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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.

place on its back a P sufficient for equilibrium. When W W are allowed to act, the strain on the cords (which will perhaps even render a musical note if made to vibrate) gives a good idea of the intense resistance of a body to the splitting action "of force, beof a wedge. This "impression comes startling by removing quickly the cap of the wedge; the two plates, A A, slap together with a violence which gives a most appreciable proof of the very great force that the wedge had

resisted.

WEDGE APP. I.-CUTTING INSTRUMENTS.-As these are all wedges, single or double, they work better or worse as the practical principle is more or less observed. Therefore the finer the edge, i.e., the longer the edge, the better. The limits of reducing the cutting angle must be ruled by the work to be done. The harder, tougher, &c., the material, the wider must be the limiting angle, for the wedge of the cutting instrument having to overcome a greater opposition requires more of its own particles in the line of action to bear against the increased resistance.

WEDGE APP. II.-THE ARCH.-This very important element of architecture, would require, to do it justice, knowledge beyond the present reach of the student; a good notion then of its principle of action must suffice. (In general terms, therefore, it may be said to consist of a number of wedges so laid together, that the force from their own weight, and from any weight that may be superadded, is transferred to, and opposed by, an infinite resistance, or what in the possible circumstances is equivalent to an infinitive resistance. By infinitive resistance is to be understood a resistance capable of permanently arresting the action of the force under consideration. gard of this force such a resistance is practically infinite.

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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 wedges which compose the arch A, Fig. Of these The [frame ff and base D with blocks bb 83, are called the roussoirs, a a... are only to keep the wedge and rollers in position the chief is the centre one, A, commonly called until the weights W W are hung upon the cords, the key-stone. The voussoirs start at either and P placed upon the back of the wedge." A side from what are called the abutments, B B. convenient sort of weights for this apparatus are Now, supposing the materials capable of resisting jars (see figure); they are in themselves heavy as long as the weight of the voussoirs, a a. and can be well proportioned by water, which will and whatever weight may be added abovealso serve to increase their general weight. Thus passes to the abutments, the arch is safe. prepared, a series of experiments may be exhi- the resultant of the forces pass outside the line bited with the apparatus. of the abutments, the resultant may take effectthe arch may be burst in, out, or up-the voussoirs (the wedges) yielding as in No. II. of the wedge experiments. Fortunately this giving way is to a certain extent prevented by the surfaces of building materials. These surfaces within limits of certain angles will not slide one over the other. These "sliding angles" being well known enter into the calculation of the stability of a given arch, which, consequently, may still be safe though the forces (the pressures) act slightly along a line not passing to the abutment. In thus considering the arch as made up of wedges, it is clear that l' is not the wedge as a machine, but the reverse that is required. In the arch the wedges are to be in equilibrium such that motion be impossible.

EXPERIMENT I.-Fix the wedge at its smallest angle, make P (at a guess) somewhat heavier than shall be required for equilibrium, when the heavy weights W W are allowed to act. Let W W act. By "feeling" the wedge (raise it a little) it will appear whether P is, or not, too heavy. If it be too heavy remove some of the water (in P) until P shows no tendency to push the wedge down. One block b may now be removed (the second is left for fear of any accidental slip down of the wedge), equilibrium is completely established, and the great power of the wedge may be somewhat estimated by the difference of the weight P, and the sum of W W. This experiment will be more striking if the base with supporting frame be removed (drawn down 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

* All rights reserved.

+ By a mistake of the engraver the diagram is not made sufficiently clear. The cords should pass to the roller farthest removed from it-that is, the cords from

P should act on the right-hand roller as you look at the roller.

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The application of this principle will show engraving, and the cor fom Pact on the left-hand what a screw is, or answer the first question

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is thus formed one turn of the screw.
"the same plane starts
the top of the "height
again, and winding, as before, produces the
In the same way the
second turn of the screw.
nth turn; in a word, the whole
3rd, 4th,
screw is constructed. It may then be described
as a perpendicular series of inclined planes having
the same "height and base" wound consecutively
round a cylinder.

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
The "base" has no
"worm" of the screw.
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 action of the resisting
the inclined plane.
force is usually exerted by what is called a nut..
This nut is a hollow inclined plane of the same
As the nut
pitch as the thread of the screw.
covers usually two or more turns of the screw,
the real action of the machine is concealed, and
All confusion
may be not clearly understood.
will be removed by a return to the inclined plane
Instead of the weight being placed
(Fig. 86).
upon a small space, a b, suppose it (the same

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weight) spread (see dotted line from A to B) over the whole length of the plane. Now such is the duty of the nut, it distributes the force over the whole surface of the plane.

(To be continued.)

THE MITRAILLEUR.

Tmuch lately, is but an improvement of an HIS weapon, of which we have heard so old idea. In the Hotel de Cluny, at Paris, there is a carbine with several barrels constructed upon the principle of the revolver, which is said to have belonged to Charles IX. or Henry III. of France, but certainly dating from the period of the Massacre of St. Bartholomew. In a work on Weapons of War," by M. Auguste Demmin, translated by Mr. C. C. Black, Assistant-Keeper of the South Kensington Museum, appears the following account of what is now called the Mitrailleur, or Mitrailleuse :

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It is very difficult, in fact almost impossible, to classify exactly, according to the names then in use, all the different species of cannon, for very often the same piece was named differently in each large city. L'orgue 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

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sulphur and phosphorus in small but definite pro-
portions.

As they exist in the various plants and animals,
and in the different organic tissues, they are vari-
ously 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 combina-
tion 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,
of which all organisins are composed, being definite
chemical compounds peculiar to each kind of or-
ganism, all organisms may be considered definite com-
pounds, the composition being peculiar to each kind of
organism.

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 ap-
pear 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 re-
sembling 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 movementfication in various ways.
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 eleva-
tion 1' 24". At 500 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

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It seems important to fully comprehend that t phenomena attendant upon changes occuring 21 ganisms, as results of their experience of the te acting upon them, are dependent upon their st ture, as regards matter and arrangement. Althy this principle appears to be well understood in zi sciences, it still seems necessary to dwell up here, for it has been so long and universals sumed that living organisms are endowed withk special supernatural power, vital force, of communicated to them at their creation and p ing from them at death, that the notion has leks firmly fixed, and, although held without pot difficult to displace without the strongest F requiring for this purpose a more or less ecs knowledge of the laws which govern or ap changes of matter and force throughout t verse, and the phenomena attendant theret well is the fact established, in chemistry, the finite chemical compound always acts in the manner under precisely similar condition when two substances are found that act as

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 com- under such conditions, and are found by are be composed of the same elements in the pounds, not easily destroyed, and capable of little if any modification, the more complex compounds, portions, they are considered as having at.. consisting of many atoms of several elements, are, ment of elements peculiar to each; and, i on the contrary, more unstable, and capable of modi- try, this is, perhaps, the only satisfactory The more complex the tion possible. By reason of such different compound, the more easily modified, and the ment, they are essentially different compo greater number of modifications possible, and con- stove is a different structure from a steame sequently the more numerous the varieties, until, in although made of the same material in the those organisms which are extremely complex, no proportions. 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 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 peculiar to each mad 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 coll 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 visibl 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, becomposed of a few small-atomed elements, are com- lieve that in them, as in all chemical compounds, firing it is somewhat similar to the Montigny paratively simple compounds, and are the most and as in mechanical structures, function depends stable, resisting the surrounding forces long after upon structure. Believing with Herbert Spencer. and the French mitrailleur. Whether these the softer tissues have disappeared; they are also that the doctrine that all organisms are buil 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 wish 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 structure 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 t 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 two slightly separate periods of time. (The same is seen-although not as plainly-in another way when races of men are compared: those of the lower races have hair nearly alike, of one and the same colour, whereas, the higher-organized men of civi lized races have hair of various shades. The brain, and consequently the shape of the heads, of highly civilized races of men, varies more than among the uncivilized).

able distances. In the matter of loading and

ORGANIC LIFE.

BY H. B. BAKER, M.D., of Wenona, Mich., U.S. (Continued from page 464.)

WE

THE BEGINNING OF LIFE. ITS LOWEST FORM, AND
THE SIMPLEST ORGANISMS-(continued),
E come now to still more complex compounds,
the fats, consisting of many atoms of each of
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 com-
pounded, for, in the higher organismis, they are
inade 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 propor-
tions 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 or-
ganisms.

From these facts we should expect just what we find, that the number 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 obtained from different portions of the

are

whale.

The albuminous proximate principles have been considered still 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

Beginning with the lower chemical compoundsalum and ainmonia 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,

We may, however, accept the evidence of t eminent physiologist, M. Virchow, on the s of function as dependent upon structure, altogether indorsing the cellular hypothesis he so strongly advocates. "Life," says M. V "is the activity of the cell; its characteriz those of the cell. A cell is a real body, cœ ̈. determined chemical substances, and coaccording to determined laws. Its activi with the substance which forms it and -contains; its function varies, increases at → nishes, appears and disappears, with the the growth, and the diminution of the sule? But this matter does not differ in its elements* the inanimate matter of the inorganic king which, on the contrary, it constantly employster fect itself, and to which it returns after having complished its special duty. That which is to its own is the manner in which the matter is posed of, the peculiar grouping of the minutest ticles of matter, and yet this grouping is n peculiar as to be in opposition to the disposit and groupings which chemistry detects in inorg bodies. That which seems to us peculiar is kind of activity; the special functions of orga substance; and yet this activity and these functi do not differ from those which natural philosop studies in the inorganic world.

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All the peculiarity is confined to this, nam that in the smallest space are condensed the Le varied combinations of substances, that each cell the focus of the most intimate actions of the varied combinations, and that it thus prod effects which are met with nowhere else in Nat because nowhere else can we find a similar intine of action."

Again, referring to chemistry, we know that th freezing and boiling points of liquids, though ing with liquids that differ in constitution, are five for each, and are always the same under precise similar conditions. Points at which various st stances fuse and ignite are fixed and peculiar t each; in fact, there are fixed limits within which any given chemical change can only occur, Finally the whole science of chemistry is based upon tuis one great truth, that function depends upon store ture, that any given substance behaves in precisel

Revue des Cours Scientifiques. April 7, 1866.

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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 sub-
stance under examination into contact with other
bodies of known properties, and observing the phe-
nomena 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 care-
fully observed, the answer is decisive as to the pre-
sence or absence of the element or group of elements
songht." (Handbook of Quantitative Chemical
Analysis, by Prof. R. C. Kedzie.)

Since all organisms are definite chemical com-
pounds, we see that the several phenomena which
collectively make up the life of an individual or
ganism, and which are similar to the phenomena
exhibited by all other organisms of its particular
kind, and different from those of any other kind,
may be considered as the reactions which occur in
consequence of its being brought "into contact
with its surroundings. In all organisms of a kind
these reactions are similar, because all such organ-
ismus are similar chemical compounds.

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 sub-
ther 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 organism. 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 hydro-
pounds, they undergo a change from unstable to cyanic 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,
All organic motions result from changes, greater or the colour of the blood is in great degree due to
less in amount, from unstable to comparatively sta- iron; the use of arsenic in sufficient quantities, for
ble compounds, requiring force to start them, but a length of time, causes a certain paleness of the
liberating force while they continue. These changes complexion; and, secondly, hydrated-peroxide of
are, first, rearrangement of the constituent atoms iron has been found to be the most effectual anti-
or molecules; and, secondly, combination with other dote, and is supposed to act by combining with the
atoms or molecules. The rearrangement may be arsenic to form a compound insoluble in the flinds
slight, such as that which in chemistry is termed of the alimentary canal. May not a similar com-
isomeric, giving out a small amount of force, and pound of arsenic and iron be formed in the blood,
requiring but little to regain its former vital condi- and, if not insoluble, incapable of giving up the iron
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 combina-
tion 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 simi-
lar 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 mat-
ter; noticing first the crystal, then the plant, and
finally the various modes of animal force. Begin-
ning 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 burn-
ing gives out some of the force used in its formation,
as moelcular motion, heat and light. A certain
amount of heat-force is required to start the change,
and certain surrounding conditions are essential to
its continuance, but under those conditions, the
diamond is an unstable form of matter, and is de-
composed 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 organisms 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 intended at a future time to continue the subject by considering the remaining prominent characteristics of living beings and also mutilation of organisms.

ORGANIC MOTION;

THE

ACCTION OF SOME POISONS,
AND THE ESTIMATION OF ORGANIC FORCE.

Certain motions, not entirely dependent upon ex.
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 un-
derstand 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.

It is a well-known fact that the more or less complete decomposition of ordinary vegetable forms is attended by a liberation of force, generally as heat. When the steam-engine is operated by the use of wood as fuel, organic force is used for the movement of machinery; tree-power is made to aid, or is substituted for horse-power, as both of these are used to save the higher form of power exerted by man.

The amount of force given out during any change depends upon the nature of the change, 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 em ployed 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. No experiments with the changes of carbon, sulphur, and potassa, or even 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 improbable that the amount of force given out by any change occurring in the brain can be properly estimated from any experiment with ordinary carbonaceous or nitrogenous compounds.

It can only be experimentally determined by a precisely similar change in a compound chemically the same, where the lower compounds formed shall be the same in character as those forined 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 a certain extent at least, peculiar to each; so that if the amount of force liberated by a certain change in the blood be known, the fact will not serve to prove the amount liberated by a change occurring in any other part of the body, unless the nature of the changes is known to be the same. As force is indestructible, the amount used in building up any compound, when no longer acting to maintain it, will, in some form, 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."

In this case the decomposition of the wood, by combination with oxygen, is nearly complete, and the liberated molecular motion is communicated to the water to form steam; but its continuance, as molecular motion, is resisted by the solid though moveable portion of the engine, and a certain portion is thereby converted into motion of a mass. Locomotion is thus rendered possible through the use of only the organic force of plant life. If the diamond were sufficiently plenty to be used as fuel, the same might be accomplished by the force stored up in the crystal. In the sensitive plant (mimosa) we have an interesting example of motion, which may be frequently repeated during its life, as the attendant decomposition, or change, is not, as in the foregoing examples, complete.

The amount of force liberated by any change occurring in an organism must equal the amount required to build up, from the chemical elements, the unstable compound undergoing the change, less the amount required to form and inaintain the lower and more stable compounds formed during the change. From the Journal of Psychological Medicine.

VOLCANOES.

upon this subject, delivered in con

In the complete decomposition of animal organisins, force is liberated; but the complex structure of animal bodies renders possible, during life, various simultaneous changes of different characters, occurring in differently-constituted tissues, IN a lecture th the Sunday Lecture Society, Mr. which have different conditions of stability, and in different portions of the saine 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 organisin 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 same 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

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 pos
sess even a single example of an active volcano in
If the question were asked,
our happy isles.
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

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thrown up at their vents. Uniting in action, they, in a short time, formed a range of hills several hundred feet in height, and entirely changed the character of the scenery of that part of the

island. The formation of a new, or the re-opening

MECHANICAL MOVEMENTS. (Continued from page 464.)

269. motion from different temperatures in French invention for obtaining rotary of an old, volcanic vent is usually accompanied by a two bodies of water. Two cisterns contain water: terrific explosion. In 1812 the outburst of the vol- that in left at natural temperature and that in right cano of Saint Vincent was heard in South America, higher. In right is a water-wheel geared with some 700 miles distant. The enormous force deve- Archimedean screw in left. From spiral screw of loped by the rush of gases and vapours from the the latter a pipe extends over and passes to the fissure may be imagined, when it is known that in under side of wheel. Machine is started by turning the eruption of Mount Ararat in 1840, huge blocks screw in opposite direction to that for raising water, of rock, weighing as much as 25 tons, were thrown thus forcing down air, which ascends in tube, crosses out of the crater. Cotopaxi is said to have hurled and descends, and imparts motion to wheel; and its a 200-ton rock to a distance of nine miles: whilst volume increasing with change of temperature, it is the volcano of Antuco, in Chili, in 1828, discharged said, keeps the machine in motion. We are not stones to a distance of about 36 miles from its ori-informed how the difference of temperature is to be fice. The chemical composition of the gasiform ema- maintained. nations from volcanoes proves that they are in greater part incombustible, and therefore does not support the idea that the body of such a column of vapour and gases could be in flames-i.e., actually burning. On the outside of the column, however, inbluish colour, due to particles of sulphur taking numerable brilliant scintillations are seen, of a fire as they come into contact with the outer air, and patches of melted sulphur are splashed about, brightly burning as they fall down through the air on to the slope of the cone. The buried cities of Stabiæ, Herculaneum, and Pompeii, covered in parts to the depth of 100ft. by the ashes of Vesuvius, are ocular proofs of the vast quantities which can be discharged out of a volcano vent during an eruption. A French grologist has estimated that the volcano of Bourbon has, in the course of only two days, thrown out no less than 300,000 tons of ashes. In that greatest of mountain ranges, the Andes, commencing from the oldest period of their elevation, we find a series of eruptive rocks breaking through the sedimentary strata on their flanks, as follows:

1. The Auriferous granites-probably at the end
of the Devonian period;
2. The characteristic Porphyrites of the Oolitic

age;

3. The Auriferous Diorites, disturbing the Creta-
ceous formation; then,

4. The Miocene basalts; and, lastly,
5. The lavas from the present volcanic forms,
which occur at intervals along the whole
range, from Terra del Fuego in the south, all
through the Cordilleras of South and Central
America, up to the Rocky Mountains.

In answering the question as to what force has played the most prominent part in determining the external configuration of the earth, the unbiassed geologist, said the lecturer, must necessarily grant the first place to the internal volcanic or cataclysmic agencies, since, had it not been for their operations, our globe would still have remained a comparatively smooth sphere.

270. Steam hammer. Cylinder fixed above and
hammer attached at lower end of piston-rod. Steam
being alternately admitted below piston and allowed
to escape, rises and lets fall the hammer.
271. Hotchkiss's atmospheric hammer; derives
head, C, is attached to a piston fitted to a cylinder,
the force of its blow from compressed air. Hammer
B, which is connected by a rod, D, with a crank, A,
on the rotary driving-shaft. As the cylinder
ascends, air entering hole e is compressed below
piston and lifts hammer. As cylinder descends,
air entering hole e is compressed above and
is stored up to produce the blow by its instant
expansion after the crank and connecting-rod turn
bottom centre.

272. Grimshaw's compressed air hammer. The
head of this hammer is attached to a piston, A,
which works in a cylinder, B, into which air is ad
mitted-like steam to a steam engine-above and
below the piston by a slide-valve on top. The air
is received from a reservoir, C, in the framing,
supplied by an air-pump, D, driven by a crank on
the rotary driving shaft, E.

273. Air-pump of simple construction. Smaller tub inverted in larger one. The latter contains water to upper dotted line, and the pipe from shaft or space to be exhausted passes through it to a few inches above water, terminating with valve opening upward. Upper tub has short pipe and upwardly opening valve at top, and is suspended by ropes from levers. When upper tub descends, great part of air within is expelled through upper valve, so that, when afterwards raised, rarefaction within causes gas or air to ascend through the lower valve. This pump was successfully used for drawing off carbonic acid gas from a large and deep shaft.

274. Eolipile or Hero's steam toy, described by Hero, of Alexandria, 130 years B.C., and now regarded as the first steam engine, the rotary form of which it may be considered to represent. From the lower vessel, or boiler, rise two pipes conducting steam to globular vessel above, and forming pivots on which the said vessel is caused to revolve in the direction of arrows, by the escape of steam through

a number of bent arms. This works on the sam principle as Barker's inill, 438 in this table.

275. Bilge ejector (Brear's patent) for discharg ing water under various circumstances. Da ing bilge-water from vessels, or for raising and for chamber having attached a suction-pipe, B, and d charge-pipe, C, and having a steam-pipe entering

one side, with a nozzle directed toward the dischar

pipe. A jet of steam entering through A exp
air from D and C, produces a vacuum i
causes water to rise through B, and pasti
D and C, in a regular and constant stra
pressed air may be used as a substitute for s
276. Another apparatus operating a
principle as the foregoing. It is ter
siphon pump (Lansdell's patent). A is t
BB, are two suction-pipes, having a fa
nection with the discharge-pipe, C. The sam
pipe entering at the fork offers no obstacle to t
upward passage of the water, which moves p
in an unbroken current.

277. Steam trap for shutting in steam, b
viding for the escape of water from steam cois
the waste-pipe, having an outlet at B, and furnis
radiator (Hoard & Wiggin's patent). It consist
a box, connected at A with the end of the roof
with a hollow valve D, the bottom of which is c
posed of a flexible diaphragm. Valve is filled
liquid, and hermetically sealed, and its diapar
rests upon a bridge over the outlet-pipe. Th
sence of steam in the outer box so heats the w
in valve that the diaphragm expands and
valve up to the seat, a, a. Water of condens
accumulating reduces the temperature of
and as the liquid in valve contracts, diap
allows valve to descend and let water off.

278. Another steam trap (Ray's patent). a closes and opens by longitudinal expansi contraction of waste-pipe, A, which terminate portion of the pipe is firmly secured to a fixed the middle of an attached hollow sphere, C. port, B. Valve consists of a plunger which work in a stuffing-box in the sphere opposite the end a pipe, and it is pressed toward the end of the pipe a loaded elbow lever, D, as far as permitted by stop-screw, b, and stop c. When pipe is filled wi water, its length is so reduced that valve remar that valve closes it. Screw, b, serves to adjust th open; but when filled with steam, it is expanded

action of valve.

279. Gasometer. The open-bottomed vessel, is arranged in the tank, B, of water, and partly counterbalanced by weights, C C. Gas enters the gasometer by one and leaves it by the other of the two pipes inserted through the bottom of the tank As gas enters, vessel A rises, and rice versa. The pressure is regulated by adding to or reducing the weights, C, C. (To be continued.)

Benzine is said to render ordinary paper trans parent and suitable for tracing purposes.

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and that although the Mohammedan doctors issued a THE RUDDICK STEAM ENGINE. decree that the prayers of the faithful should be accompanying illustrations of this engine offered up for rain the drought continued. The piston heads, A A, are rigidly connected by four those of the true believers, but the supplications of rods, the two upper ones showing at F F. These both were ineffectual. As famine stared them in rods insure an equal motion of the two piston heads face, those dogs, the Christians, were at length enin the same direction and at the same time. The joined also to pray. It so happened that torrents piston being thus extended by these rods, admits of rain immediately followed. The whole conclave, of the interposition of the connecting rod B, from with the mufti at their head, were now as indignant a wrist-pin in one piston head to the crank shaft, at the cessation of the drought as they were before C, which runs transversely through the cylinder, alarmed at its continuance. Some explanation was carrying on one end the belt or fly-wheel, and necessary to the people, and a holy convocation was operating on the other the valve stem, D, which is held; the members of it came to the unanimous moved by the short arm, E, attached to a crank determination that the God of their prophet was pin on an adjustable collar fitting on the crank highly gratified by the prayers of the faithful, that shaft. The valves and steam chests are repre- they were as incense and sweet-smelling savour unto him, and that he refused their requests that he might prolong the pleasure of listening to their supplications; but that the prayers of those Christian infidels were an abomination to the Deity, and that he granted their petitions the sooner to get rid of their loathsome importunities. Some conclusions about as logical have just been published by Mr. Ch. Le Maout, pharmacist, of St. Brieuc, in consequence of the drought we have recently experienced.

THE accompanying the American Artisan. The Jews were then permitted to add their prayers to of movement upward, and by its speed made up for

sented 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 foundation.

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.

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 attente extreme sensibility of the instrument, to operate. But still more marvellous, and what

It can be made of any power, from one-half horse power or less, to any required size.

WAR AND WATER. Tiam in the of those HAT inability to apply the principles of logic, or 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,

he observed, that after six memorable engagements,
followed by armistices of two or three hours con-
cluded for the burial of the dead, the barometer
stopped, and remained stationary during the whole

time the burial was going on; then, just after two or three hours, at the moment when the cannonading recommenced, the column again gave signs 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.

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. In 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, ont 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 of 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 stances. truth of it, that rain shall fall under all circum

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

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