formed of two pieces of timber hinged at the edge below. They are kept asunder above by a plate of wood B. At different distances on the plate B are slips (shown apart, at C), which serve to keep open the wedge at different angles. From a roller at either side of the wedge passes a cord to a pulley, placed level with the rollers, and fastened as may be convenient; for instance, to the window and door trimmings of a room. The [frame ff and base D with blocks bb are only to keep the wedge and rollers in position until the weights W W are hung upon the cords, and P placed upon the "back of the wedge." A convenient sort of weights for this apparatus are jars (see figure); they are in themselves heavy and can be well proportioned by water, which will also serve to increase their general weight. Thus prepared, a series of experiments may be exhibited with the apparatus. 66 place on its back a P sufficient for equilibrium. regarding this 'machine." Let an inclined When W W are allowed to act, the strain on the plane be wound round a cylinder until the cords (which will perhaps even render a musical height and point" meet as above. There note if made to vibrate) gives a good idea of the is thus formed one turn of the screw. From intense resistance of a body to the splitting action the top of the "height" the same plane starts of a wedge. This "impression" of force, be- again, and winding, as before, produces the comes startling by removing quickly the cap of second turn of the screw. In the same way the the wedge; the two plates, A A, slap together 3rd, 4th, . . . . nth turn; in a word, the whole with a violence which gives a most appreciable screw is constructed. It may then be described proof of the very great force that the wedge had as a perpendicular series of inclined planes having the same "height and base" wound consecutively round a cylinder. resisted. these are all wedges, single or double, they work WEDGE APP. II.-THE ARCH.-This very im- Two "essentials" of the inclined plane change their name in the screw (Fig. 85). The height is called the "pitch," a a, the distance between two turns; the length is called the "thread" or "worm" of the screw. The "base" has no special name in the screw, but is represented by the circumference of the cylinder on which the thread or worm is rolled. The action of the screw is that of the inclined plane. The force which it has to resist is frequently not that of gravitation; but the force, whatever it be, is always applied, as gravitation is applied on the inclined plane. The action of the resisting force is usually exerted by what is called a nut.. This nut is a hollow inclined plane of the same pitch as the thread of the screw. As the nut covers usually two or more turns of the screw, the real action of the machine is concealed, and will be removed by a return to the inclined plane may be not clearly understood. All confusion (Fig. 86). Instead of the weight being placed upon a small space, a b, suppose it (the same FIC. 86 the whole length of the plane. Now such is the weight) spread (see dotted line from A to B) over duty of the nut, it distributes the force over the whole surface of the plane. (To be continued.) THE MITRAILLEUR. THIS weapon, of which we have heard so much lately, is but an improvement of an 83, are called the roussoirs, a a... The wedges which compose the arch A, Fig. the chief is the centre one, A, commonly called Of these the key-stone. side from what are called the abutments, B B. The voussoirs start at either Now, supposing the materials capable of resisting as long as the weight of the voussoirs, a a. and whatever weight may be added abovepasses to the abutments, the arch is safe. But if the resultant of the forces pass outside the line of the abutments, the resultant may take effectEXPERIMENT I.-Fix the wedge at its smallest the arch may be burst in, out, or up-the voussoirs angle, make P (at a guess) somewhat heavier (the wedges) yielding as in No. II. of the wedge exthan shall be required for equilibrium, when periments. Fortunately this giving way is to a the heavy weights W W are allowed to act. Let certain extent prevented by the surfaces of buildTHI W W act. By "feeling "the wedge (raise it a ing materials. These surfaces within limits of old idea. In the Hotel de Cluny, at Paris, there little) it will appear whether P is, or not, too certain angles will not slide one over the other. is a carbine with several barrels constructed heavy. If it be too heavy remove some of the These "sliding angles" being well known enter upon the principle of the revolver, which is said water (in P) until P shows no tendency to push into the calculation of the stability of a given to have belonged to Charles IX. or Henry III. of the wedge down. One block b may now be re- arch, which, consequently, may still be safe France, but certainly dating from the period of moved (the second is left for fear of any accidental though the forces (the pressures) act slightly the Massacre of St. Bartholomew. In a work on slip down of the wedge), equilibrium is com- along a line not passing to the abutment. In 'Weapons of War," by M. Auguste Demmin, pletely established, and the great power of the thus considering the arch as made up of wedges, translated by Mr. C. C. Black, Assistant-Keeper wedge may be somewhat estimated by the it is clear that l' is not the wedge as a machine, of the South Kensington Museum, appears the difference of the weight P, and the sum of W W. but the reverse that is required. In the arch the following account of what is now called the This experiment will be more striking if the base wedges are to be in equilibrium such that motion Mitrailleur, or Mitrailleuse :with supporting frame be removed (drawn down be impossible. from under the rollers); there is then nothing to meet the eye but the forces in equilibrated action. EXPERIMENT II.-Restore block b, stop the action of W W (by any convenient method-a second cord, a block, &c., to each), remove P, and open the wedge to next pair of slips) wider. Replace P, hold it on the "back by additional weight or otherwise; allow W W to act. The weight of P in the first experiment is no longer able to command W W; the wedge is pushed up if the holding force on P be diminished still more; if it be suddenly removed, the wedge may be suddenly shot out from between the rollers. Should this exciting conclusion be intended, there must be some provision for saving the wedge, &c. from injury. The experiment may be continued by pouring water into P until the now broader wedge is in equilibrium. Remove P, open the wedge still wider, replace P, &c.; again the same action of W W as above. Thus is shown experimentally the great practical principle of the wedge, "that the smaller the angle the better the action." EXPERIMENT III.-Make W W as heavy as the cords can safely bear, open the wedge wide, and thing in the essentials of an inclined plane It is very difficult, in fact almost impossible, to piece was named differently in each large city. L'orgue classify exactly, according to the names then in use, all the different species of cannon, for very often the same a serpentins, which was a machine composed of a great number of guns of small bore, loaded either from the muzzle or at the breech, had each separate chamber encased as far as the muzzle in wood or metal; the chambers were fired in succession or all at once. In Germany they were called Todtenorgel (death-organ). Weigel, writing in 1698, says that in the arsenal at Nuremberg there were organs with thirty-three pipes to them, and that death might be said to play dance music on them. One of the earliest of these machines is in the museum at Sigmaringen. It was made at the beginning of the fifteenth century. It is loaded from the muzzle, and is composed of small upright iron cannons rudely mounted on what looks like the trunk of a tree, and moves on two round discs of wood for wheels. Another of these machines, termed Orgue de danse Macabre, copied in 1505 by Nicolaus Glockenthon from one of the arsenals of the Emperor Maximilian, is composed of forty squareshaped tubes firmly joined together and mounted on a stand with large wheels somewhat similar to the carriage of a field-piece. A third one, of the seventeenth century, consisting of forty-two barrels, mounted so as to form a triangular block, and to fire six successive volleys, is now in the museum at Soleure. From Etudes sur l'Artillerie, by Napoleon III., published in 1846, it will be seen that there were some of these machines which could fire 140 shots at once. Similar weapons to these are, we believe, to be seen in the Tower, but they all lack the distinguishing characteristic of the Mitrailleur rapidity of fire, or rather of continuous fire. The Montigny (or "Christophi-Montigny ") mitrailleur, now under trial in this country, is a Belgian invention, and although similar to the French weapon in construction, is supposed to be superior to it in mechanical detail. pearance it resembles an ordinary field-gun with In ap a greatly enlarged breech-piece; but on looking at the muzzle, instead of a single bore, we find 37 holes, each about in. in calibre. These holes appear as if bored into the solid gun, but in reality, 37 hexagonal steel barrels are fitted accurately together, and soldered into a thin external wrought-iron tube. This tube has a movable breech action, worked by means of a lever, and containing a spiral spring and striker for each barrel. The cartridges are placed in a movable steel breech-plate, having as many holes as there are barrels. This plate is introduced into its place at the breech, which is then closed and secured by the lever. By means of a handle resembling that of a barrel-organ, the 37 cartridges can be fired independently, and as slowly as may be desired; or by a rapid turn of the wrist, the whole number can be fired almost simultaneously, the time occupied being one second. The empty plate can be replaced by one ready filled in the space of five seconds; and a continuous fire, at the rate of ten discharges per minute maintained, being equal to 370 shots; and as each bullet weighs 600 grains, this gives something over 311b. of lead per minute. The fire can be concentrated on one spot (the piece having but little recoil), or by means of a horizontal or mowing movement the flight of the bullets can be altered between each discharge, or during the discharge itself, so as to spread it over a wide front, somewhat in the manner of a fan. The mitrailleur is effective up to 1,000 yards. Its weight is only 400lb.; it is rifled on the Metford system. The bullet which is hardened, weighs 600 grains, and the charge of powder is 115 grains. The exact calibre is 534in., and the cartridge may be either Boxer or metallic, as preferred. The mean absolute deviation at a range of 500 yards is 31in.; mean angle of elevation 1' 24". At 800 yards, the mean absolute deviation is 51in., and the elevation, 2° 5", whilst at 1,000 yards, it is 2 35". The Gatling gun, in the possession of the Prussians, is a heavier weapon, and partakes more of the character of artillery. It contains ten barrels of a calibre sufficient to throw lin. shot or shell to consider but the expression of changes possible to the e person's brain. It seems important to fully comprehend that phenomena attendant upon changes occuring 2 ganisms, as results of their experience of the lo acting upon them, are dependent upon their str ture, as regards matter and arrangement. Alth this principle appears to be well understood in ve sciences, it still seems necessary to dwell up here, for it has been so long and universala sumed that living organisms are endowed with special supernatural power, vital force, of communicated to them at their creation and p ing from them at death, that the notion has le firmly fixed, and, although held without po difficult to displace without the strongest l knowledge of the laws which govern or ap requiring for this purpose a more or less ea changes of matter and force throughout t verse, and the phenomena attendant there well is the fact established, in chemistry, the finite chemical compound always acts in t manner under precisely similar condit when two substances are found that act d under such conditions, and are found by an be composed of the same elements in the portions, they are considered as having a ment of elements peculiar to each; and, try, this is, perhaps, the only satisfactory tion possible. By reason of such different ment, they are essentially different compon stove is a different structure from a stea although made of the same material in the proportions. sulphur and phosphorus in small but definite proportions. As they exist in the various plants and animals, and in the different organic tissues, they are variously modified, although always definite compounds, and essentially the same in the same tissue of a given kind of organism. The sap of plants, the blood of animals, and, in fact, each fluid and tissue of plants and animals, is a definite chemical compound, formed by combination of such definite proximate principles as we have been considering. As the proximate principles are peculiar to each organism, or, as is sometimes the case, to each tissue, the tissues formed by their combination are also peculiar, as, in many cases, proven by chemical analysis. The fluids and tissues, chemical compounds peculiar to each kind of orof which all organisins are composed, being definite gauism, all organisms may be considered definite compounds, the composition being peculiar to each kind of organism. While this is in general terms true, it is not 'the whole truth; for, while these simple compounds, which consist of small proportions of only one or two elements are strongly marked, stable compounds, not easily destroyed, and capable of little if any modification, the more complex compounds, consisting of many atoms of several elements, are, fication in various ways. on the contrary, more unstable, and capable of modiThe more complex the compound, the more easily modified, and the greater number of modifications possible, and consequently the more numerous the varieties, until, in those organisms which are extremely complex, no two individuals are precisely alike. Throughout This reference to mechanical structures serv their existence, they are also continually undergo- remind us that in mechanics, also, it is well c ing changes caused by surrounding forces acting stood that function depends upon structure. upon their easily-modifiable tissues, and are not, assumption of a vital force peenliar to each mar therefore, precisely the same at any two periods of would be considered ridiculous by all who know their existence. This is true of such an organized machines are constructed; and yet if a person co whole, considered as a compound, and also of the be supposed to exist having no knowledge of several tissues of which it is composed, they being chines except their external appearanee and visit: definite compounds. In fact, the organism is movements, that person might conclude that sone changed by changing its tissues and fluids, and supernatural power impelled them, and that, whe they by changing their proximate principles. Those motion ceased, the soul had left them dead: the tissues which are most complex are most easily Chinaman's watch that" died last night" illustrates modified, as well as capable of greater variability, this in a manner. Biologists, physiologists, and all as is seen by referring to the different tissues in the who most thoroughly understand the structure and human body. The bones, teeth, and hair, being function of organisms, mast, it seems to me, beable distances. In the matter of loading and composed of a few small-atomed elements, are com-lieve that in them, as in all chemical compounds, paratively simple compounds, and are the most and as in mechanical structures, function depends firing it is somewhat similar to the Montigny stable, resisting the surrounding forces long after upon structure. Believing with Herbert Spener. and the French mitrailleur. Whether these the softer tissues have disappeared; they are also that "the doctrine that all organistas are built weapons will have the extraordinary effect ex-less susceptible of modification during life, as their of cells, or that cells are the elements out of which pected of them remains to be seen. In certain rate of change is not so rapid; they, moreover, vary every tissue is developed, is but approximately tr positions, and under certain conditions, they will little in different bodies. The brain, on the other There are living forms of which cellular structur undoubtedly play a very important part in the hand, is an extremely complex compound, formed cannot be asserted; and in living forms that are fo needless war which is about to devastate a large by the union of complex, fatty, albuminous, and the most part cellular, there are nevertheless or portion of Europe. other compounds. After death, it is one of the first tain portions which are not produced by to tissues to decay, and during life it is so easily modi- metamorphosis of cells." "(Principles of Biolog fied as to be not precisely the same in any two p. 10.) individuals, or even in the same individual at We may, however, accept the evidence of t two slightly separate periods of time. (The same is eminent physiologist, M. Virchow, on the st seen-although not as plainly-in another way of function as dependent upon structure, when races of men are compared: those of the lower altogether indorsing the cellular hypothesis 1 races have hair nearly alike, of one and the same he so strongly advocates. "Life," says M. V colour, whereas, the higher-organized men of civi- "is the activity of the cell; its characters lized races have hair of various shades. The brain, those of the cell. A cell is a real body, cœ and consequently the shape of the heads, of highly-determined chemical substances, and coTM ORGANIC LIFE. BY H. B. BAKER, M.D., of Wenona, Mich., U.S. THE BEGINNING OF LIFE. ITS LOWEST FORM, AND E come now to still more complex compounds, We come to ousting of many atous of euch of civilized ques of men, varies more than among the according to determined laws. the three elements, carbon, hydrogen, and oxygen; the composition of one of them, stearin, being stated as C114 H110 O3 + CHO. Fats, as they exist in or ganisms, are, moreover, compound compounds compounded, for, in the higher organisms, they are made up of various proportions of oleine, stearin, and margarin, each of which is composed of a base and a fatty acid, as for instance, stearin consists of glycerine and stearic acid. There seems no limit, except the mathematical one, to the various proportions in which these fats may be combined. In some fats and oils, glycerine is replaced by other bases, and there are numerous volatile and other acids which are peculiar to fats from certain organisms. From these facts we should expect just what we find, that the mumber and variety of different kinds of fats and oils are beyond computation. They are peculiar in each particular form of life in which they exist, although more than one may exist in the same organism, for they are sometimes peculiar to a particular tissue. That the oils from the various plants are peculiar to each will be appreciated when it is remembered that many of them are sold under the name of the plant from which they are derived; as rose, peppermint, olive, and castor oils. In animals, we know that the same is true; fat from the pig is lard; from the sheep and ox we have tallow, differing slightly in composition. Most human fat contains a large proportion of margarin. As an example of different kinds of fat in different tissues of the same organism, we may mention the oil and spermaceti which are obtained from different portions of the whale. The albuminous proximate principles have been considered stili more complex compounds. They have other elements in addition to the three before mentioned, and consist of carbon, hydrogen, oxygen, and nitrogen; some of them also contain uncivilized). Beginning with the lower chemical compoundsalum and ammonia may be modified by substitution of one element for another, the former by addition and subtraction of water, &c. Sugar may be moditied by addition or subtraction of the elements of water. The minute living things, seen under the microscope, which appear to be nothing more nor less than particles of albumen, may be really so, and still be (of several kinds, as albumen is known to be) variously modified, according to the organism from which it is derived. The complexity and consequent modifiability of organisms are very greatly increased as soon as any form of fat appears as a constituent. Oleine, being one of its simple forms, is itself composed of two lower compounds-glycerine and oleic acid-both quite complex. We find, under the microscope, great numbers of different organisms, which appear to be simply albuminous and oily matter variously modified. The addition of earthy matters, such as carbonate and phosphate of lime, furnishes other elements of variability, but not to such an extent as the addition of the larger-atomed elements, carbon, hydrogen, oxygen, and nitrogen. While there is probably only one kind of pure water, there are several kinds of starch, many kinds of sugar, immense numbers of albuminous compounds, and an innumerable variety of fats. The power of variability, being so rapidly multiplied by combination of compounds already variable, we can easily see that the variety of ways in which such variable compounds may be combined to form higher ones, will result in such number and variety as will be practically infinite. The human brain being one of these most complex compounds, it is easily modified by very slight experiences of force; and the variety of changes which may be effected in it, through action and reaction with its various surroundings, is beyond the power of one imagination to conceive the imagination of one person being, as is believed, Its activi with the substance which forms it and All the peculiarity is confined to this, nam Again, referring to chemistry, we know that th freezing and boiling points of liquids, though dif ing with liquids that differ in constitution, are ti for each, and are always the same under precise similar conditions. Points at which various s stances fuse and ignite are fixed and peculiar each; in fact, there are fixed limits within whi any given chemical change can only occur, Fin the whole science of chemistry is based upon ti one great truth, that function depends upon stea ture, that any given substance behaves in precise * Revue des Cours Scientifiques. April 7, 1966 the same manner under precisely similar conditions; otherwise no analysis would be possible, for in what does chemical analysis consist? The methods of quantitative analysis consist in bringing the subStance under examination into contact with other bodies of known properties, and observing the phenomena which ensue.' These "other bodies of known properties" are called reagents, and "the ensuing phenomena are termed reactions." "By means of reagents, the chemist puts questions to the substance under examination, inquiring whether it contains this or that group of chemically similar elements, or only this or that member of such group. If the question be put correctly, i. e., if all the conditions under which the reaction expected can be produced by the reagent employed be carefully observed, the answer is decisive as to the presence or absence of the element or group of elements sought."-(Handbook of Quantitative Chemical Analysis, by Prof. R. C. Kedzie.) action of these forces, used in constructing the more replacement be made by substance not capable of, highly-organized herbivorous animals; finally, by in turn, giving place to the proper matter under the further action of the several forces, matter and the natural conditions, then the succession of force, from these previous structures, are still fur- changes is interrupted, and if this abnormal subther built up into the complex and highly-organized stitution be complete and permanent, death must human being. If any of the conditions to the exist- result; for, if an essential element combine with ence of these organisms be withdrawn, they return foreign matter, it is equivalent to its removal, and toward their constituent elements. All the changes this involves the destruction of the organisin. Thus, have been from stable to comparatively unstable if, in passing through the lungs, the blood gives off compounds, which, as we have elsewhere seen carbonic acid, and, instead of meeting with oxygen, (when considering the "Laws of Chemical Change "), combines with some other element, as, for instance, require force for their continuance. When, through chlorine, not capable of going through the changes the action of some starting force, these organisms in the tissues essential to the continuance of life, break up, either totally or in part, into lower com- death must result. Many poisons, such as hydropounds, they undergo a change from unstable to eyanic and other acids, alkalies, etc., may cause stable, and, in accordance with the general law death by combining with and refusing to release (elsewhere stated), force is liberated. Throughout essential elements of the organism. It seems quite all Nature the evolution of force is the result of probable that the acids of arsenic may act by thus change from conditions which required force for combining with the iron of the blood. This theory their production to conditions requiring less force. is supported by some facts, among which are, first, Since all organisms are definite chemical com- All organic motions result from changes, greater or the colour of the blood is in great degree due to pounds, we see that the several phenomena which less in amount, from unstable to comparatively sta- iron; the use of arsenic in sufficient quantities, for collectively make up the life of an individual or-ble compounds, requiring force to start them, but a length of time, causes a certain paleness of the ganism, and which are similar to the phenomena liberating force while they continue. These changes complexion; and, secondly, hydrated-peroxide of exhibited by all other organisms of its particular are, first, rearrangement of the constituent atoms iron has been found to be the most effectual antikind, and different from those of any other kind, or molecules; and, secondly, combination with other dote, and is supposed to act by combining with the may be considered as the reactions which occur in atoms or molecules. The rearrangement may be arsenic to form a compound insoluble in the fliuds consequence of its being brought "into contact slight, such as that which in chemistry is termed of the alimentary canal. May not a similar comwith its surroundings. In all organisms of a kind isomeric, giving out a small amount of force, and pound of arsenic and iron be formed in the blood, these reactions are similar, because all such organ- requiring but little to regain its former vital condi- and, if not insoluble, incapable of giving up the iron isms are similar chemical compounds. tion, or it may be a more or less complete breaking to go through its proper changes in the body? up into new and lower compounds constituting a mode of decomposition. Probably by far the greater amount of motion result from changes by combination with other elements not necessarily forming a part of the organism, and mainly through union with oxygen. This mode of change may vary from the slight substitution of one atom or molecule for another, to be in turn replaced by one precisely similar to the first, through the continued action of the organizing forces, up to sufficient decomposition to permanently destroy the organism. In considering the liberation of force, we will follow the same order as when tracing the successively higher forms which are produced through its organizing action on matter; noticing first the crystal, then the plant, and finally the various modes of animal force. Beginning with one element, the atoms definitely arranged by force, we know that when carbon, crystallized in the diamond, is heated to redness, and placed in an atmosphere of oxygen, it unites with it, and in burning gives out some of the force used in its formation, as moelcular motion, heat and light. amount of heat-force is required to start the change, A certain and certain surrounding conditions are essential to its continuance, but under those conditions, the diamond is an unstable form of matter, and is decomposed to assume a form requiring less force for its maintenance. The decomposition of certain chemical compounds yields electrical and other modes of motion. Throughout all Nature we find that function depends upon structure, although, in living organisms, it has been assumed to be otherwise. I have endeavoured to point out that all organisms have definite chemical composition, which is, in great degree, essentially similar in all organisins of a kind and different in different kinds. In order to correspond with what is recognized in mechanics and other sciences as natural law, and in order to harmonize with the fundamental truth upon which the science of chemistry is based, the individuals constituting each species of organism having similar definite chemical composition should exhibit similar phenomena when exposed to the several reagents which make up their surroundings, and that they do this is a fact too familiar to require illustration. The individuals of different species or kinds of organisms, having a different composition and structure, should exhibit different phenomena when exposed to the same reagents or surroundings; and this is a wellrecognized fact. Those species most nearly similar in chemical structure should most nearly resemble each other in the phenomena attendant upon their experience, and that they do so is also well known. Those tissues in different organisms which in structure closely resemble each other should have a corresponding resemblance of function. This fact is strikingly apparent, as we see when we remember that the brain and nervous system have a similar, though not precisely like, composition in all animals, and perform similar functions. The muscles of different animals are similar in structure as they are also in function. A survey of the evidence leads us to the conclusion that the phenomena, reactions, or functions which collectively make up the life of an organisin must result from its definite composition. In other words, life consists of the phenomena exhibited by definite chemical compounds while experiencing conditions compatible with their existence. As the reactions of all chemical compounds and mechanical structures are peculiar to each composition or structure, so the phenomena of any organism are peculiar to that organism, and result from the action and reaction between it and its surroundings. As before stated, "a definite chemical compound reduced to its lowest terms should consist of two equal atoms arranged with the simplest definite relation to each other." It is a well-known fact that the more or less combination with oxygen, is nearly complete, and change depends upon the nature of the change, The amount of force given out during any and cannot be determined from the result of any other change not precisely the same in character. In illustration: natural forces organize carbon and other elements into wood, and by its partial destruction charcoal remains; they form the compound nitrate of potassa; additional force is enployed by man in pulverizing and mixing charcoal, sulphur, and nitrate of potassa, to form the highly-unstable substance, gunpowder: the application to this of a proper force starts a chemical change, and more stable compounds are formed, liberating the amount of force stored up in it, less the amount necessary to form and maintain the lower compounds. changes of carbon, sulphur, and potassa, or even No experiments with the with those occurring in compounds of those elements combined in any other way, enable us to determine the amount of force liberated during the combustion of gunpowder. It seems improchange occurring in the brain can be properly bable that the amount of force given out by any estimated from any experiment with ordinary carbonaceous or nitrogenous compounds. precisely similar change in a compound chemically It can only be experimentally determined by a the same, where the lower compounds formed shall be the same in character as those formed in the brain. The same may be said of a change occurring in the muscular substance or in any tissue or fluid of the body. Inasmuch as the different tissues and fluids have not chemically the same composition, the changes occurring in them may not be similar; they probably are, to that if the amount of force liberated by a certain a certain extent at least, peculiar to each; so change in the blood be known, the fact will not the nature of the changes is known to be the occurring in any other part of the body, unless serve to prove the amount liberated by a change same. As force is indestructible, the amount longer acting to maintain it, will, in some form, used in building up any compound, when no appear. "The force liberated by the fall of a body is equivalent to the force required to raise the body to the height from which it fell." It is intended at a future time to continue the sub- the same might be accomplished by the force occurring in an organism must equal the amount ject by considering the remaining prominent charac-stored up in the crystal. In the sensitive plant teristics of living beings and also mutilation of or- (mimosa) we have an interesting example of motion, ganisms. ORGANIC MOTION; THE ACCTION OF SOME POISONS, which may be frequently repeated during its life, as the attendant decomposition, or change, is not, as in the foregoing examples, complete. In the complete decomposition of animal organCertain motions, not entirely dependent upon ex-isms, force is liberated; but the complex structure ternal force, are manifested in living organisins, and are called Organic Motions. There are several kinds, visible and invisible, such as muscular, causing motion of a part, or of the individual; nervous, inducing muscular and other motions, osmotic and circulatory motions of the fluids; and molecular motion-heat, light, and electricity, Force is the name given to the cause or producer of motion, and each kind of motion is understood as a mode in which force acts. In order to better understand the source of the force used in organic motions, we will begin with some of the most familiar kinds of matter and force, and rapidly trace them through some of their changes up to the higher-organized forms. of animal bodies renders possible, during life, various simultaneous changes of different characters, occurring in differently-constituted tissues, which have different conditions of stability, and in different portions of the same tissues more freely exposed to force. The great variety of changes which thus occur liberate force in a great variety of modes, causing heat, electricity, nervous, muscular, and other motions. In the higher organisms, such changes normally continue only until a certain portion of the particular tissue or form of matter has undergone this change, for the complete withdrawal of one essential element from an organism is equivalent to its decomposition. During the continuance of such changes force is manifested, Through the action of the several modes of force and, in time, by the continued supply of proper -heat, light, attraction, &c.- elementary matter is matter and several forces, the organism is again rearranged into molecules and crystals; from these stored to about its original condition, when it is the saine forces, through the directing influence of again possible for force to be liberated upon exgerms, build up the more complex vegetable organ-perience of the proper starting-force. By a certain isms; the matter and force stored up in the vegetable set of changes, by replacement or substitution, these and lower forms of matter are, through the continued phenomena of force may at intervals recur. If the The amount of force liberated by any change the unstable compound undergoing the change, less required to build up, from the chemical elements, the amount required to form and maintain the lower and more stable compounds formed during the change. From the Journal of Psychological Medicine. VOLCANOES. Na lecture upon this subject, delivered in connection with the Sunday Lecture Society, Mr. David Forbes, F.R.S., &c., said that, although he imagined that but very few of his hearers ever witnessed a volcano in eruption, all must have read accounts of such phenomena. As a geologist, he might be pardoned regretting that we do not possess even a single example of an active volcano in our happy isles. If the question were asked, · What is a volcano?" the simplest reply would be, "A hole in the ground deep enough to reach such portions of the interior of the earth as are in a inolten condition." The eruption of Etna in 1865, which the speaker witnessed, did not proceed from the summit or main crater, but broke out on the side of the mountain, about 5,416 feet above the level of the sea. Along the fissure formed by the convulsion, no less than seven distinct cones rose up at intervals, building themselves up very rapidly from the enormous quantities of scorice which were THE THE RUDDICK STEAM ENGINE. HE accompanying illustrations of this engine are taken from the American Artisan. The piston heads, A A, are rigidly connected by four rods, the two upper ones showing at F F. These rods insure an equal motion of the two piston heads in the same direction and at the same time. The piston being thus extended by these rods, admits of the interposition of the connecting rod B, from a wrist-pin in one piston head to the crank shaft, C, which runs transversely through the cylinder, carrying on one end the belt or fly-wheel, and operating on the other the valve stem, D, which is moved by the short arm, E, attached to a crank pin on an adjustable collar fitting on the crank shaft. The valves and steam chests are represented at H H. The advantages claimed for this engine are:1st. Extreme simplicity, beyond any other make of engine. A reference to the annexed plan and explanation readily confirms this. This quality of simplicity insures 2nd. Fewer parts, and each part contributing directly as a medium of power, and consisting only of the cylinder, piston, connecting rods, crank, valves, and valve stem. 3rd. Greater saving in repairs, on account of the fewer parts, and equal durability as compared with the best engines. 4th. Greater economy in space and weight than any other engine, and consequent economy in transportation. A 15-horse power engine, weighing less than 1,000lb., is included within a space of 42in., longest measurement, all set up with belt wheel, &c., ready to run. 5th. Can be run in any position, and at any reasonable speed. The cylinder must preserve the same right line, and the engine requires no founda tion. 6th. Greater economy in use, not only from saving in repairs, but the few and simple parts in this engine do not require an experienced engineer to run and keep it in order. Any intelligent boy of fifteen could be taught to run and take all needful care of one in a day's instruction. and that although the Mohammedan doctors issued a The connection of war and water is perhaps not studied by military officers generally, except so far as relates to the transport of large bodies of troops across seas and rivers; whilst the conclusion drawn by most non-military persons would be that the discussion of war and water must relate exclusively to naval warfare. If we accept the doctrine of Mr. Le Maout, we shall learn what lamentable results such ignorance may lead to. As Mr. Le Maout is the author of a work entitled "The Cannonades of Sebastopol, or the Cannon and the Barometer," published in 1856, it appears that he has occupied himself for some time with the question; and he considers that his observations, made during the Russian war, and published at the time, establish in an unequivocal manner the condensing action of cannon upon cloud, and consequently their effect upon barometrical indications. This action was constantly observed in Brittany in from 100 to 120 7th. Its simplicity insures cheapness of con- minutes, although the distance from the seat of the struction, and consequent reduced cost to pur-war was more than 600 leagues as the crow flies. chasers, while at the same time its cheapness does During the formidable cannonades of the seige of not in the least particular affect its power and use- Sebastopolhe noticed that generally-n Brittany we fulness. On the contrary, its simplicity is a posi- presume whenever the firing commenced the tive mechanical gain, using, as it does, every neces- azure of the sky was overcast, and a fine rain or sary part, and discarding all that are not directly, mist fell, frequently followed by heavy showers and and in the shortest line, mediums of power. The then by wind. Afterwards, and as a consequence consumption of power in the engine itself is un- of these condensations, the barometrical column was avoidably less, and the amount transmitted to the put in motion, and rose at a speed and to a height distributing point in like degree greater than in the proportional to the extent of the cannonade. The case of any other engine. record of the barometrical indications represented pretty exactly the extent of the firing when the effect was not modified by some great physical phenomena, such as a volcanic eruption or a great fire. Then the rarefying force neutralized the condensing force, and the barometer remained stationary until one or the other conflicting forces ceased to operate. But still more marvellous, and what attests the extreme sensibility of the instrument, he observed, that after six memorable engagements, followed by armistices of two or three hours concluded for the burial of the dead, the barometer stopped, and remained stationary during the whole It can be made of any power, from one-half horse power or less, to any required size. WAR AND WATER. HAT inability to apply the principles of logic, or insufficient confidence in the soundness of those principles, not unfrequently causes conclusions to be drawn which scarcely follow from the premises has long been known; thus, we are told, that in the reign of Abdallah III. there was a great drought at Bagdad, time the burial was going on; then, just after tw or three hours, at the moment when the cannonading recommenced, the column again gave signs of movement upward, and by its speed made up for lost time. It was this remarkable property that enabled him to calculate the exact time that was required for the force applied in the Crimea to exert its influence in Brittany. In And it is not cannon alone that possesses this condensing action. Mr. Le Maout has found that the explosion of mines and powder-mills, and even the sound of bells, produce a similar effect. Even the simple striking of a village clock, and of those of churches and chapels, suffices, on the coast of Brittany, where they have almost constantly a humid atmosphere, to make the rain fall; but for this certain physical conditions are necessary. The wind must be blowing from the south-west and carrying rain-cloud, and the barometer must stand below 76 centimètres. In this state of things, when the temperature is not high, it is rarely that the striking of the hours does not show its condensing action upon the aqueous vapour, especially when the clouds are low, for the vibration of bells and of clocks striking only acts within a limited area. the month of May, 1856, the year of the great inundations, he carefully observed the exact time of the fall of the rain, and found that, out of 133 times that it rained in the month, the fall occurred 76 times at the striking of the hours, 42 times at the half-hour, 8 times at the three-quarters, and 7 times at the quarter. He considers that it is the intensity of the sound, as well as the repetition, that has the most powerful effect upon the condensation of the vapour of water; and he explains that such observations cannot be made in Paris and other large towns, where so many noises are produced from fortuitous or accidental causes between the times the striking of the clocks. Speaking generally, he maintains that all noises produced by physical or artificial causes result in the condensation of aqueous vapours. Thus the beating of the drum, and the sound of military music where brass instruments predominate, produce identical effects, and it is the same with heavily-laden wagons passing over paved streets, and with trains of loaded trucks on railways. The vapour of water being formed of myriads of vesicles of the smallest diameter, similar as to their fragility to soap-bubbles, it is not surprising that, by the powerful percussion of the aerial mass, they should break, and resolve themselves into rain. When we are enveloped in this vapour by a sky charged with rainclouds, we are in a most impressionable medium, which for its fragility, may be compared to a palace of glass. If, under these circumstances, we fire a cannon, all will be smashed to atoms, and necessarily fall about our ears. If, however, there be nothing above us but the azure of heaven, we may fire cannon and ring as long as we like, yet nothing will fall. "It is this," says Mr. Le Maout, "that the adversaries of my doctrine of condensation will not understand; they wish, as proof of the truth of it, that rain shall fall under all circumstances." of Now, were this the sole objection to Mr. Le Maout's hypothesis, he would certainly have grounds of complaint, for it must be acknowledged that there are many experiments which can only be |