank business forced upon the +company. + +To realize how far we are from anything like a scientific, not to say +common sense basis for insurance expenses, we have but to examine the +following list, which gives the ratios between the expenditures for +general expenses in 1889, and those for the extension of the business. +For every $100 used in a general way, the different companies spend +for commissions and agency expenses: $37, $66, $67, $78, $91, $106, +$110, $113, $120, $140, $157, $161, $173, $175, $186, $189, $200, +$202, $222, $264, $311, $346. + +It will doubtless be said that I am taking a very advanced position +when I say that in the ideal life insurance scheme there is no place +for the commission system. Solicitors will be a necessity only so long +as they are in the field, but fifty years of life insurance has taught +our community its true value and, thanks to the modern press, the +institution it is no more likely to fall into desuetude than is +Christianity or the moral law. + +For the convenience of bringing the company to the individual, the +latter should be willing to pay a fee. The man who renders another a +service or puts his superior knowledge at another's disposal should +look to the party benefited for his remuneration. Any compensation +given for such service to a go-between by a mutual company is paid by +all, and the question arises, Is the advantage to the company of +sufficient importance to warrant the imposition of this tax upon all +its members promiscuously? The following, from the Massachusetts +Insurance Commissioner's Report for 1885, leaves no doubt as to the +convictions of the writer on this important matter: + + "The expensiveness of the life insurance policy is not because the + level net premium is too high, for the premium is absolutely just, + and the policy holder gets full value; but the complaint justly + applies to the excessive expense charge. A person who wants + insurance, life or fire or other, should be able to buy it at + first cost without paying tribute of profits to middlemen. To that + complexion the matter will finally be brought by the force of + intelligent opinion, whatever resistance may be opposed by persons + whose thrift lies in the perpetuation of the expensive system now + in fashion." + +It requires but a slight degree of prophetic vision to predict that in +a very few years the companies in self defense will be obliged to +change their method of compensating agents. + +Several companies have already begun the reform by grading +commissions; granting a percentage proportional to the amount of +insurance likely to be done on the policy. Other companies have simply +reduced the amount of the commission rate, thus virtually withdrawing +from active competition. + +This will, in a certain degree, explain the wide variation in the +figures given above, where it is noticed that, in five companies out +of twenty-two, the total agency expenditures amount to less than the +general expenses, while in six cases the companies spend more than +double as much on the former as on the latter. In either class we find +representatives of the five largest companies in the country. + +On applying the foregoing ratios to the business of the existing +companies we find that, calling the theoretical expenses $100, the +actual expenditures for 1889 were as follows: $112.67, $118.34, +$150.40, $194.48, $208.16, $208.53, $228.66, $235.89, $248.44, +$250.79, $258.33, $258.57, $265.14, $267.19, $267.92, $274.47, +$294.17, $314.96, $335.70, $377.94, $616.70. + +In this discouraging exhibit there is one ray of comfort. The combined +assets of the two companies heading the list amount to over +$100,000,000. There is no question as to their financial standing, and +both show a large increase in membership over the previous year. I may +also say here that it is a difficult matter to get at the actual "cost +of insurance" in the various companies. Many of them, on their own +acknowledgment, do not compute the advance cost of carrying their +"amount at risk," and others, for reasons of their own, do not care to +state the figures. In cases where the correct figures were not +obtainable, I have assumed the cost to have been 1-1/3 per cent. of +the mean amount at risk. + +If we should, in our comparison, omit the actual agency expenses and +commissions, the ratios would stand as follows: + +Where I would allow $100 the companies actually used: $43.17, $55.90, +$65.21, $77.21, $82.39, $88.34, $91.99. $91.98. $92.19, $94.65, +$97.15. $99.55. $99.11. $102.86, $109.35, $125.05, $133.03, $141.92, +$195.90, $207.06, $287.72. + +As might be supposed, the first two ratios are those companies before +alluded to. These companies might have doubled their advertising +account and expended $300,000 between them on agents' salaries, and +still have kept within my allowance. + +Admitting, for the present at least, the reasonableness of the +proposed allowance for the expenses of the banking and insurance +departments of the business, we have before us the problem how to +equitably adjust the burden among the great variety of policies. + +In the first place, _there should be no policy in the company that +does not contribute its proportionate share of the expense allowance +during every year of its life_. I make a special point of this, for at +present the policies which have become paid up, either by the payment +of a single premium at the outset or by the completion of a stipulated +number of payments, contribute practically nothing to the expense +account after the premium payments cease. + +The following plan, I think, complies with all the requirements of the +problem. By the proposed method every policy, at all stages of its +existence, contributes its exact share to the expense fund, whatever +its plan of payment may be. + +Let us, as an illustration, examine the case of a ten year endowment +policy, taken out at age 30, and consider it under three aspects, +first, as paid for in advance by a single payment, second, as paid by +five annual payments, and third, as paid for annually throughout the +term. I have used this short term endowment policy simply for +convenience, the rule applying equally to policies of longer term or +to the ordinary life policy, which is, in fact, an endowment policy +payable at death or age 100.[1] + +[Footnote 1: The expense allowance on a plain life policy for $1,000, +taken at age 33, would be about $5.29; net premium (com. ex. 4 per +cent.), $18.04; total office premium, $23.33; present rate $24.10.] + +Taking the case of the single premium endowment policy for $1,000, we +find that the following sums are required, each year to provide for +the care of the reserve and to pay the government fees (1 per cent. of +reserve): + + 1st year $6.9982 | 6th year $8.4136 + 2d " 7.2560 | 7th " 8.7381 + 3d " 7.5258 | 8th " 9.0781 + 4th " 7.8082 | 9th " 9.4346 + 5th " 8.1039 | 10th " 9.8086 + +The insurance expenses should be covered by the 20 per cent. allowance +given below: + + 1st year $ .4422 | 6th year $ .2566 + 2d " .4100 | 7th " .2076 + 3d " .3762 | 8th " .1556 + 4th " .3402 | 9th " .0988 + 5th " .2996 | 10th " .0344 + +Consequently the total contribution required from this policy each +year is: + + 1st year $7.4404 | 6th year $8.6702 + 2d " 7.6660 | 7th " 8.9457 + 3d " 7.9020 | 8th " 9.2337 + 4th " 8.1484 | 9th " 9.5334 + 5th " 8.4034 | 10th " 9.8430 + +The present value of all these contributions is found to be, at 4 per +cent. interest, $71.6394; in other words, this sum paid at the outset, +provides a fund from which we may deduct the current expenses of each +year in advance, and by accumulating the balance at the assumed rate +of interest from year to year, we shall have enough to pay the +anticipated expenses, leaving nothing over. + +In the above case the sums in hand at the beginning of the year are as +follows: + + 1st year $71.3694 | 6th year $42.6981 + 2d " 66.7669 | 7th " 35.3890 + 3d " 61.4650 | 8th " 27.5009 + 4th " 55.7055 | 9th " 18.9979 + 5th " 49.4594 | 10th " 9.8430 + +We find a somewhat different condition existing during the first years +of a 5-year endowment policy. As there is more insurance and less +banking, the requirements are as follows: + + ------------+----------+-----------+--------+---------+ + | 1 P. Ct. | 20 P. Ct. | | | + | on | on | Total. | Initial | + | Reserve. | Cost. | | Fund. | + ------------+----------+-----------+--------+---------+ + 1st year | $1.5038 | $1.2572 |$2.7610 |$12.9769 | + 2d " | 3.0406 | 1.0216 | 4.0622 | 23.6015 | + 3d " | 4.6503 | .7852 | 5.4355 | 33.2979 | + 4th " | 6.3367 | .5378 | 6.8745 | 41.9538 | + 5th " | 8.1039 | .2996 | 8.4035 | 49.4594 | + 6th " | 8.4136 | .2566 | 8.6702 | 42.6981 | + 7th " | 8.7381 | .2076 | 8.9257 | 35.3890 | + 8th " | 9.0781 | .1556 | 9.2337 | 27.5009 | + 9th " | 9.4346 | .0988 | 9.5334 | 18.9979 | + 10th " | 9.8086 | .0344 | 9.8430 | 9.8430 | + ------------+----------+-----------+--------+---------+ + +As the premium payments extend over only five years, the expense +contributions must all be paid during that time and are most +conveniently made by a uniform addition to the net premium. + +The present value of the amounts in column 3 is $60.0819, and the +equivalent annuity for five years is $12.9769. This amount, received +for five consecutive years, will put the company in funds to pay +current expenses and leave a reserve of $42.6981 at the beginning of +the sixth year, which, as we have seen in the analysis of the +single-premium policy, is the sum required for future expenses on the +paid up basis. + +In like manner we find that the 10-year annuity equivalent to the +present value of the annual contributions in the case of an +annual-payment policy is $5.534, thus: + + ------------+----------+-----------+--------+---------+ + | 1 P. Ct. | 20 P. Ct. | | | + | on | on | Total. | Initial | + | Reserve. | Cost. | | Fund. | + ------------+----------+-----------+--------+---------+ + 1st year | $.8234 | $1.3514 |$2.1748 |$ 5.5340 | + 2d " | 1.6473 | 1.2478 | 2.8951 | 9.0275 | + 3d " | 2.5096 | 1.1388 | 3.6484 | 11.9116 | + 4th " | 3.4124 | 1.0210 | 4.4334 | 14.1277 | + 5th " | 4.3572 | .8916 | 5.2488 | 15.6161 | + 6th " | 5.3479 | .7534 | 6.1013 | 16.3160 | + 7th " | 6.3853 | .5966 | 6.9819 | 16.1572 | + 8th " | 7.4726 | .4270 | 7.8996 | 15.0763 | + 9th " | 8.6127 | .2418 | 8.8545 | 12.9977 | + 10th " | 9.8086 | .0344 | 9.8430 | 9.8430 | + ------------+----------+-----------+--------+---------+ + +The present value of the ten yearly expense items given in the "total" +column above is $46.6812, which is equal to a ten-year annuity of +$5.534. The several premiums stand now as follows: + + ENDOWMENT: $1,000, AGE 30, PAYABLE AT DEATH OR 40 + + Net Prem.[2] Margin. Total. + +At single premium. $687.228 $71.6394 $758.8674 +At five premiums. 150.615 12.9769 163.5939 +At annual premiums. 84.172 5.5340 89.7060 + +[Footnote 2: Thirty American offices. Discount from middle of year, +Vx-½ or (M x 1.01961) / Dx.] + +By the actuaries' rate we have, with the customary loading for +expense: + + Single premium: $721.66 (loaded, $34.36). Five premiums, $188.70 + (loaded $37.78). Annual premium, $105.65 (loaded $21.11). + +Admitting the correctness of the new method, we must conclude that the +present single premium is not sufficiently loaded to cover its own +expenses, while the annual payment policy pays more than its just +share. A prominent and thoroughly informed life insurance president +says in this connection: "Many of the policies, particularly the short +term endowments, are charged with too high a percentage of expenses to +prove a good investment at maturity or profitable to the insured in +case of surrender." This is not to be wondered at when the applicant +for a 10-year endowment policy sees at a glance that he must pay, in +the gross, more than is returned unless he should die in the interim, +in which case a plain "life" or "term" policy would have answered the +purpose. Under the new system of assessing expenses one form is as +desirable as another, from the standpoint of the insured or the +company. + +The new premium for the 10-year endowment policy, $89.71, commends +itself at once to the applicant, who can easily see that his total +outlay must fall short of the amount ultimately to be realized, of +course, disregarding interest and probable dividends in both cases. + +In discounting the future expense contributions I have not taken the +chances of dying into account. Hence the expense reserve in any +instance applies only to that individual case, and, in the event of +death or surrender before the maturity of the policy, the amount of +the expense fund not used would naturally revert to the insured. + +The scheme of expense assessment outlined above will doubtless be +pronounced impracticable by the majority of insurance men. + +Such a far reaching reform is too much to hope for, at least in the +immediate future. + +No well informed life insurance expert will deny that there are +opportunities for improvement in the business, but to graft new +methods on old companies is a hopeless undertaking. + +It is well, however, to have new methods well matured in advance of +the public demand, and I feel convinced that the ideas here set forth +are in the line of the reform which, before long, must be instituted +by the companies if they would retain the confidence and patronage of +the community. + +Doubtless many insurance presidents could tell of suggestions which +have impressed them favorably and which they would gladly have adopted +were it not for the injustice done thereby to older members and the +changes necessary to bring existing contracts into conformity with the +new system. Similar objections may be urged against the ideas here +advanced, and I must confess I hardly see a way by which the present +suggestions can be utilized by existing companies. We can only hope +that sooner or later some of the new theories may be practically +tested. Meanwhile the companies at present in the field are doing a +great work for the good of humanity, even though their methods may be, +in some particulars, more practical than scientific. + +Winchester, Mass. FRANK J. WILLS. + + * * * * * + + + + +THE FLOOD AT KARLSBAD. + + +During the flood which occurred in Germany and Bohemia, the last week +of November, Karlsbad was especially unfortunate; it suffered such an +inundation as had never before been known in the "Sprudelstadt." On +the evening of November 23, the Tepl was very much swollen by the +rain, which had continued for several days, but it was supposed that +there was no danger of a flood, as the bed of the river had been put +in proper condition. During the forenoon of November 24, the water +suddenly began to rise with such astonishing rapidity that within half +an hour all the lower streets were like turbulent rivers and the Alte +and Neue Wiese were transformed into a lake. The stores on the Alte +Wiese were under water to the roofs, and the proprietors, who were +trying to save their goods, were surprised by the water and had to +take refuge in the trees. They were rescued by having ropes thrown to +them, and during this work a catastrophe occurred which was a great +misfortune to all classes of citizens. The beloved burgermeister of +Karlsbad, Dr. Rudolf Knoll, who had just recovered from a severe +illness, was, with others, directing the work from the balcony of one +of the houses, when a rope by which a man was being drawn through the +water broke, and the man was carried off by the waves. The fright and +excitement of the scene gave the burgermeister a shock which caused +his instant death, but the man who was in danger was brought safely +out of the water. + +The water was 9 ft. in Marienbaderstrasse, the Marktplatz, +Muhlbadgasse, the Sprudelgasse, Kreuzgasse, Kaiserstrasse, and +Egerstrasse, and flooded the quay, causing great destruction. All +places of business were flooded, the doors and iron shutters were +pushed in by the force of the water and the goods were carried away or +ruined. + +The house called "Zum Kaffeebaum" was undermined and part of it fell +to the ground; the same fate was feared for other buildings. The +Sophien and Curhaus bridges were carried away. Other bridges were +greatly damaged, and the masonry along the banks of the river was +partially destroyed. The Sprudelgasse was completely washed out, and +the condition of the Muhlbadgasse was almost as bad. The fire +department with its apparatus had great difficulty in saving the +inhabitants and guests, as there were very few boats or pontoons at +their command, and the soldiers (Pionniere) from Prague and the +firemen from the neighboring towns did not arrive until evening. +Fortunately the water began to fall in the night, and the next day it +had gone down so that it left its terrible work visible. The Sprudel +and the mineral springs were not injured, but, on the other hand, the +water pipes of the bathing establishments and the gas pipes were +completely destroyed.--_Illustrirte Zeitung._ + + * * * * * + + + + +THEATRICAL WATER PLAYS. + + +In one of the plays at Hengler's Circus in London a water scene is +introduced, for which purpose the main ring is flooded with water in a +manner which is both striking and interesting. + +[Illustration: FLOODING A CIRCUS RING.] + +The ring is entirely lined with stout macintosh sheeting, and into +this, from two large conduits. 23,000 gallons of water are poured, the +tank being filled to a depth of some 2 ft. in the remarkably short +time of 35 seconds. A steamboat and other small craft are then +launched and the adventures of the heroine then proceed. She falls +overboard, we believe, but is saved after desperate and amusing +struggles. Our engravings, which are from the _Graphic_, illustrate +the mode of filling the ring with water, and the steamboat launch. + +[Illustration: A THEATRICAL STEAMBOAT.] + + * * * * * + + + + +SCIENCE IN THE THEATER. + + +In the pretty little hall of the Boulevard des Italiens, at Paris, a +striking exhibition of simulated hypnotism is given every evening. + +This entertainment, which has met with much success, was devised by +Mr. Melies, director of the establishment, which was founded many +years ago by the celebrated prestidigitator whose popular name (Robert +Houdin) it still bears. This performance carries instruction with it, +for it shows how easily the most surprising phenomena of the +pathologic state can be imitated. To this effect, several exhibitions +are given every evening. + +Mr. Harmington, a convinced disciple of Mesmer, asks for a subject, +and finds one in the hall. A young artist named Marius presents +himself. Mr. Harmington makes him perform all sorts of extravagant +acts, accompanied with a continuous round of pantomimes that are +rendered the more striking by the supposed state of somnipathy of the +subject. At the moment at which Marius is finishing his most +extraordinary exercises, a policeman suddenly breaks in upon the stage +in order to execute the recent orders relative to hypnotism. But he +himself is subjugated by Mr. Harmington and thrown down by the +vibrations of which the encephalus of this terrible magnetizer is the +center. When the curtain falls, the representative of authority is +struggling against the catalepsy that is overcoming him. + +All the phenomena of induced sleep are successively simulated with +much naturalness by Mr. Jules David, who plays the part of Marius in +this pleasing little performance. + +At a certain moment, after skillfully simulated passes made by the +magnetizer, Mr. David suddenly becomes as rigid as a stick of wood, +and falls in pivoting on his heels (Fig. 1). Did not Mr. Harmington +run to his assistance, he would inevitably crack his skull upon the +floor, but the magnetizer stands just behind him in order to receive +him in his arms. Then he lifts him, and places him upon two chairs +just as he would do with a simple board. He places the head of the +subject upon the seat of one of the chairs and the heels upon that of +the other. Mr. David then remains in a state of perfect immobility. +Not a muscle is seen to relax, and not a motion betrays the +persistence of life in him. The simulation is perfect. + +[Illustration: FIG. 1.--CATALEPTIC RIGIDITY.] + +In order to complete the astonishment of the spectators, Mr. +Harmington seats himself triumphantly upon the abdomen of the subject +and slowly raises his feet and holds them suspended in the air to show +that it is the subject only that supports him, without the need of +any other point of support than the two chairs (Fig. 2). + +[Illustration: FIG. 2.--EXPERIMENT ON THE SAME SUBJECT.] + +Usually, there are plenty of persons ingenuous enough to think that +Mr. David is actually in a cataleptic sleep, one of the characters of +which is cadaveric rigidity. + +As Mr. David's neck is entirely bare, it is not possible to suppose +that the simulator of catalepsy wears an iron corset concealed beneath +his clothing. He has performed a feat of strength and skill rendered +easy by the exercise that he has given to the muscles occupying the +_colliciæ_ of his vertebral column. This part of the muscular system +is greatly developed in the weakest and least hardy persons. In fact, +in order that man may keep a vertical position and execute an infinite +multitude of motions in which stability is involved, nature has had to +give him a large number of different organs. The muscles of the back +are arranged upon several superposed layers, the vertebral column is +doubly recurved in order that it may have more strength, and, finally, +rachidion nerves issue from each vertebra in order to regulate the +contraction of each muscular fasciculus according to the requirements +of equilibrium. The trick is so easy that we have seen youths +belonging to the Ligue d'Education Physique immediately imitate Mr. +David after seeing him operate but once. + +For the sake of those who would like to perform it, we shall add that +Mr. David takes care to bend his body in the form of an arch in such a +way that the convexity shall be beneath. As Mr. Harmington never fails +to place himself in the center of the line that joins Mr. David's head +and heels, his weight is divided into two parts, that is to say, 88 +pounds on each side of the point of support. The result is that the +stress necessary is less than that of a strong man of the Halle +lifting a bag of wheat to his shoulder or of an athlete supporting a +human pyramid. The force of contraction of the muscular fibers brought +into play in this experiment is much greater than is commonly +believed. In his lectures on physiology, Milne-Edwards cites some +facts that prove that it may exceed 600 pounds per square inch of +section. + +[Illustration: FIG. 3.--THE PERFORATE ARM.] + +The experiment on cadaveric rigidity is followed by others in +insensibility. Mr. David, without wincing, allows a poignard to be +thrust into his arm, which Mr. Harmington has previously +"cataleptized" (Fig. 3). This trick is performed by means of a blade +divided into two parts that are connected by a semicircle. This +process is well known to prestidigitators, but it might be executed in +a genuine manner. In fact, on replacing the poignard by one of the +gold needles used by physicians for acupuncture, it would be possible +to dispense with prestidigitation. Under such conditions it is +possible to transpierce a person's arm. The pain is supportable, and +consists in the sensation of a prick produced in the passage of the +needle through the skin. As for the muscular flesh, that is of itself +perfectly insensible. The needle, upon the necessary antiseptic +precautions being taken, may traverse the veins and arteries with +impunity, provided that it is not allowed to remain long enough to +bring about the formation of a clot of coagulated blood (Fig. 4). + +[Illustration: FIG. 4.--AN ARM TRANSPIERCED BY A NEEDLE.] + +We think it of interest to add that it is necessary that the +experiment be performed by a practitioner if one desires to +demonstrate upon himself a very curious physiological fact that has +been known from the remotest antiquity. It has been employed for +several thousand years in Chinese medicine, for opening a passage for +the bad spirits that produce diseases. For some years past a much more +serious use has been made of it in European medicine for introducing +electric currents into the interior of the organism. In this case the +perimeter of the needle is insulated, and the electricity flows into +the organism through the point. We have several times had these +operations performed upon ourselves, and this permits us to assert +that the above mentioned facts are absolutely true.--_La Nature._ + + * * * * * + + + + +NEWER PHYSIOLOGY AND PATHOLOGY. + +By Prof. SAMUEL BELL, M.D. + + +Physiology has for many decades been a science founded on experiment, +and pathology has been rapidly pressing forward in the same direction. +To read the accounts of how certain conclusions have been arrived at +in the laboratory, by ingenious devices and by skillful manipulations, +is as fascinating as any tale of adventure. + +When the microscope began its work, how discouraging was the vastness +and complexity of the discoveries which it brought to light; how many +years has it been diligently used, and how uncertain are we still +about many of its revelations! But what a happy conjecture of man, and +as proper environment takes place we may reach better results! Let me +give an illustration: + +Some thirty years ago, Virchow began his studies and lectures upon +cellular pathology. The enthusiasm which he awakened spread over the +whole medical world. The wonderful attention to detail, the broad +philosophy which signalized his observations, were alike remarkable. +His class room was packed with students from every country, who +thought it no hardship to struggle for a seat at eight o'clock in the +morning. With his blackboard behind him and specimens of pathology +before him, and microscopes coursing upon railway tracks around the +tables which filled the room, he was the embodiment of the teacher; +his highest honor was as discoverer. The life and importance of the +cell, both in health and disease, it has been his work to discover and +to teach. The point of view from which he has classified tumors is +founded on this basis, and remains the accepted method. The light +which he cast upon the nature of inflammation has not yet been +obscured, and while other phenomena appear, the multiplication of +cells and nuclei and the formation of connective tissue in the process +of inflammation will always call to mind his labors. + +To one of Virchow's pupils, Prof. Recklinghausen, we chiefly owe our +knowledge of the phenomena of diapedesis as a part of the inflammatory +activity. How incredible it seems that masses of living matter can +make their way through the walls of blood vessels which do not rupture +and which have no visible apertures! + +Virchow fixed his attention upon the forms and activities of the +cells, their multiplication and degradation, and how they build up +tissues, both healthy and morbid. + +To another matter with which, both literally and metaphorically, the +air is filled, we must also make allusion. The existence of +micro-organisms in countless numbers is no new fact, but the influence +they may exert over living tissues has only lately become the subject +of earnest attention. So long as they were not known to have any +practical bearing upon human welfare, they interested almost nobody, +but when, however, it was shown that putrefaction of meat is due to +the agency of the _bacterium termo_, and the decomposition of albumen +to the _bacillus subtilis_; when anthrax in cattle and sheep was found +to depend on the _bacillus anthracis_, and that in human beings it +caused malignant pustules; when suppuration of wounds was found to be +associated with micrococci; and when it was announced that by a +process of inoculation cattle could be protected against anthrax, and +that by carbolic spray and other well known precautions the +suppuration of wounds could be prevented--all the world lent its ears +and investigation at once began. + +Because labors in bacteriology promised to be fruitful in practical +results, the workers speedily became innumerable, and we are +accumulating a wondrous store of facts. How long now is the list of +diseases in which germs make their appearance--in pneumonia, in +endocarditis, in erysipelas, in pyæmia, in tuberculosis, and so on and +so on. One of the most striking illustrations is the gonococcus of +gonorrhoea, whose presence in and around gives to the pus cells +their virulent properties, and when transferred to the eye works such +lamentable mischief. Without their existence the inoculation of pus in +the healthy eye is harmless; pus bearing the gonococci excites the +most intense inflammation. Similar suppurative action in the cornea is +often caused by infection of cocci. The proof of causation may be +found in the fact that the most effective cure now practiced for such +suppuration is to sterilize them by the actual cautery. Rosenbach says +that he knows six distinct microbes which are capable of exciting +suppuration in man. Their activity may be productive of a poison, or +putrefactive alkaloid, which is absorbed. + +There are at present two prominent theories in regard to the +infections which produce disease. The first is based upon chemical +processes, the second upon the multiplication of living organisms. The +chemical theory maintains that after the infectious element has been +received into the body it acts as a ferment, and gives rise to certain +morbid processes, upon the principle of catalysis. The theory of +organisms, or the germ theory, maintains that the infectious elements +are living organisms, which, being received into the system, are +reproduced indefinitely, and excite morbid processes which are +characteristic of certain types of disease. This latter theory so +readily explains many of the facts connected with the development and +reproduction of infectious diseases, that it has been unqualifiedly +adopted by a large number of investigators. The proofs of this theory +had not, however, advanced beyond the demonstrations of the presence +of certain forms of bacteria in the pathological changes of a very +limited number of infectious diseases, until February, 1882, when Koch +announced his discovery of the tubercle bacillus, since which time +nearly every disease has its supposed microbe, and the race is, +indeed, swift in which the would-be discoverers press forward with new +germs for public favor. + +The term bacteria or microbe refers to particles of matter, +microscopic in size, which belong to the vegetable kingdom, where they +are known as fungi. If we examine a drop of stagnant water under the +microscope, amplifying say four hundred diameters, we see it loaded +with minute bodies, some mere points, others slightly elongated into +rods, all actively in motion and in various positions, a countless +confusion. If evaporation now takes place, all is still. If we now +apply moisture, the dried-up granules will show activity, as though +they had not been disturbed. + +All these different organisms have become familiar to us under the +generic term bacteria, which is a very unfortunate application, as it +really applies to only a single class of fungi. Cohn calls them +schizomycetes, and makes the following classifications: + + 1. _Sphero-bacteria_, or microbes. + 2. _Micro-bacteria_, or bacteria. + 3. _Desmo-bacteria_, or bacilli. + 4. _Spiroteria_, or spirillæ. + +The _spiro-bacteria_, or micrococci, are the simplest of the fungi, +and appear as minute organisms of spherical form. They multiply by +fission, a single coccus forming two, these two producing four, and so +on. They present a variety of appearances under the microscope. From +single isolated specimens (which under the highest magnifying power +present nothing beyond minute points) you will observe them in pairs, +again in fours, or in clusters of hundreds (forming zoöglea) and still +adhering together, forming chains. When a given specimen is about to +divide, it is seen to elongate slightly, then a constriction is +formed, which deepens until complete fission ensues. + +Micrococci possess no visible structure. They consist of a minute +droplet of protoplasm (mycroprotein) surrounded by a delicate cell +membrane. Certain forms are embedded in a capsule (diameter 0.0008 to +0.0001 millimeter). + +These little organisms, when observed in a fluid like blood, sputum, +etc., are found to present very active movements, although provided +with no organs of locomotion. + +This Brownian motion is possessed by almost every minute particle of +matter, organic and inorganic, and is not due to any inherent power of +the individual. They are almost omnipresent, abounding in the air, the +earth, the water, are always found in millions where moist organic +matter is undergoing decomposition, and are associated with the +processes of fermentation--in fact, they are essential to it. The +souring of milk succeeds the multiplication of these germs. Certain +varieties are pigmented, and we observe colonies of chromogenic cocci +multiplying upon slices of boiled potato, eggs, etc., presenting all +the colors of the rainbow. All of these germs are not the cause of +disease. Certain species, however (termed pathogenic), are always +associated with certain diseased conditions. + +The _bacteria-termo_--micro-bacteria--are slightly elongated, and +inasmuch as they multiply by division, frequently appear coupled +together, linked in pairs, and in chains. They are generally found in +putrefying liquids, especially infusions of vegetable matter. They +possess mobility to a remarkable degree. Observing a field of +bacteria-termo under the microscope, they may be seen actively engaged +in twining and twisting. A flagellum has been demonstrated as attached +to one or both extremities. This is too minute to be generally +resolved, even if it is a common appendage. + +_Desmo-bacteria_ (or bacilli) are rod-like organisms, occurring of +various lengths and different thicknesses. In a slide of the bacillus +of tuberculosis and anthrax, we notice at intervals dots which +represent the spores from which, as the rods break up, future bacilli +are developed. + +Then we have _spiro-bacteria,_ the spirilla and the spirochetæ; the +former having short open spirals, the latter long and closely wound +spirals. The _spirillum, volutans_ is often found in drinking water, +and in common with some other specimens of this class is provided with +flagellæ, sometimes at both extremities, which furnish the means of +rapid locomotion. The spiro-bacteria multiply by spores, although +little is at present known of their life history. They frequently are +attached together at their extremities, forming zigzag chains. + +We have seen that bacteria differ greatly in appearance from the +elongated dot of the bacterium proper, to the elongated rod or +cylinder of the bacillus, and the long spirals of spiro-bacteria. It +is unfortunate that they are not sufficiently constant in habit to +always attach themselves to one or the other of these genera. The +micrococcus has a habit of elongating at times until it is impossible +to recognize him except as a bacterium; while bacilli, again, break up +until their particles exactly resemble micrococci. + +Bacteria cannot exist without water; certain forms require oxygen, +while others thrive equally well without it; some thrive in solution +of simple salts, while others require albuminoid material. + +Bacteriology, with its relation to the science of medicine, is of +importance to every investigating physician; it covers our knowledge +of the relation of these minute organisms to the ætiology of disease. +What has been gained as to practical application in the treatment of +disease? This question is not infrequently asked in a sneering manner. +We can, in reply, say that the results are not all in the future. It +is encouraging that results have been attained which have had a very +important practical bearing, and that these complaints come generally +from individuals least acquainted with scientific investigations in +bacteriology. + +In the study of the relation of a given bacterium to a certain +disease, it becomes necessary to attend carefully to three different +operations: First, the organism supposed to cause the disease must be +found and isolated. Second, it must be cultivated through several +generations in order that absolute purity may be secured. Lastly, the +germ must be again introduced into a healthy living being. If the +preceding steps be carried out, and the original disease be +communicated by inoculation, and the germs be again found in the +diseased body, we have no alternative; we must conclude that we have +ascertained the cause of the disease. The importance of being familiar +with the ætiology of the disease before we can expect to combat it +with any well-grounded hope of success is evident. + +If the sputum of a phthisical patient be submitted to the skilled +microscopist, he is nearly always able to demonstrate bacilli, but +this goes for very little. Because bacilli are found in phthisis, it +is no more certain that they are the cause of phthisis than it is +certain that cheese mites are the cause of cheese. Well, suppose we +were to inject sputum from a phthisical person into the lower animal +and tuberculosis follows, and then announce to the profession that we +have demonstrated the relation of the cause and effect between bacilli +and phthisis? Why we would start such an uproar of objections as would +speedily convince us that there was much work yet in the domain of +bacteriology. + +The scientific investigators would say you have injected with the +sputum into the blood of your unfortunate patient, pus, morphological +elements, and perhaps half a dozen other forms of bacteria, any one of +which is just as likely to produce the disease as the bacillus you +have selected. + +The first important step is, first isolate your bacillus. If I were to +take a glass plate, one side of which is coated with a thick solution +of peptonized gelatin, and allow the water to collect, the gelatinous +matter will become solid. If now, with a wire dipped in some +tuberculous matter, I draw a line along the gelatin, I have deposited +at intervals along this line, specimens of tubercle bacilli. If this +plate be now kept at a proper temperature, after a few days, wherever +the bacilli have been caught, a grayish spot will appear, which, +easily seen with the naked eye, gradually spreads and becomes larger. +These spots are colonies containing thousands of bacilli. Let us +return to our gelatin plate. + +We find a spot which answers to the description of a colony of +tubercle bacilli. We now take a minute particle from this colony on a +wire and convey it to the surface of some hardened blood serum in a +test tube. We plug the tube so that no air germs may drop in, and +place it in an incubator at the proper temperature. After several +days, if no contamination be present, a colony of bacilli will appear +around the spot where we sowed the spores. Let us repeat the process. + +Take a particle from this colony, and transfer it to another tube. +This is our second culture. This must be repeated until we are +satisfied that we have secured a _pure_ culture. If this be carried to +the twenty-fifth generation, we may be assured that there remains no +pus, no ptomaines, nothing but the desired bacilli. + +It is a proper material now for inoculation, and if we inoculate some +of the lower animals, for instance the monkey, we produce a disease +identical with phthisis pulmpnalis. Bacteria also afford peculiar +chemical reactions. For example, nitric acid will discharge all the +color from all bacilli artificially dyed with anilin, except those of +tubercle and anthrax. One species is stained readily with a dye that +leaves another unaltered. Thus we are enabled in the laboratory to +determine whether the bacilli found in sputum, for example, are from +tubercle or are the bacteria of decomposition. + +From what I have said of the tubercle bacillus, it would seem +thoroughly demonstrated that it is the cause of tubercle in these +animals. But we must walk cautiously here. These are not human beings, +who know that like results would follow their inoculation. The animals +used by Koch are animals very subject to tubercle. + +We must, from the very nature of our environment, be constantly +inhaling these germs as we pass through the wards of our hospitals; +yes, they are floating in the air of our streets and dwellings. It +becomes necessary then for us to inquire: If bacteria cause disease, +in what manner do they produce it? The healthy organism is always +beset with a multitude of non-pathogenic bacteria. They occupy the +natural cavities, especially the alimentary canal. They feed on the +substances lying in their neighborhood, whether brought into the body +or secreted by the tissues. In so doing they set up chemical changes +in their substances. Where the organs are acting normally these fungi +work no mischief. The products of decomposition thus set up are +harmless, or are conveyed out of the body before they begin to be +active. + +If bacteria develop to an inordinate degree, if the contents of organs +are not frequently discharged, fermentative processes may be set up, +which result in disease. Bacteria must always multiply and exist at +the expense of the body which they infest, and the more weakened the +vital forces become, the more favorable is the soil for their +development. + +Septicæmia is caused by the absorption of the products of +putrefaction, induced before bacteria can multiply inside or outside +the body. Bacteria must find a congenial soil. The so-called cholera +bacillus must gain access to the intestinal tract before it finds +conditions suitable to colonization. It does not seem to multiply in +the stomach or in the blood, but once injected into the duodenum +develops with astonishing rapidity, and the delicate epithelial cells +of the villi become swollen, soften and break down, exposing the +mucosa. + +It has been shown that _bouillon_ in which Loeffler's diphtheria +bacillus has grown, and which has been passed through unglazed +porcelain filters, shows the presence of a poison which is capable of +producing the same results upon inoculation as the pure culture of the +bacillus itself. Zarniko, working upon the same organism, obtained a +number of positive results that led him to declare this bacillus is +the cause of epidemic diphtheria, in spite of many assertions to the +contrary. Chantmesse and Widal record the results of their work as to +what will most easily and effectively destroy the bacillus of +diphtheria. + +The only three substances that actually checked and destroyed its +vitality were phenic acid (5 per cent.), camphor (20 per cent.), olive +oil (25 per cent.), in combination. For the last I substitute +glycerine, because this allows the mixture to penetrate farther into +the mucous membrane than oil, the latter favoring a tendency to pass +over the surface. This mixture when heated separates into two layers, +the upper one viscid and forming a sort of "glycerol," the lower +clear. The latter will completely sterilize a thread dipped in a pure +culture of the diphtheria bacillus. Corrosive sublimate was not +examined because in strong enough doses it would be dangerous and in +weaker ones it would be useless. + +The facts obtained in regards to the streptococcus of erysipelas are +reported as follows: That both chemical and experimental evidence +teach the extreme ease of a renewed attack of the disease; that it is +possible to kill guinea pigs by an intoxication when they are immune +to an inoculation of the culture in ordinary quantities. And this +latter fact should warn experimenters trying to obtain immunity in man +by the inoculation of non-pathogenic bacteria, because the same +results may be reached. + +A new theory in regard to fevers and the relation of micro-organisms +is suggested by Roussy, viz.: That it is a fermentation produced by a +diastase or soluble ferment found in all micro-organisms and cells, +and which they use in attacking and transforming matter, either inside +their substance or without it. + +The resemblance of the malaria parasite to that of recurrent fever is +noted in the work of Sacharoff. He states that there exists in the +blood of those suffering from recurrent fever a hæmatozoon, which is +most prominent after the fever has begun to fall, when it is of +enormous proportions, twenty or more diameters of a red blood +corpuscle, although smaller ones may still be found. The parasite +consists of a delicate amoeboid body containing a multitude of dark, +round, uniform, sharply outlined, movable granules. Besides these, the +protoplasm contains a generally grayish homogeneous nucleus as large +as one or two red blood corpuscles. The protoplasm sends out +pseudopodia (with granules), which sometimes separate and appear as +small delicate pieces of protoplasm. They vary in size, and are often +swallowed by the red blood corpuscles in which they grow, and finally +develop into the above mentioned amoeboid bodies. + +Prof. J. Lewis Smith has made a great many autopsies of children dead +from cholera infantum, and almost invariably found the stomach and +liver in a comparatively healthy condition. Ganghen, who has given +this subject considerable study, denies the existence of any specific +germ in the summer diarrhea of infants, but claims to have found three +different germs in the intestines of children suffering from cholera +infantum, each producing a chemical poison which is capable of +producing vomiting, purging, and even death. A great variety of germs +are found in drinking water, and no doubt countless numbers are taken +into the digestive tract, and the principal reason why pathological +conditions do not occur more frequently is on account of the +germicidal qualities of the gastric juice. + +The comma bacillus of Koch, and the typhoid fever germ of Eberth, are +especially destroyed in normal gastric juice. When the germs are very +numerous, they run the gauntlet of the stomach (as the gastric juice +is secreted only during digestion); and once in the alkaline +intestinal canal they are capable of setting up disease, other +conditions contributing--ill health, deranged digestion, etc. + +Mittnam has made a study of bacteria beneath the nails, and reports, +after examining persons following different occupations, having found +numerous varieties of micro-organisms; which are interesting from a +scientific standpoint relative to the importance of thoroughly +cleansing the hands before undertaking any surgical procedure. He +found, out of twenty-five experiments, 78 varieties of bacteria, of +which 36 were classed as micrococci, 21 diplococci, 18 rods, 3 +sarcinæ, and 1 yeast. Cooks, barbers, waiters, etc., were examined. + +The blood, defibrinated and freshly drawn, has marked germicidal +action; for bacteria its action is decidedly deadly, even hours after +it has been drawn from the body. Especially were anti-germic qualities +noticed upon pathogenic bacteria. Buchner put the bacilli of anthrax +in a quantity of blood, and in two hours the number was reduced from +4,800 to 56, and in three hours only 3 living bacteria remained. Other +bacteria were experimented upon in blood with similar results, but the +destruction of the organism from putrefaction was much less marked, +and on some varieties the blood had little or no action. + +It is not the object of these remarks to even give a _résumé_ of the +_status præsens_ of bacteriology, but simply to stimulate thought in +that direction. The claims of some of the ultra-bacteriologists may +never be realized, but enough has been accomplished to revolutionize +the treatment of certain diseases, and the observing student will do +well to keep his eye on the microbe, as it seems from the latest +investigations that its star is in the ascendant. And who can +prognosticate but that in the next decade an entire revolution in the +ætiology and treatment of many diseases may take place? + +Detroit, Mich. + + * * * * * + + + + +THE COMPOSITION OF KOCH'S LYMPH. + +WHAT PROFESSOR KOCH SAYS IT IS, AND WHAT IT CAN DO. + +(By Cable to the _Medical Record_.) + +BERLIN, January 15, 1891. + + +The curiosity to know the composition of the famous lymph has been +gratified by the publication to-day of an article by Professor Koch on +the subject. In the following, as will be seen, he reaffirms his +original convictions and acknowledges the valuable assistance he has +received from those who have used his fluid, and thus helped him in +the accumulation of experience. + +Professor Koch says: Two months ago I published the results of my +experiments with the new remedy for tuberculosis, since which time +many physicians who received the preparation have been enabled to +become acquainted with its properties through their own experiments. +So far as I have been able to review the statements published and the +communications received by letter, my predictions have been fully and +completely confirmed. The general consensus of opinion is that the +remedy has a specific action upon tubercular tissues, and is, +therefore, applicable as a very delicate and sure reagent for +discovering latent and diagnosing doubtful tuberculous processes. +Regarding the curative effects of the remedy, most reports agree that, +despite the comparatively short duration of its application, many +patients have shown more or less pronounced improvement. It has been +affirmed that in not a few cases even a cure has been established. +Standing quite by itself is the assertion that the remedy may not only +be dangerous in cases which have advanced too far--a fact which may +forthwith be conceded--but also that it actually promotes the +tuberculous process, being therefore injurious. + +During the past six weeks I myself have had opportunity to bring +together further experiences touching the curative effects and +diagnostic application of the remedy in the cases of about one hundred +and fifty sufferers from tuberculosis of the most varied types in this +city and in the Moabit Hospital. + +I can only say that everything I have latterly seen accords with my +previous observations. There has been nothing to modify in what I +before reported. As long as it was only a question of proving the +accuracy of my indications, it was needless for any one to know what +the remedy contained or whence it was derived. On the contrary, +subsequent testing would necessarily be more unbiased, the less people +knew of the remedy itself. Now, after sufficient confirmatory testing, +the importance of the remedy is proved, my next task is to extend my +study of the remedy beyond the field where it has hitherto been +applied, and if possible to apply the principle underlying the +discovery to other diseases. + +This task naturally demands a full knowledge of the remedy. I +therefore consider that the time has arrived when the requisite +indications in this direction shall be made. This is done in what +follows. + +Before going into the remedy itself, I deem it necessary for the +better understanding of its mode of operation to state briefly the way +by which I arrived at the discovery. If a healthy guinea pig be +inoculated with the pure cultivation of German Kultur of tubercle +bacilli, the wound caused by the inoculation mostly closes over with a +sticky matter, and appears in its early days to heal. Only after ten +to fourteen days a hard nodule presents itself, which, soon breaking, +forms an ulcerating sore, which continues until the animal dies. Quite +a different condition of things occurs when a guinea pig already +suffering from tuberculosis is inoculated. An animal successfully +inoculated from four to six weeks before is best adapted for this +purpose. In such an animal the small indentation assumes the same +sticky covering at the beginning, but no nodules form. On the +contrary, on the day following, or the second day after the +inoculation, the place where the lymph is injected shows a strange +change. It becomes hard and assumes a darker coloring, which is not +confined to the inoculation spot, but spreads to the neighboring parts +until it attains a diameter of from 0.05 to 1 cm. + +In a few days it becomes more and more manifest that the skin thus +changed is necrotic, finally falling off, leaving a flat ulceration +which usually heals rapidly and permanently without any involvement of +the adjacent lymphatic glands. Thus the injected tubercular bacilli +quite differently affect the skin of a healthy guinea pig from one +affected with tuberculosis. This effect is not exclusively produced +with living tubercular bacilli, but is also observed with the dead +bacilli, the result being the same whether, as I discovered by +experiments at the outset, the bacilli are killed by a somewhat +prolonged application of a low temperature or boiling heat or by means +of certain chemicals. This peculiar fact I followed up in all +directions, and this further result was obtained--that killed pure +cultivations of tubercular bacilli, after rinsing in water, might be +injected in great quantities under healthy guinea pig's skin without +anything occurring beyond local suppuration. Such injections belong to +the simplest and surest means of producing suppurations free from +living bacteria. + +Tuberculous guinea pigs, on the other hand, are killed by the +injection of very small quantities of such diluted cultivations. In +fact, within six to forty-eight hours, according to the strength of +the dose, an injection which is not sufficient to produce the death of +the animal may cause extended necrosis to the skin in the vicinity of +the place of injection. If the dilution is still further diluted until +it is scarcely visibly clouded, the animals inoculated remain alive +and a noticeable improvement in their condition soon supervenes. If +the injections are continued at intervals of from one to two days, the +ulcerating inoculation wound becomes smaller and finally scars over, +which otherwise it never does; the size of the swollen lymphatic +glands is reduced, the body becomes better nourished, and the morbid +process ceases, unless it has gone too far, in which case the animal +perishes from exhaustion. By this means the basis of a curative +process against tuberculosis was established. + +Against the practical application of such dilutions of dead tubercle +bacilli there presented itself the fact that the tubercle bacilli are +not absorbed at the inoculation points, nor do they disappear in +another way, but for a long time remain unchanged, and engender +greater or smaller suppurative foci. Anything, therefore, intended to +exercise a healing effect on the tuberculous process must be a soluble +substance which would be liberated to a certain extent by the fluids +of the body floating around the tubercle bacilli, and be transferred +in a fairly rapid manner to the juices of the body; while the +substance producing suppuration apparently remains behind in the +tubercular bacilli, or dissolves but very slowly. The only important +point was, therefore, to induce outside the body the process going on +inside, if possible, and to extract from the tubercular bacilli alone +the curative substance. This demanded time and toil, until I finally +succeeded, with the aid of a forty to fifty per cent. solution of +glycerine, in obtaining an effective substance from the tubercular +bacilli. With the fluid so obtained I made further experiments on +animals, and finally on human beings. These fluids were given to other +physicians to enable them to repeat the experiments. + +The remedy which is used in the new treatment consists of a glycerine +extract, derived from the pure cultivation of tubercle bacilli. Into +the simple extract there naturally passes from the tubercular bacilli, +besides the effective substance, all the other matter soluble in fifty +per cent. glycerine. + +Consequently, it contains a certain quantity of mineral salts, +coloring substances, and other unknown extractive matters. Some of +these substances can be removed from it tolerably easily. The +effective substance is insoluble in absolute alcohol. It can be +precipitated by it, though not, indeed, in a pure condition, but still +combined with the other extractive matter. It is likewise insoluble in +alcohol. The coloring matter may also be removed, rendering it +possible to obtain from the extract a colorless, dry substance +containing the effective principle in a much more concentrated form +than the original glycerine solution. For application in practice this +purification of the glycerine extract offers no advantage, because the +substances so eliminated are unessential for the human organism. The +process of purification would make the cost of the remedy +unnecessarily high. + +Regarding the constitution of the more effective substances, only +surmises may for the present be expressed. It appears to me to be +derivative from albuminous bodies, having a close affinity to them. It +does not belong to the group of so-called toxalbumins, because it +bears high temperatures, and in the dialyzer goes easily and quickly +through the membrane. The proportion of the substance in the extract +to all appearance is very small. It is estimated at fractions of one +per cent., which, if correct, we should have to do with a matter whose +effects upon organisms attacked with tuberculosis go far beyond what +is known to us of the strongest drugs. + +Regarding the manner in which the specific action of the remedy on +tuberculous tissue is to be represented, various hypotheses may +naturally be put forward. Without wishing to affirm that my view +affords the best explanation, I represent the process myself in the +following manner: + +The tubercle bacilli produced when growing in living tissues, the same +as in artificial cultivations, contain substances which variously and +notably unfavorably influence living elements in their vicinity. Among +these is a substance which in a certain degree of concentration kills +or so alters living protoplasm that it passes into a condition that +Weigert describes as coagulation necrosis. In tissue thus become +necrotic the bacillus finds such unfavorable conditions of nourishment +that it can grow no more and sometimes dies. + +This explains the remarkable phenomenon that in organs newly attacked +with tuberculosis, for instance in guinea pigs' spleen and liver, +which then are covered with gray nodules, numbers of bacilli are +found, whereas they are rare or wholly absent when the enormously +enlarged spleen consists almost entirely of whitish substance in a +condition of coagulation necrosis, such as is often found in cases of +natural death in tuberculous guinea pigs. The single bacillus cannot, +therefore, induce necrosis at a great distance, for as soon as +necrosis attains a certain extension the growth of the bacillus +subsides, and therewith the production of the necrotizing substance. A +kind of reciprocal compensation thus occurs, causing the vegetation of +isolated bacilli to remain so extraordinarily restricted, as, for +instance, in lupus and scrofulous glands. + +In such cases the necrosis generally extends only to a part of the +cells, which then, with further growth, assume the peculiar form of +riesen zelle, or giant cells. Thus, in this interpretation, follow +first the explanation Weigert gives of the production of giant cells. + +If now one increased artificially in the vicinity of the bacillus the +amount of necrotizing substance in the tissue, the necrosis would +spread a greater distance. The conditions of nourishment for the +bacillus would thereby become more unfavorable than usual. + +In the first place the tissue which had become necrotic over a large +extent would decay and detach itself, and where such were possible +would carry off the inclosed bacilli and eject them outwardly, so far +disturbing their vegetation that they would much more speedily be +killed than under ordinary circumstances. + +It is just in looking at such changes that the effect of the remedy +appears to consist. It contains a certain quantity of necrotizing +substance, a correspondingly large dose of which injures certain +tissue elements even in a healthy person, and perhaps the white blood +corpuscles or adjacent cells, thereby producing fever and a +complication of symptoms, whereas with tuberculous patients a much +smaller quantity suffices to induce at certain places, namely, where +tubercle bacilli are vegetating and have already impregnated the +adjacent region with the same necrotizing matter, more or less +extensive necrosis of the cells, with the phenomena in the whole +organism which result from and are connected with it. + +For the present, at least, it is impossible to explain the specific +influence which the remedy, in accurately defined doses, exercises +upon tuberculous tissue, and the possibility of increasing the doses +with such remarkable rapidity, and the remedial effects which have +unquestionably been produced under not too favorable circumstances. + +Of the consumptive patients whom he described as temporarily cured, +two have been returned to the Moabit Hospital for further observation. + +No bacilli have appeared in their sputum for the past three months, +and their phthisical symptoms have gradually and completely +disappeared. + + * * * * * + + + + +CAN WE SEPARATE ANIMALS FROM PLANTS? + +By ANDREW WILSON. + + +One of the plainest points connected with the study of living things +is the power we apparently possess of separating animals from plants. +So self-evident appears this power that the popular notion scoffs at +the idea of science modestly disclaiming its ability to separate the +one group of living beings from the other. Is there any danger of +confusing a bird with the tree amid the foliage of which it builds its +nest, or of mistaking a cow for the grass it eats? These queries are, +of course, answerable in one way only. Unfortunately (for the +querists), however, they do not include or comprehend the whole +difficulty. They merely assert, what is perfectly true, that we are +able, without trouble, to mark off the higher animals from the higher +plants. What science inquires is, whether we are able to separate +_all_ animals from _all_ plants, and to fix a definite boundary line, +so as to say that all the organisms on the one side of the line are +assuredly animals, while all the others on the opposite side of the +line may be declared to be truly plants. It is exactly this task which +science declares to be among the impossibilities of knowledge. Away +down in the depths of existence and among the groundlings of life the +identity of living things becomes of a nature which is worse than +confusing, and which renders it a futile task to attempt to separate +the two worlds of life. The hopelessness of the task, indeed, has +struck some observers so forcibly that they have proposed to +constitute a third kingdom--the _Regnum Protisticum_--between the +animal and the plant worlds, for the reception of the host of doubtful +organisms. This third kingdom would resemble the casual ward of a +workhouse, in that it would receive the waifs and strays of life which +could not find a refuge anywhere else. + +A very slight incursion into biological fields may serve to show forth +the difficulties of naturalists when the task of separating animals +from plants is mooted for discussion. To begin with, if we suppose our +popular disbeliever to assert that animals and plants are always to be +distinguished by shape and form, it is easy enough to show him that +here, as elsewhere, appearances are deceptive. What are we to say of a +sponge, or a sea anemone, of corals, of zoophytes growing rooted from +oyster shells, of sea squirts, and of sea mats? These, each and all of +them, are true animals, but they are so plant-like that, as a matter +of fact, they are often mistaken by seaside visitors for plants. This +last remark holds especially true of the zoophytes and the sea mats. +Then, on the other hand, we can point to hundreds of lower plants, +from the yeast plant onward, which show none of the ordinary features +of plant life at all. They possess neither roots, stems, branches, +leaves, nor flowers, so that on this first count of the indictment the +naturalist gains the day. + +Power of movement, to which the popular doubter is certain to appeal, +is an equally baseless ground of separation. For all the animals I +have above named are rooted and fixed, while many true plants of lower +grade are never rooted at all. The yeast plant, the _Algæ_ that swarm +in our ponds, and the diatoms that crowd the waters, exemplify plants +that are as free as animals; and many of them, besides, in their young +state especially (e.g., the seaweeds), swim about freely in the water +as if they were roving animalcules. On the second count, also, science +gains the day; power of motion is no legitimate ground at all for +distinguishing one living being as an animal, while absence of +movement is similarly no reason for assuming that the fixed organism +must of necessity be a plant. Then comes the microscopic evidence. +What can this wonder glass do in the way of drawing boundary lines +betwixt the living worlds? The reply again is disappointing to the +doubter; for the microscope teaches us that the tissues of animals and +plants are built upon kindred lines. We meet with cells and fibers in +both. The cell is in each case the primitive expression of the whole +organism. Beyond cells and fibers we see the wonderful living +substance, _protoplasm_, which is alike to our senses in the two +kingdoms, although, indeed, differing much here and there in the +results of its work. On purely microscopic grounds, we cannot separate +animals from plants. There is no justification for rigidly assuming +that this is a plant or that an animal on account of anything the +microscope can disclose. A still more important point in connection +with this protoplasm question consists in the fact that as we go +backward to the beginnings of life, both in animals and plants, we +seem to approach nearer and nearer to an identity of substance which +baffles the microscope with all its powers of discernment. Every +animal and every plant begins existence as a mere speck of this living +jelly. The germ of each is a protoplasm particle, which, whatever +traces of structure it may exhibit, is practically unrecognizable as +being definitely animal or plant in respect of its nature. Later on, +as we know, the egg or germ shows traces of structure in the case of +the higher animals and plants; while even lowly forms of life exhibit +more or less characteristic phases when they reach their adult stage. +But, of life's beginnings, the microscope is as futile as a kind +scientific touchstone for distinguishing animals from plants as is +power of movement, or shape, or form. + +A fourth point of appeal in the matter is found within the domain of +the chemist. Chemistry, with its subtile powers of analysis, with its +many-sided possibilities of discovering the composition of things, and +with its ability to analyze for us even the light of the far distant +stars, only complicates the difficulties of the biologist. For, while +of old it was assumed that a particular element, nitrogen, was +peculiar to animals, and that carbon was an element peculiar to +plants, we now know that both elements are found in animals, just as +both occur in plants. The chemistry of living things, moreover, when +it did grow to become a staple part of science, revealed other and +greater anomalies than these. It showed that certain substances which +were supposed to be peculiar to plants, and to be made and +manufactured by them alone, were also found in animals. Chlorophyl is +the green coloring matter of plants, and is, of course, a typical +product of the vegetable world; yet it is made by such animals as the +hydra of the brooks and ponds, and by many animalcules and some worms. +Starch is surely a typical plant product, yet it is undoubtedly +manufactured, or at least stored up, by animals--a work illustrated by +the liver of man himself, which occasionally produces sugar out of its +starch. + +Again, there is a substance called _cellulose_, found well nigh +universally in plants. Of this substance, which is akin to starch, the +walls or envelopes of the cells of plant tissues are composed. Yet we +find those curious animals, the sea squirts, found on rocks and stones +at low-water mark, manufacturing cellulose to form part and parcel of +the outer covering of their sac-like bodies. Here it is as if the +animal, like a dishonest manufacturer, had infringed the patent rights +of the plant. On the fourth count, then--that of chemical +composition--the verdict is that nothing that chemistry can teach us +may serve definitely, clearly, and exactly to set a boundary line or +to erect a partition wall between the two worlds of life. There yet +remains for us to consider a fifth head--that of the food. + +In the matter of the feeding of the two great living worlds we might +perchance light upon some adequate grounds for making up the one +kingdom from the other. What the consideration of form, movement, +chemical composition, and microscopic structure could not effect for +us in this way, it might be supposed the investigation of the diet of +animals and plants would render clear. Our hopes of distinguishing the +one group from the other by reference to the food on which animals and +plants subsist are, however, dashed to the ground; and the diet +question leaves us, therefore, when it has been discussed, in the same +quandary as before. + +Nevertheless, it is an interesting story, this of the nutrition of +animals and plants. A large amount of scientific information is to be +gleaned from such a study, which may very well be commenced by our +having regard to the matters on which a _green_ plant feeds. I +emphasize the word "green," because it so happens that when a plant +has no chlorophyl (as green color is named in the plant world) its +feeding is of diverse kind to that which a green plant exhibits. The +mushroom or other fungus may be taken as an illustration of a plant +which represents the non-green race, while every common plant, from a +bit of grass to an oak tree, exemplifies the green-bearing order of +the vegetable tribes. + +Suppose we were to invite a green plant to dinner, the _menu_ would +have to be very differently arranged from that which would satisfy a +human or other animal guest. The soup would be represented for the +plant's delectation by water, the fish by minerals, the joint by +carbonic acid gas, and the dessert by ammonia. On these four items a +green plant feeds, out of them it builds up its living frame. Note +that its diet is of inorganic or non-living matter. It derives its +sustenance from soil and air, yet out of these lifeless matters the +green plant elaborates and manufactures its living matter, or +protoplasm. It is a more wonderful organism than the animal, for while +the latter can only make new protoplasm when living matter is included +in its food supply, the green plant, by the exercise of its vital +chemistry, can transform that which is not living into that which is +life-possessing. + +The green plant in other words, raises non-living into living matter, +while the animal can only transform living matters into its like. This +is why the plant is called a constructive organism, while the animal +is, contrariwise, named a destructive one. The result of the plant's +existence is to build up, that of the animal's life is to break down +its substance, as the result of its work, into non-living matter. The +animal's body is, in fact, breaking down into the very things on which +the green plant feeds. We ourselves are perpetually dissipating our +substance in our acts of life and work into the carbonic acid, water, +ammonia, and minerals on which plants feed. We "die daily" in as true +a sense as that in which the apostle used the term. And out of the +debris of the animal frame the green plant builds up leaf and flower, +stein and branch, and all the other tokens of its beauty and its life. + +If, then, an animal can only live upon living matter--that is to say +on the bodies of other animals or of plants--with water, minerals and +oxygen gas from the air thrown in to boot, we might be tempted to hold +that in such distinctive ways and works we had at last found a means +of separating animals from plants. Unfortunately, this view may be +legitimately disputed and rendered null and void, on two grounds. +First of all, the mushrooms and their friends and neighbors, all true +plants, do not feed as do the green tribes. And secondly, many of the +green plants themselves can be shown to have taken very kindly to an +animal mode of diet. + +A mushroom, thus, because it has no green color, lives upon water, +oxygen, minerals, and organic matter. You can only grow mushrooms +where there is plenty of animal matter in a state of decay, and as for +the oxygen, they habitually inhale that gas as if they were animals. +Non-green plants thus want a most characteristic action of their green +neighbors. For the latter in daylight take in the carbonic acid gas, +which is composed of carbon and oxygen. Under the combined influence +of the green color and the light, they split up the gas into its two +elements, retaining the carbon for food and allowing the oxygen to +escape to the atmosphere. Alas! however, in the dark our green plant +becomes essentially like an animal as regards its gas food, for then +it is an absorber of oxygen, while it gives off carbonic acid. If to +take in carbonic acid and to give out oxygen be held to be a feature +characteristic of a plant, it is one, as has been well said, which +disappears with the daylight in green plants, and which is not +witnessed at all in plants that have no green color. + +So far, we have seen that not even the food of plants and animals can +separate the one kingdom of life from the other. The mushroom bars the +way and the green plant's curious behavior by night and by day +respectively, in the matter of its gas food, once more assimilates +animal life and plant life in a remarkable manner. Still more +interesting is the fact, already noticed, that even among the green +tribes there are to be found many and various lapses from the stated +rules of their feeding. Thus what are we to say of the parasitic +mistletoe, which, while it has grown leaves of its own, and can, +therefore, obtain so much carbon food from the air on its own account, +nevertheless drinks up the sap of the oak or apple which forms its +host, and thus illustrates the spectacle of a green plant feeding like +an animal, on living matter? Or, what may we think of such plants as +the sundew, the Venus' fly trap, the pitcher plants, the side saddle +plants, the butterworts and bladderworts, and others of their kind, +which not only capture insects, often by ingenious and complex lures, +but also digest the animal food thus captured? A sundew thus spreads +out its lure in the shape of its leaf studded with sensitive +tentacles, each capped by a glistening drop of gummy secretion. +Entangled in this secretion, the fly is further fixed to the leaf by +the tentacles which bend over it and inclose it in their fold. Then is +poured out upon the insect's body a digestive acid fluid, and the +substance of the dissolved and digested animal is duly absorbed by the +plant. So also the Venus' fly trap captures insects by means of its +leaf, which closes upon the prey when certain sensitive hairs have +given the signal that the animal has been trapped. Within the leaf the +insect is duly digested as before, and its substance applied to the +nutrition of the plant. Such plants, moreover, cannot flourish +perfectly unless duly supplied with their animal food. Such +illustrations of exceptions to the rule of green plant feeding simply +have the effect of abolishing the distinctions which the diet question +might be supposed to raise between animals and plants. We may return +to the sundews and other insect catchers; meanwhile, I have said +enough to show that to the question, "Can we separate animals from +plants?" a very decided negative reply must be given. Life everywhere +exhibits too many points of contact to admit of any boundary line +being drawn between the two great groups which make up the sum total +of organic existence.--_Illustrated London News._ + + * * * * * + + + + +THE RECOVERY OF SILVER AND GOLD FROM PLATING AND GILDING SOLUTIONS. + + +In view of the rapid development and extension of the methods of +electro-plating with silver and gold, and of the large amount of spent +liquors containing silver or gold thus produced, it has long been +desirable to find methods by which these metals can be recovered from +the spent liquors. The processes hitherto adopted generally +necessitate the tedious and unpleasant evaporation of the cyanide +liquors, or else involve a series of chemical operations which are +somewhat difficult to carry out, so that actually the used-up baths +are sold to some firm which undertakes this recovery as a particular +branch of its business. + +A process invented by Stockmuir and Fleischmann, and worked out by +them in the chemical laboratory of the Bavarian Industrial Museum, is, +however, exceedingly simple, and is employed in many establishments. + +In order to remove silver from a potassium cyanide silver solution, it +is only necessary to allow a clean piece of plate zinc to remain in +the liquid for two days; even better results are obtained by the use +of iron conjointly with the zinc. In the first case, the silver often +adheres firmly to the zinc, while in the second it always separates +out as a powder. It is then only necessary to wash the precipitated +powder, which usually contains copper (since spent silver solutions +always contain copper), dry it, and then dissolve it in hot +concentrated sulphuric acid, water being added, and the dissolved +silver precipitated by strips of copper. The silver thus obtained is +perfectly pure. If the amount of copper present is only small, it can +usually be removed by fusing the precipitated powder with a little +niter and borax. + +In this way a spent silver bath was found to contain per liter + + 1st experiment 1.5706 grms. + 2d " 1.5694 " + ------ + Mean 1.5700 " + +The presence of silver could not be qualitatively ascertained in the +residual liquor. + +Although sheet zinc, or zinc and iron sheets, serve so well for the +precipitation of silver, they cannot be employed for the recovery of +gold. The latter separates out in such a case very incompletely and as +a firmly adhering lustrous film in the zinc. On the other hand, finely +divided zinc, the so-called zinc dust, is an excellent substance to +employ for precipitating gold quantitatively and in the form of powder +from spent cyanide liquors. When zinc dust is added to a spent gold +bath and the liquid periodically stirred or shaken, all the gold is +precipitated in two or three days. The amount of zinc to be added +naturally depends on the quantity of gold present. Freshly prepared +gold baths for gilding in the cold contain on the average 3.5 grms. +gold per liter, while those used for the hot process contain 10.75 +grms. To precipitate all the gold in the original bath, 1.74 grms. or +0.37-0.5 grms. zinc dust would be necessary, and, of course, a much +smaller quantity would be sufficient for the spent liquors. Since the +precipitation takes place more rapidly when an excess of zinc dust is +present, it is generally advisable to add ¼ or at the most ½ kilo, of +zinc dust to every 100 liters of solution. + +The precipitated gold, which contains zinc dust and usually silver and +copper, is washed, freed from zinc by hydrochloric acid, and then from +silver and copper by nitric acid and thus obtained pure. + +A spent bath treated in this way gave the following amounts of gold +per liter: + + 1st experiment 0.2626 + 2d " 0.2634 + Mean 0.2630 grms. + +The presence of gold in the residual cyanide solution could not be +qualitatively detected. The potassium cyanide of the solutions +obtained by this process should be converted into ferrocyanide by +heating with ferrous sulphate and milk of lime, since this substance +is not poisonous and can therefore be got rid of without danger. 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