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as crystalline or amorphous. Crystals are those bodies which possess a symmetrical form, and are bounded by plane surfaces called faces. The line formed by the junction or intersection of two faces is called the edge, whilst the point formed by the junction of three or more faces is called the solid angle.

Axes are imaginary lines drawn through a crystal for the purpose of facilitating the description of its geometrical properties and all crystals which can be reduced to the same axes belong to the same system of crystallography.

There are six systems or distinct classes of crystals under which all known forms of crystals can be classed.

1st System. The octahedral or regular system, called also the cubical system when the cube is considered the typical form. If diagonals be drawn upon each face of the cube they will intersect in the centre of each face; lines now drawn so as to connect the centres of each opposite face will give the axes of the cube, of which there are three. The following minerals crystallize in the cubical or octahedral system :—

Zinc blende, alum, galena, silver, iron, salt, diamond, lead, gold, iridium, fluorspar, and iron pyrites. The crystals of this system exhibit only single refraction and expand equally in all direc

tions when heated.

2nd System. The typical form of this system is a right prism upon a square base, or an octahedron upon a square base, therefore it is called the right square prismatic system; it is often called the pyramidal system.

If lines are drawn joining each face of a right square prism from the centre they will represent the axes, of which two, as they are formed in a square, must be equal. The characteristic of the second system is three axes, two of which are equal. Crystals of this system exhibit the phenomena of double refraction, but they possess one negative axis, i.e., one which does not possess this peculiarity. The following minerals are found crystallized in this system:

Calomel, zircon, rutile, anatase, scheelite, and mellite. The crystals of the above system expand equally in at least two directions.

3rd System.-Rhombohedral or Hexagonal System. This system is characterized by possess ing three equal axes and one which is perpendicular to the other three. The axes may be found by forming the hexagonal prism and joining the centres of the opposite edges, these lines are the three equal axes; the other, and that which is perpendicular to the other three is found by joining the centres of the hexagonal faces.

These substances crystallize in the 3rd system: Calc-spar, quartz, bismuth, graphite, antimony, emerald, dolomite, ice, tourmaline, hæmatite, apatite, and amethyst. Double refraction and unequal expansion characterize this system.

4th System.-Prismatic or Rhombic.-This system, also called the right, rectangular or rhombic prismatic and orthotypic system, may contain crystals formed either from the prism or octahedron on a rhombic base. There are three axes peculiar to this system, no two of which are equal. The principal axis runs parallel to the long edges in the centre of the crystal; the secondary axes are lines joining the centres of the opposite long faces of the crystal; they are perpendicular to the principal axis.

Cryolite, nitre, sulphur, topaz, citric acid, sulphate of zinc, and bichromate of potash, crystallize in this system. They possess two axes of no double refraction and expand unequally in

three directions.

The following crystals belong to this system:Sulphate of copper, nitrate of bismuth, native boracic acid, axinite, and Labrador felspar.

A chemical compound generally crystallizes in one form belonging to one system, but some are found to crystallize in two forms, they are then termed dimorphous : as an instance, calcium carbonate is found as arragonite in the prismatic system, and as calc-spar in the rhombohedral system. Common salt generally crystallizes in cubes, but if deposited from a solution containing urea, the form is altered to that of an octahedron; and sal ammoniac, treated likewise, is said to form cubes instead of octahedrons, which it always furnishes in pure water.

Certain bodies when they take the crystalline form acquire a certain amount of water, which is necessary for the permanence of that form; when this water is expelled the crystal falls to powder, it is therefore called the water of crystallization.

A PRACTICAL TREATISE ON THE
HARMONIUM.*

BY HERMANN SMITH.

(Continued from page 458.)

THIRD DIVISION.-CHAPTER VI.

OF THE RESONANCE OF THE CHANNELS.

A musical note, far from being a repetition of the same simple sound, should be considered as the conjunction of subordinate sounds reiterated at proportional interappears to depend on the frequent recurrence of interior vals. The sweetness of this compound effect or tone unison.-PROF. LESLIE.

MUSICAL pipe is of true or perfect length A when it is capable of maintaining pulsations which synchronize with the vibrations of the exciting agent. The unison is integral and absolute. Nevertheless there may be many departures from this perfect condition which shall be agreeable to the ear; minute divergences which When crystals dissolve in water, the bulk of seem to waver on either side the balance, and variations to a range apparently beyond the this latter fluid is not increased if the crystals be governance of the same laws, remote from the same anhydrous; if such, however, is not the case, the system of tones. An organ would be a very tame increase is only by the amount of crystalliza- and spiritless affair if all its pipes were of perfect tion water they may contain. From a vast num-standard, and so likewise would the harmonium ber of experiments upon the subject it is probable be if we sought only to use one perfect scale of that hydrated crystals when in solution exist, channels; indeed we consider the principles of the not as a solution of the anhydrous salt, but as one of the hydrated crystals. A solution of sodium identical. Each instrument helps to explain the organ and the harmonium to be in all particulars sulphate saturated at 32.78° C. with the ten-atom other. The pulsations of a pipe have no dependhydrate, upon elevating the temperature, about one-sixth of the salt is deposited as anhydrous have a dynamical causation, of which sound is the ence whatever on sound; they exist prior to it, rhombic octahedrons. If a supersaturated (boiling) solution of sodium sulphate is made, and the the force is inherent in the constitution of air. accumulated effect. The power of transmitting vessel closed to exclude nuclei, it may remain This you should bear in mind, that air, being an for a long time before crystallization sets in, but elastic fluid, must of necessity vibrate or pulsate if nuclei are admitted in the shape of dust, or if whenever it is disturbed, even as water is under touched with anything surfaced with that which is foreign to its composition, it at once solidifies necessity, in like condition, of gravitating in a (see Nature, Aug. 4; Chemical News, xxii. If the surface of water is disturbed it is ruffled series of undulations until it attains equilibrium. page 560). But before we leave the subject of into waves; of these the eye takes cognizance by crystallization we will notice one point which has had such influence in the progress of chemical means of the intervals of lights and shadows. In analogous modes the results of the elastic force philosophy. affect the ear as sounds by reason of its power of which is active in the air when under disturbance, estimating the intervals of pulsations. We throw a stone into a lake, and it produces an annular wave; we see the circle expand and spread farther and farther until it subsides into quiet, all its impulse absorbed in the mass of water. It is the same when the air is stricken; it is agitated to ambient expanse. If those air-waves have cerundulations which spread and die away in the tain periodic times with quick repetition or definite rates of velocity, they become, to our perceptions, music. You should think of the condition of the

Substances are termed isomorphous when they crystallize in the same system, with an identical or but slightly different angular element, or when they are found intermixing with other substances without altering their form.

Mitscherlich has shown that bodies which possess an analogous constitution, exhibit also a similar crystalline form. Of this we have an instance of the manganese, chromium, aluminium, and iron alums. These alums possess the same crystalline form, and the sesqui-oxides of the above metals are termed isomorphous.

If we examine a crystal of magnesite (carbonate of magnesium) we find it belongs to the rhombohedral system; calamine or zinc carbonate belongs to the same system, and the angles vary but a few (15) minutes; therefore, by the law of Mitscherlich the oxide of magnesium is isomorphous with the oxide of zinc, and the two compounds possess an analogous constitution. Magnesium carbonate is Mg C Os, and zinc carbonate is Zn" C Og. Calcium in calc-spar, iron and manganese in the proto-salts, with nickel, cobalt, and copper, form with the above what is termed an isomorphous group. Acids also form isomorphous groups, as-1st, phosphoric acid, vanadic acid, and arsenic acid; 2nd, sulphuric, chromic, and manganic acids; while molybdic and tungstic acids are also isomorphous.

air quite apart from its musical effects. The condensations and rarefactions of air under impulse

constitute wave-motion.

Advance now a step further. Confine water in these will spread, will travel to the opposite end a trough; at one end agitate it, raising waves, and not cease there, but return with rebounded impulse,meeting and crossing over other oppositelyIn like manner if air is enadvancing waves. be returned and rebounded; but the waves of the vironed, enclosed in pipes, pulsations excited will condensations and rarefactions of air differ in this, that they have definite lengths and a celerity of motion of which water can give but a faint representation; for air is a free ocean surrounding us, and its ratio of elasticity is constant, whereas, in As an instance of the control of formule by the Analogy should not be forced too far: it has its comparison, water is elastic only on its surface. law of isomorphism, I may quote the recent re-limits, else it would be identity. searches of Professor Roscoe on the subject of the true atomic weight and constitution of the salts of vanadium. Berzelius assigned the formula V O, to the acid oxide; but Rammelsberg, a few years afterwards, observed that vanadinite ((Pb Cl2) + (PbO)2 + (Pb3 (V O4'2) was isomorphous with apatite ((Ca Cl Fl) + Caз (V O4)2), and with mimetite ((Pb Cla) + (Pbg (V O4)2), and it was then supposed that anhydrous vanadic acid had an analogous composition to the arsenic and phosThe following crystals belong to this system:-phoric anhydrides, viz., V, Og. Nothing was done Carbonate of soda, malachite, sulphate of iron, in the matter till Professor Roscoe took it up sulphate of cobalt, gypsum, felspar, Glauber's and thoroughly investigated it. The result of his salt, mica, and realgar. experiments was, that the vanadium trioxide of 6th System. Doubly Oblique or Anorthic Berzelius turned out to be a pentoxide, and the System. This system may be called the crystallic lower oxides exactly agreed with those of phoslumber-room: it is the system to which all crystals phorus. From the above experiments, which we are referred when they cannot be classed in any might say proceeded from Mitscherlich's law of of the preceding systems. Most of the forms of isomorphism, vanadium has been placed in its this system are characterized by their want of proper place among the metals, and its true symmetry: they possess three axes, all of which atomic weight established. intersect each other obliquely, no two therefore are inclined to each other at right angles.

5th System. The Oblique.-The typical form of this system is an oblique prism or an oblique pyramid upon a rhombic base. The behaviour of the crystals of this system under the influence of light and heat is similar to the preceding system. The principal axis runs in the centre of the prism, parallel to the oblique long edges, joining the two rectangular faces. The secondary axes join the centres of the long faces. In this system two axes are oblique, and the third perpendicular to both.

(To be continued.)

The perfect pipe of which we have spoken This class of would be the flue-pipe of an organ. pipes is always regarded by builders and philothe class of pipes called reed-pipes. As briefly sophers as being of a nature quite distinct from setting forth the doctrine, we note the following passage by Dr. Bushnan:-"In the flute, flageotions of the air are the source of musical sounds." let, and diapason organ-pipe the molecular undula

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And again, Dr. Brewer, in his work on Sound, speaking of reed instruments and reed pipes, flute and organ pipes). In the former the column says:- They differ essentially from those (viz., of air is only the auxiliary of the sounding body, in the latter it is the sounding body itself." believe to be erroneous. Our views do not coincide with these, which we We may not stay now note of the divarication as essential to the full to refute them, but can only ask you to take understanding of the statements we have to place before you and the arguments to be founded upon

Te copyright of this treatise is reserved by the

author.

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combination of the two into one system, or com-
pound resonance. Resonance may be manifested
in two modes: when the generator and resonator
are allied, their activity being reciprocative and
supporting, as in organ pipes, reed channels, and
musical instruments generally; and the second
mode, when the generator and resonator are isolated,
detached, and merely sympathetic in response, as
is the case with musical vases, hollow sounding-
boards, and the like. In whatever mode manifested
the physical action is the same, giving back the
wave-re-undative.

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them. No column or body of air is itself capable of sounding or of creating sound; it is always an auxiliary-a resonator, and nothing more. We hold the organ pipe and the harmonium channel to be both resonators. The difference is one of degree only, not of kind, and through all the varieties of pipes and channels we trace but one determining element, the relations of proportion. Thus the full-length eight-feet organ pipe is In general reference we may active in giving simple or integral resonance, the diminutive channel is active in giving multiple or suitable for flute stop; scale N lesser resonance. And what is resonance? If we scale O, for diapason stop; the am ask, with a child's persistency, what is resonance? The question remains, why resonance increases usual 8ft. stops included in f Scale P, for the fife stop why does resonance increase the power of any the power of tones? The re-undulated impulse, ments. tone? text-books and teachers sagely tell us it provided it is timed in concurrence with the tone; scale Q, for bourdon or doal means sounding again," or they tantalize with stroke of the generator, produces an augmentation Yet it must not be forgotten that merely formal explanations, which fail to reach of sound by reaction upon the agent, thereby in- pronounce definitely what quality the root of the inquiry. The best elucidation we creasing the amplitude of its vibration (intensity scale of channel will yield, we ha know of is to be found in Brande's "Dictionary of tone depending upon amplitude), and by re- the character of reeds, the sizes of ser of Science and Art." Resonance. In music a ceiving that strengthened energy upon a larger influence of pallets, and other de very indefinite term used in regard to the pro-area, and again propagating the impulse of an fore, be not too curious about precas duction or reverberation of sound." Admirably increased surface upon the external mass of absolute measurements, for should true, for the idea called up by the use of the term quiescent air. Resonance is to the generating maker's plans you will not of a sure resonance is generally as vague as this explana- sound an auxiliary in actual force; the arrow sults equal to his, unless you coul tion. Let us hope to obtain a little light at all flies faster with the wind. It conspires to aid the methods throughout up to the final tr events on the physical fact we want to express. original impetus, just as on the stage the spring-work. Your teacher may be lavish in Evidently the word is wrong; looking to its board aids the vaulter to increase the amplitude his special knowledge, and in giving the philological derivation it is seen at once to be of his leap, timed as the swing of the rope to the experience and study, yet there is a s inadequate, for we want to express the condition hand of the trapèze performer; musical vases are is incommunicable, and even figures canno which produces the musical result. The term is as springboards to the wave-tones that leap upon the minuteness which only munids d naturalized in science and cannot be displaced. their aerial surfaces. The organ pipe and the channel could adequately supply. Each It is, however, necessary for the development of harmonium channel differ only in degree, the one has his own particular set of sedes, to w our argument that we should define clearly what superior in extent of surface, the other inferior clings with partiality, and hence his instr we mean by " resonance." Let us coin a word in the front it can present to act upon the ex- bear features by which they are regura. for the occasion. When we say a pipe or channel ternal air. With your fingers you can agitate comparison with instruments of other miExcellence is of is resonant we would affirm a physical fact, that the air inferiorly, but take a fan in your hand, who use different scales. it is re-undative, that it returns the wave. and you communicate your impulse by the pre- degrees. To work out new scales a man needst sentment of a superior extent of surface with an be patient in observation and sagacions in infer enormous increase of power. Thus it is with the ence, sensitive to perceive quality in sands, and organ pipe; its larger orifice and more capacious eager to analyze the combistians concurring to mouth are the endowment of a giant, as com- produce the ultimate effes Liking at the pared with the diminutive scale and little aper- variations of channel, each and to respond to tures of the harmonium channel. The resonating 8ft. tone, there seems to be little appearance of power of the organ must, therefore, always tran- law or system; all looks asal and any, scend the capabilities of the harmonium. In a yet experience, the surest teacher, leads to a former chapter we illustrated the shapes of the very different conclusions. The de channels; we have now to set forth the scales apertures, which will be given in the next chat, or dimensions of the channels. Experiment tells exercise a most important influence, and res 2 us that when channel of about 18in. in length is principles deeply involved in the physiol allied to a reed of 16ft. tone we obtain the best the voice, although practically disregard quality of sound that reed is capable of afford manufacturers who disdain study. It is so ing. Now we cannot well use such a basis easier to rely upon custom, tradition, and rain d for the scales of the harmonium, or we should thumb. Our anxiety has been to interest ya occupy almost as much space as with the principles which govern the quality of organ, and have to adopt a similar system in Our next most necessary consideration rela building. No doubt a smoother bass would be the vowel qualities of reed tones, and the gained and better balance of tone, for at present of apertures thereon; the subject, origina the tenor and bass are shorn of their just pro- vestigated by Kratzenstein, and afterwas o portions, in order to economize space, and hence Prof. Willis, of Cambridge, yields to none the roughness or reediness preponderates, drown- for the student of the harmonium. ing the treble, unless great skill is exercised to restrain it within due bounds. The structure of the harmonium is compatible only with a system of reduced scales, and we can but select the best and be content with the compromise. Scale M, 8ft. tone. Length of Channel.

We will halt here and bring up the line of argument with which we started to rejoin at this point. The exciting agent at the mouth of a pipe has a periodic time of movement wherewith the column or body of air, by reason of the perfect accord of its wave-length, responds in faultless synchronism; the two movements meet together in time, or absolute unison. Imagine now that this double-natured pipe affords a parallel to the nature of two notes of a musical scale. Thus, two notes from two distinct musical sources may be sounded, and being of the same pitch, they sound the unison. We spoke of minute divergences, yes, the tuner well knows that they bear very considerable passage below or beyond absolute unison before they become discordant: yet mark this, the minutest change cannot be effected without producing appreciable difference in the quality of the combined tones. If instead of the unison we combine the octave, the wave of which is as two to one, we perceive a new result. In some kinds of organ pipes we obtain the parallel of this, either by diminished length or by forcing the wave-lengths to break up into lesser waves when we elicit harmonic re

We

lation or multiple resonance; hence also channels
of length, capacity, and proportion, accordant
with the multiple pipe, return the wave with
similar synchronism, even as a fifth, or third, or
fourth synchronizes with the fundamental note of
a chord. Strike the notes of a chord in succession
and you can recognize them again as regards the
quality of the tones as well as in their pitch.
Strike the same notes as a combined chord and
we feel that the tones have coalesced into some-
thing very different in the effect or display of
quality; the blended or compound tone is a new
product. A change in characteristics, as of
substances when brought anew into chemical
union. It may be for better or for worse.
often experience this in harmoniums; one that will
render a melody pleasantly will become intolerable |
as soon as the notes are thrown into combination
for harmony, and on the other hand an instrument
of real artistic worth will so blend in its harmonies
with infinite variety in effects of quality, piquant
flavours, glimpses of tonal colour so alluring, that|
the ear is never satiated with its charms, but
finds new beauty, new delights, day after day.
The same peculiarities are observable in organ
pipes and channels; according to the relation of
proportions in the associated generator and
resonator, so is the result affecting the ear: some
pipes of simple resonance are soft and agreeable,
others tame and dull; some pipes of complex
resonance and full of harmonics, are harsh and
jangled and almost unbearable, others are rich in
lovely qualities. What a compound of harmonics
in the tone of the French horn, yet what tone
more captivating to the musical ear!

We recognize three states of resonance: the integral resonance, or simple undulation of the whole -the diminished or multiple resonance-and the

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Scale O, 8ft. tone.

Scale P, 4ft. tone.

ELEMENTARY SCIENCE."

BY THE REV. E. KERNAN, CLONGOWES Cr (Continued from page 533.)

OW

APPLICATION X.

INCLINED PLANE.

Now studying the action of a comme

water, observing its defects, and these by the aid of the "consequences, will find himself face to face with the described in the first point.

It is clear that a screw placed i work a nut for itself, as a common

does in a piece of timber. The defects es mon screw working in water are four in Depth of Channel. To each defect let its remedy be appli remedies are to be found amongst the sequences." Taking at once an example, s a screw of which the "elements" are ma thus: "pitch" in., "breadth" of thread DEFECT 1.-YIELDING OF THE WATER.-. liquid state being so movable a form of mali the resistance is far from being equal to that the solid state. Hence the screw with elemen

Depth of Channel. as above would produce little or no motion. small quantity of water which touches the thre of the screw would yield to the force concentra thus in a small space.

CORRECTION I.-The "thread" of the screw

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pread out, from being, to (say) 5ft. in breadth.
the force now divided over a large surface being
auch diminished at the parts which make up that
urface, the water in contact with these parts is
ble to resist, the screw acts, the body joined to
he screw moves.
DEFECT II.-SMALL ADVANCE.-The height of
he inclined plane-the pitch of the screw-being so
nall (in.) the body only moves in. at each
The velocity therefore should be some-
aing incredible for any useful effect.
CORRECTION II.-The "pitch" of the screw is
ncreased, say from in. to 16ft. At each turn the
ody will advance 16ft. In Fig. 99 is represented

urn.

FIG.99

one turn of a screw of great pitch.

B

DEFECT III.-WASTE OF SPACE.-With the extended "pitch" there are large spaces-from A to B and under the two end-portions, C, C, of the shaft, Fig. 99-in which there is no work done. The work then is not so much divided as might be, and consequently the action on the poorly= resisting water is greater than need be.

CORRECTION III.-An Archimedean screw of 1, = 2, ... n threads is substituted for the screw with only one thread. The spaces A, B, C, C, of Fig. 99 are filled up by a second spiral, or "thread," in Fig. 100. Two being enough for the most complete

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I explanation, it were better not to render the diagram confused by more spirals. The work being thus much more divided, the water at the different parts is much better able to resist, as the whole amount of resistance (suppose to be the same as before) is now divided over a much larger area. Theoretically, therefore, it ought to be possible to make a screw so that the water should offer complete resistance, and consequently the ship should advance at each turn to the full pitch of the screw. Experience, however, showed that there was still an unthought-of defect.

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DEFECT IV.-MOTION OF THE WATER.-Practi

the consequence of the injury to the screw was now; the old "breaks" which formerly someincrease of speed. This fortunate accident led to what disfigured its evenness are to a great extent a series of experiments as to the real useful removed, and all its time-honoured beauties length. Piece by piece the screw was shortened, stand out in greater prominence. Whence, then, each cut giving improved speed, until about 1-6th the semi-contempt with which it is regarded, of a turn was reached. Here seemed to be the even by professors themselves? A greater relimit, and it is pretty generally admitted that proach to the musical world could scarcely exist about 1-6th is the efficient part of the screw. Let than the systematic manner in which this elegant the student now imagine a plane cutting off 1-6th and once fashionable instrument is ignored. Is of the screw, Fig. 100; the cut-off piece is the it that further experiment and alteration are propeller, such as was first shown in Fig. 94. As feared? That apprehension is groundless; both it is almost impossible to give a clear, correct, players and manufacturers have had enough of perspective view of the "cut" by a side view, that, and to spare, if vexation, anxiety, and loss are good preceptors; he would indeed be reckless who should adventure more time and money in

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Fig. 101 represents the double spiral turned for
an end view. The cutting plane A B is seen full
front, and exhibits the identity of the cut-off piece
with the propeller Fig. 94. The plane is supposed
transparent, and shows (through) one complete
convolution of the double spiral. The apparatus of
Fig. 100, being made with one piece movable,
removes every difficulty there may be of clearly
understanding the screw-action of the now so im-
portant propeller. The question "What is the
screw propeller?" may now be answered in a few
words. "It is a portion of an n-threaded screw."
This portion is every day receiving new forms, to
meet new minor defects, or to suit peculiar cir-
cumstances; and in some cases, although the
action still continues to be that of the inclined
plane, there is a deviation from the outline of
the strict screw, or "true screw," as it is called.
Much as this important subject has been studied,
there would seem still to be considerable difference
of opinion amongst practical engineers, even as
to its most important elements. The question is
much complicated by the form of the ship, the
currents running to and from the screw, &c. On
these points further detail would here be out of
place.

(To be continued.)

THE FLUTE AND ITS VICISSITUDES.
BY SABLE.
(Continued from page 459.)
THE REVOLUTION OF Вӧнм.

water in motion. The resisting power of the FEW reverses in the course of reconstruction as

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"used-up" an undertaking. It is certain that all professional players have now come to a sort of growling understanding as to the flute of their adoption, and that, and no other, will they recommend to their pupils.

It is both useless and foolish to cushion facts, even though they be disagreeable. The flute is a very difficult instrument to play thoroughly well; it has difficulties inherent to its nature; but so has every other instrument, and it is by conquering these that the student gradually emerges into the professor, and it is by deeming this conquest always imperfect that the professor arrives at distinction. Mr. Chapman (p. 469), writes as a master; his observations are the result of experience; the road to proficiency is rugged, albeit the personal aid of one like himself will render the rough places much smoother and pleasanter to pupils. A great deal is advanced about the difficulties of the extreme keys, but the real difficulty is more often to be found in the composer, and that in what are called the easy keys. It is worthy of remark that perhaps the greatest cause of the flute's neglect lies in the lukewarmness and want of energy and industry both of composers and professors. There were giants in "flutedom" in days past-why should there not be again? Whatever man has done, man can do, and greater means are now at his disposal.

The flute was what we hope to see it again. Its popularity as a source of recreation and enjoyment was unrivalled, but it was soon to be exiled from the drawing-room, driven from its position as a solo instrument, to become henceforth chiefly the occupant of the workshop and orchestra. As it had engaged admiration and regard, so also it engaged the eye of the critic; its defects were pointed out and enlarged upon, the necessity of a reformation was spoken of, and ere long it was commenced with a vengeance, it was stripped of its charm and simplicity, and what it gained in its resources and importance it lost in public favour. The defects of the eight-keyed flute lay chiefly in the cramp fingering for F natural. There was a difficulty in passing from octave to octave with freedom; there were some awkward cross and back fingerings; its tone was unequal; some notes were rich and full, others very dull and feeble. There is an obstacle, common to all instruments of its genus-as the oboe, clarionet, bassoon, &c.which the flute presents to the learner, i. e., passing from the last fundamental note to the first note of the octave immediately above, which often involves the simultaneous movement of all the fingers; this can never be completely removed, although it is now materially obviated. True it is that the access from C sharp to the D might be rendered perfectly easy, but it would simply be transferring the evil to the next note, and in that case the D (now a good note) would be harsh and thin in quality. The violin has its own peculiar difficulties, and the alteration of the distances in the "stop" in the different" 'positions" on the finger-board, commonly called the "shifts," may be included among the greatest of them; but if the violinist will put all his four fingers down on a string, and keeping them well down, do a rapid even shake with the little finger, he will realize something of the finger-gymnastics of the flute. This is bad enough; but let him replace all his fingers, and keeping the rest down try to execute a shake with the third finger, and he will experience the pleasant sensation inseparable from the anatomical arrangement of the tendons of this finger employed under such embarrassing circumstances. On referring to the drawing at page 459 it will be seen that two keys, a and b, are provided for the little finger of the left hand (G sharp and F natural); the use of the latter is sometimes very awkward and perplexing; to the right hand little finger are apportioned the three foot keys; the reader will thus see the labour imposed upon the weak digits. One other key only claims notice And the flute's voice was never sweeter than in this flute, the long C natural, manipulated

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cally it is found impossible to avoid setting the NEW instruments have passed through such
water is so small, that only a part of the screw the flute, and certain it is that no other has
finds a "nut " immovable for a moment.
Quickly this "nut" receives the rotatory motion
of the screw, which motion destroys all resistance
to the remainder of the screw. Besides this
negative effect, the moving water has a positive
retarding action upon the inefficient part of the
screw. Suppose that the space C B, Fig. 100,
represents the " working part (as it may be
called) of the screw; and that the ship be moving
in the direction of the arrows a, a. All the re-
sistance of the water is overcome in that space
C B, and besides the remainder C A having
nothing to work against as it advances into the
moving water, it is opposed by the backward
motion of this water, which produces a current in
the direction of the arrows b, b, which current
strikes the entire remainder of the screw. Even
were there no retarding current, the remainder of
the screw would be a drag upon the ship's pro-

suffered so severe a penalty; and if it is not
wholly consigned to oblivion, it is treated with a
coldness and neglect as unjust as it is undeserved.
The pianoforte and violin are not more popular
now than was the flute in the days of the
Nicholsons and the Ashes; a concert then with-
out a flute-solo would have been quite as un-
orthodox as the absence of a violin-solo at the
present time, and it always elicited an equally
hearty and well-merited encore. Our periodicals
teem with notices of musical doings; music was
never more cultivated and appreciated by the
public generally than at this period; new artists
and new music appear as regularly as the flowers,
and are welcomed with an unfailing interest: but
we look in vain amidst the names of those who
distinguish themselves as instrumentalists for a
flautist-soloists there are in goodly array, but the
voice of praise once raised for the "silver-toned"
flute is heard no longer. And why is this? Has
CORRECTION IV.-As every portion of the screw all love and admiration of the instrument died
acts independent of the rest," cut off the useful out? This little couplet, from the pen of a
part." The discovery of this correction was the popular writer, says
result of an accident, and seems to have preceded
the knowledge of the defect. In the early experi-
ments, the screw of one of the first ships was
partly broken. To the surprise of all concerned,

gress.

66

"Her voice

nay.”

So soft it was, and like the note

You ofttimes hear upon the flute."

with the first finger of the right hand. On looking at the finger-holes it will be seen that they are unequal in size and irregularly graduated, hence the unevenness of tone and flatness of the

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THE PROGRESSION OF LIFE.*

(Concluded from page 535.)

the same with the animal kingdom.

The

IT is the, the unity which it presents to us, in
volves the life and death, the genesis, the maturity,
the decline, not only of an infinite number of indi-
viduals, but also of a vast number of species and
families, which once having disappeared are never
reproduced. They too manifest in their evolution
the same law as each individual, the phases of
whose existence have conspired to form their dis-
tinctive character. And not only in so far as each
stage in their development, also, is inseparably
linked with the preceding one, but in this too, that
the whole course of that progression at any period
is portrayed in the changes which one individual,
that shall be taken as typical of the progress of
the species, undergoes in the course of its own
growth. Crustaceans, as we have said, present to
us, in their complex organizations, the highest type
at which the life of the earth had arrived at the close
of the Silurian and the beginning of the Devonian
epoch; but they were preceded by vast numbers of
individuals, whose abnormal forms were for a long
time a puzzle to geologists. But in the mature
form of many of these we now recognize the larval
like organization of those higher crustaceans which
succeeded them. Almost all the genera of Trilo-
bites," says Agassiz, "seem to be the prophetic
images, in a gigantic form, of the different types the
crustacea present in their embryonic state."

third octave, because those holes which serve for
vent holes in the production of the latter are
the purpose.
To
frequently too small for
finger A natural in the third octave every
aperture is closed with the exception of 1
and 6, these are very small holes, therefore,
the note is flat, thin, and requires great strength
of lip to render it well in tune and agreeable to the
ear. For E natural in this octave all the holes
are closed save 3 and 4; it is true that the
D sharp key is open, but this does not mate-
rially remedy the evil which results from the
smallness of the two holes actually engaged in
the delivery of the note. In the formation of the
fundamental E natural 6 is the hole uncovered,
with the addition of the D sharp key, and the re-
sult is a dull feeble note. Any pipe constructed
to emit a musical sound must contain within itself
a medium of resistance, and thus give an addi-
tional impulse to the vibrations of air as they pass
through it." Glancing again at the engraving, it
will be noticed that the body of the flute is coni-
cal, the diameter of the bore at the foot joint
being about one-third less than at the head (in
the flute from which the sketch is made it is only
one-fourth less, which perhaps accounts for the Again, the insect type is a more highly organized
fulness and beauty of its tone). But this conical one than the crustacean; and it is much later, in
bore offered rather more resistance than was need- the carboniferous epoch, that we obtain the fossil-
ful, preventing the flute from "
ized forms of true Insecta. But insects are divided
speaking freely,"
into two great classes-those which have an imper-
and causing that difficulty in "getting out" the fect, and those which have a perfect, metamor.
lowest notes with which amateurs are so pain-phosis; and through a series of strata, representing
fully familiar. To remedy this defect and equa- a vast interval of time, the forms and species of the
lize the position and size of the holes was the lower class are abundant, while those of the higher
study of Herr Böhm, a professor of Munich. In the are scarce to be found.
year 1728 a Captain Gordon, residing in Paris, laid Further, organisms that are recognized as fishes
the foundation of the system. It occurred to him become noticeable at the commencement of the
that if the handle of a key covering a distant hole Devonian epoch. But in what order do fishes, as a
was brought in a semicircle round the edge of a class, come into the world? Taking one of the
finger-hole above, two holes could be stopped by most highly organized fishes, such as it exists at
the action of one finger. Herr Böhm sent the first present, and noticing the changes it undergoes in
its development, we find that the growing embryo
practical model of this flute into England about has a vertebral column of cartilage before it deve-
1832, and it was protected by letters patent. The lops a perfectly osseous one; it has a one-lobed tail
flute now changed the form of its body from a cone before a two-lobed one; the position of the mouth is
to a cylinder. It was thought this would render the lower in the embryo than in the mature form. Look-
fundamental octave more full and free; shut keys ing at the species of fish now existing, we put those
were changed into open keys, the bore was equal with a cartilaginous skeleton, as the sturgeon, lower
in diameter throughout, the holes were enlarged than those with a bony one; the one-lobed tail is
and made equal in size to remedy the inequality considered a mark of lower organization than the
of tone and tune. The following is quoted from a
two-lobed one, and the inferior mouth is held to be
a characteristic of less perfect forms. But for thou-
treatise on the subject by the patentees :-"Equa-sands of years in the history of the world cartilagi-
lity of tone can only be obtained by means of nous fishes were the predominant, the only forms,
equal-sized holes." This is only another way of that peopled the seas. The characteristics of the
saying, take an organ pipe suitably graduated in heterocercal tail and the inferior mouth are here
length and diameter for the correct delivery of almost universal. It is not until the Chalk era that
its proper note, say tenor C, cut it in half, place the forms which give a specific character to the
it in the wind chest, and it will give you the fish-type of the present come into significance.
octave above. So it will, if double force of wind So that, in the words of Agassiz, "the embryo of a
be used; but the note will be harsh and disa- fish, during its development, the class of living
greeable, and out of tune, because the diameter fishes in its numerous families, and the fish-type
of the pipe is not proportional to its length. Never in its planetary history, go through analogous
phases." The embryo of a frog is, as we know,
was any fallacy so perversely held as that of equal to all intents and purposes, a fish, and in geological
sized holes. To obtain greater freedom in pass- order, Fishes, as we have seen, precede Batrachians.
ing from octave to octave the fingering One of the characteristics of the true reptile is that
was changed and all altered. The key arrange- the vertebræ are different from those of amphibia,
ments were entirely remodelled, and rings were which have more resemblance to the bi-concave
added to give the power of acting on holes now ones of the fish, and we have seen how huge Amphi-
placed beyond the reach of the proper fingers. In bians represented vertebrate life on the globe before
the next paper drawings will be given of the Böhm the appearance of true Reptiles. But man also, as
It was intended to give illustrations of the the head of the mammalia, gradually assumes the
specific characters which distinguish him from all
several forms which the instrument has assumed, other beings; passes through certain transitional
but when it is stated that during the years 1848 stages in which are sketched as it were, in rude out
and 1849 those eminent flute makers Messrs. line, the permanent forms of those types of animal
Rudall & Rose manufactured ten flutes for dif- organization which are held to be lower than his.
ferent schemers, all of which were during that That is to say that, commencing his existence in a
time discarded, it will be admitted that the space germ similar to that in which every form of exist
and time of the engraver are capable of better ence has its rise, he develops successively points
employment. The names of these instruments of resemblance to the fish, the reptile, the bird, and
are barely remembered: they were acoustical, the animal. Moreover, as we have said, the youth
scientifical, and mechanical, but they could not of the civilized man has much in common with the
rescue them from oblivion, and nothing remains of matured character of individuals of less civilized
races. And, looking at the forms of life which have
them save a few odd drawings and descriptions.
successively distinguished the epochs of the deve-
In the Nicholson flute the natural fingering loping world, this is the order, this the general plan,
only has been alluded to, i.e., that which gives in which with advancing time they have gradually
the best tone and tune. No reference is made to insensibly assumed more and more complex phases.
the "exceptional" fingerings, as they are only Nature," says Sydney Smith, "has not formed
used to facilitate rapid continuous passages, bril- man totally different from other animals, but rather
She has not, in his
liant effects, &c., and are quite inadmissible in added to his brain new organs.
the sostenuto.
case, pulled down the fabric of sentient being, and
reconstructed it upon a totally different plan. All
that she has done has been to add to the original
edifice Corinthian capitals and Doric columns; be.
stowing reason, not to supersede, but to guide, direct,
and perfect his animal nature."

flute.

(To be continued.)

The Phonophthalmotrope is the name of a new machine for elucidating the movements of the eye-ball. Its inventor is Dr. Donders, of Utrecht. By its help, the mathematical analysis made by Prof. Helmholtz of the ocular movements inay be practically demonstrated.

The whole course of the world's history has been

From a treatise entitled "Force v. Organization," in St. Cuthbert's Magazine.

an uninterrupted evolution from the fre
to this last. The first forms of exists
the life that was to follow, as the child is frat
the man. That life was potential then; it is arm
now.
The character of the future forest is me
in the molecules of the first acorn. Da
ist ein Gedanke Gottes-the Universe isat
And seeing how this life-scienc
of God.
globe has "unhasting and unresting." hr
numbered centuries, followed the appointed
how, in spite as it were of the agencies the
lifted or submerged continents, that have d
myriads of individuals or wrought strange
the forms that succeeded them,-how, not
ing the ravages of earthquakes and temp
conflicting forces of fire and of deluges t
made or marred the surface of the globe,—t
has fulfilled the stern decree of its des
solved in the growth of every germ and
moment the problem of all its existence,
but regard that existence as the embo
the realizata
a thought, that growth as

idea.

Further, the whole life of the human rao which comprehends not only those lesst completed in the life and death of all those beings that have lived and died since the pearance of man until now, but also in number of those larger cycles which have beginning and their end in the rise and dr nations; and in these we may perceive, in like: ner, the growth and decay of families and triks But the laws of the existence of the sil ism is, as we have seen, the same as that d They too are grade vegetal and animal one. evolved from simple, crude beginnings to the ne complex phases of their organization "PROSTOM therefore, is not an accident, but a necessity stead of civilization being artificial, it is a part nature-all of a piece with the development of the embryo and the unfolding of a tower. The modifications mankind have undergone, and are still undergoing, result from a las joriyng the whole organic creation."*

If, again, there be "one mind sees to all ind vidual men;" if "the genius ad creative principes is to be interpreted by, because involved of all eras in, the mind of that individual stall best embody the genius and results of her, if the sports in the development of the race bath LVI. part, as we have said, in the years with a p the life of one man, and the tendency of grat civilizations, Jewish, Egyptian, Greek, Botan, &c. be read in the thoughts and aspirations of child. hood, youth, and manhood, then de become the key to the whole history of the world the laws of the human mind become trasheathed in the facts and systems of the geologist, as well whe facts and epochs of human history; then at the course of man's development involve the presegles of all development whatsoever.

Now, we do not wish to shut our eves to the difficulties which lie in the interpretation of great problem of the development of life globe. We know full well all that may be e against our generalization; but it is becaus know these things, because we perceive that the are a multitude of facts seemingly more ime cilable with it than any we have ever seen siste but which we trust to show are in accordance it, that we have put it in the way we have da We have transferred the great problem of genesis and development of life in all its fors that of human life, as the microcosm which inv the principles of all. But are there no dit 17 here? Has humanity no problems left uns in that which concerns itself, its on life, i development?

Allowing that the development of life on the C has been a continuous evolution, as we afire. the method of this progression must not be 25 derstood. It does not imply that the highes of one class are intimately related to the l forms of another; that if Invertebrates pr Vertebrates, or Molluscs Crustaceaus, in th of the developing life of the globe, in such as we have stated, our theory by no means that the highest Invertebrate should giv the lowest Vertebrate, the highest Molluses**, lowest Crustacean. In considering the pros civilization, the Roman succeeded the Greek, English have come after the Roman, but this was not imply that the Roman was developed frus Greek, or that the Englishman is a lineal descendes: of the Roman. They each take their rise from tinct centres. The ancestry of each may be traced back to a remote past; and the predecessor of th Roman was contemporaneous with the ancestors d the Greek of the age of Pericles, and the ancestors of the Englishman of the nineteenth century with the age of Augustus. It is precisely the same with the history of animal life. In what remote past the ancestor of the exogenous plant or of the verte brate animal may be discovered, it is left for science to determine.

Now, the same law holds good even of the different species of any class. Take that of the Mollusca, for instance. One, perhaps, that comprises at pre

* H. Spencer.

Moreover, our generalization does not imply that Batrachians or Reptiles of some preceding epochs were less highly organized than those which exist in our own. Nay, rather the contrary; that such have been as a class more highly developed than any contemporary with man, as presenting under more generalized forms certain affinities to higher types.

Such organisms had their special epochs in ages anterior to that of intellectual man. Further, though vast numbers of organisms once coeval with molluses on our globe, and possessing a similar low type of structure, have yet in the course of ages undergone extraordinary changes -have progressed, as we say, to higher types, -yet vast numbers of others remain much the same as they were thousands of years ago. Yea, even such as they were in those primary strata, wherein we find almost the beginnings of the world's life. And have we no "persistent types" of humanity? None in that Eastern portion of the globe to which all history and tradition point as the cradle of the race?

COLOUR AND BRIGHTNESS OF THE
MOON'S SURFACE.

THE

point to which all our arrangements converge is this, and adjoining areas to the west. The contrast of
that a certain amount of force is involved in every the general colour of the surface hereabout, as com-
organism, and that for every step in higher organi-pared with that of the grey plains-its mottled and
zation which it gains in its development, an equiva- rugged aspect arising probably from its altered
lent of power is lost.
character from that which it possessed at a still
earlier epoch-the absence of that sharpness of out-
line in its remaining mountain-peaks or ranges so
characteristic of those which we find nearer to and
often on the grey plains, together testify to a much
earlier epoch than even that of the production of
the partly filled rings on the grey plains. Bright
white glistening surfaces, more or less in the
neighbourhood of bowl-shaped craters and dark
patches of a deep grey, approaching black, appear
alike to indicate the most recent formations; the
first, it may be, from loose fragmentary incoherent
materials ejected from adjacent craters, the last
from substances in a state at least of comparative
fluidity which have escaped from the interior
reservoir at the time of eruption. Phillips compares
the bright glistening region of Aristarchus to one in
which white trachyte abounds, and many of the
basalts in terrestrial volcanic regions present a dark
colour. Between the brightest and darkest of such
limited areas on the moon's surface every gradation
of intermediate tint occurs; and from a careful con-
sideration of the physical aspects of those regions
which, on the one hand, reflect considerably less
light than the brighter, and, on the other, con-
siderably more than the darker, it may be inferred
that such regions are amongst the most ancient of
lunar formations."

HE following extracts from Mr. Birt's letterpress to the fourth area of the Lunar Map are interesting in connection with an unstudied region of the moon's disc which has every appearance of being very ancient, and to have received its external characteristics long anterior to Chacornac's epoch of the production of the smaller and more perfect craters and blow-holes. It is also probable the reader may discover indications of the basis of a theory, which, if built up from telescopic observation and the study of photograms, may intelligibly explain many of the difficulties which now beset selenographical research.

sent more individuals than any other (save, micro-
scopical organisms), which for thousands of years
was the dominant type of life on the globe, as shown
by the remains imbedded in its rocks by myriads.
The cuttle-fish is generally held to be the most
highly organized representative of this sub-kingdom,
and its appearance on the earth, or that of forms of
the same species strikingly similar, is much later
than that of the less highly organized individuals of
its division. More, according to the best authorities,
even the lower or less specialized members of the
family to which it belongs (the Cephalopoda) are also
prior to it in point of time, and these much resemble
the group (Gasteropoda) considered inferior to it in
point of organization. But although one Gastero-
pod, or many, may have undergone modifications in
the course of time, which presented in the end more
resemblances to a higher species than to the one to
which it or they originally belonged, the theory of
progressive development by no means implies that
that course was necessary. And so, generally, we
may trace back the history of animal or vegetable
species on a thousand different lines, but on each
the less and less developed organism manifests "In numerous portions of the moon's surface, as
greater resemblance to the immature forms of other on that of the earth, we behold the results of the
superior organisms, or to the permanent forms of operation of two opposing forces, one by which the
inferior ones. The educated Englishman of to-day features are moulded and, as it were, built up, im-
presents many distinctive points of character-parting to the objects so produced an aspect of
differs much from the Frenchman, German, Italian, freshness that it is impossible to question their
Spaniard, &c.; but step by step, as we go back, these comparative recent production: the other, by which
differences become less and less apparent; and, objects once possessing all the characteristics of a
some two thousand years ago, who could have recent formation have yielded, it may have been
defined their several ancestors among the bar- gradually, to surrounding influences, whatever they
barian inhabitants of the forests of central Europe? may have been, so that at the present time they
How little did these again differ from the ancestors exhibit the semblance of vast ruins, which in some
of the Romans! Similarly, classes of Englishmen localities are unrelieved by even the slightest indi-
at present vary greatly; but the forefathers of some cation of the operation of a force of an opposite
of our proudest noblemen, at one time, were very character.
similar to ploughmen and mechanics-not to go "Webb, in his very masterly paper on the moon,
lower.
in Fraser's Magazine for September, 1868,
p. 381, speaks of the possibility that the colossal
lunar formations may have been the result of forces
acting in a more gradual manner, and with less
temporary vehemence than may seem to cor-
port with the term explosion. It may be that
astronomers have paid much more attention to
those lunar features which are clearly the results
of explosive action, than to those which manifest
the presence of a degrading agency. It has been
considered that many of the larger forms have been
produced by rapid, violent, and tumultuary pro.
cesses; and however true this view may be, it is
certainly inadequate to account for the present
appearances of still larger tracts in which no ex-
plosive outburst of an epoch which may in any
sense be called recent occurs. Nearly filled as well
as broken rings, interrupted mountain-chains, com
paratively smooth tracts without any well-defined
boundaries, are characteristic of such regions; and
it may be asked, in what manner and by what
agency have they attained their present condition?
Has the 'erosion of Chacornac destroyed the
Space prevents our considering further these missing portions of the broken rings? and has this
analogies, as also some problems touched on in the 'erosion acted suddenly or gradually? Has the
articles on classification just referred to, but to the diluvial,' restricted by Webb to the expression of
main difficulty which there presented itself we must comparative fluidity, independent of the nature of
devote a few lines, for it is the point we have had in the material, invaded and nearly filled previously
view in writing these articles, in fact it is their deep craters so as to furnish a connected series of
raison d'etre ! Having decided that vertebrate well-known forms, from the smooth-floored walled
animals were from one point of view higher than plain to the just perceptible ring above the surface?
invertebrate, yet we found that the bee belonging Has this same diluvial buried the lower portions
to the latter, on every principle on which humanity and the lateral spurs of continuous mountain-chains,
bases its judgment of superiority, was higher in the so that now the higher portions alone remain as
scale than some individuals belonging to the higher low, short, and detached ranges in the original line?
type. That, generally, structure could not be taken One cannot help contrasting the continental region,
as a mark of superiority. That, in deciding the to use a terrestrial analogy in which this area IV An
relative rank of different organisms, their proper- occurs, with the magnificent chains of the Apennines
ties, functions, &c., had to be taken into account, and Hamus, and the lower and smooth levels of
and that since these were different in different the Mare Imbrium and Mare Serenitatis, as exhi-
species, there was no common ground of compari- biting in a very marked degree the results of the
son. Will not the study of humanity throw light forces already mentioned. In the latter we see the
on this question? Is the Englishman, although effects of comparative recent action in the produc-
later, more complex in his organization, superior in tion of vast mountain-chains and the neighbouring
all respects to the Greek or Roman? All develop- extensive level plains. In the former these grand
ment, we say, is analogous to human development; features are wanting. The surface, although far
the eras of history to the phases of the growing from being smooth, as that of the Maria, is
mind, and these again to the epochs of the growing roughened only with the remains of former moun-
world. That progression is from the simple to the tains, rings, and craters; the degrading agency,
more complex we allow; but is the more complex whatever it may have been, appears to have
the more perfect? In the individual, is it the operated almost unchecked in this region, and it is
innocence of childhood, the enthusiasm of youth, a subject of interesting inquiry as to how this state
the strength and intellect of manhood, or the judg- of things has been effected. Has the filling up, has
ment of age, which constitutes the more perfect the wearing down (if such is the case) been gradual?
phase? What is that "sense of something lost' and what forces have been concerned in producing
which haunts the growing man, and which asserts the mutilated forms we now observe?
itself in the instincts of the race? Intellectually, "Brightness and colour may ultimately become
humanity has advanced; but does it not suffer some keys by means of which a better acquaintance may
compensation for the advantages it has gained? be obtained with the chronological sequence of
Is intellect the sole criterion of perfection? Lan- lunar formations. Chacornac refers the great
guage again is undoubtedly more complex now than
in the time of Shakespeare, but can our abstract
terms stimulate the imagination, rouse the passions,
sway humanity like the simple ones?
Is our more
complex language then as perfect as when less
developed? But that word "perfect" is vague and
indefinite. Who has the true type of perfect? or
who, having it, can demonstrate to his fellow-men
that his is the absolutely right one? In our own
opinion, the more complex is not the more perfect.
But opinion is an unstable and variable thing; the

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continental formations to an epoch anterior to that
of the production of the great plains, this, again,
being anterior to the period of explosive energy
contributing to the existence of numerous objects,
such as bowl-shaped craters and smaller blow-holes,
within the interiors of which no intrusive matter is
found. Reference, however, is not prominently
made to objects in mountainous regions similar to
those which we find in various portions of the great
plains-viz., partly buried craters and partially
destroyed rings, of which we have evidence in this

Indications exist in the region to which the above extracts refer, that its earliest state, so far as our present selenographical knowledge will enable us to judge, was very similar to many of the more recent districts in which perfect craters and mountainous regions intermingle. This was succeeded by the formation of a neighbouring grey plain, accompanied by the invasion of the craters on its borders and the breaking down of their walls facing the plain, remnants of which still exist. A further change posterior to the formation of the plain appears to have been marked by the elevation of a chain of low mountains in the locality of the craters which had been invaded.

TH

A NEW ANTISEPTIC.

THE hydrated chloride of aluminium, to which Mr. John Gamgee has recently drawn the attention of medical men and of the general public, appears, says the Lancet, to be a valuable antiseptic. It is quite as potent as chloride of zinc or carbolic acid, and is at the same time non-poisonous, and devoid of unpleasant smell of every kind. These qualities will no doubt ensure its being extensively used, and at no distant date we may expect it to displace the antiseptics which are at present in vogue.

It is somewhat strange that this substance should have been so long overlooked as a possible antiseptic, and Mr. Gamgee certainlydeserves credit for suggesting the utilization of it for this purpose. The reason why it has been passed over is probably to be sought in its not being a waste product in any common chemical manufacture. The anhydrous chloride of aluminium, which is manufactured in order to serve for the preparation of metallic alumi nium, is far too costly on account of the troublesome nature of the process by which it is prepared to wit, by passing chlorine at high temperatures over a mixture of aluminium and charcoal. By placing the anhydrous chloride of aluminium in water it is of course converted into hydrated chloride.

The most economical process for the preparation of the hydrated chloride of aluminium appears to be by double decomposition between sulphate of alumina and chloride of calcium (both of which are cheap commercial products). When solutions of these two salts are mixed together, sulphate of lime is formed and appears as a precipitate, whilst the hydrated chloride of aluminium remains dissolved.

On allowing the aqueous solution to evaporate at a very gentle heat and afterwards cooling, crystals of hydrated chloride are produced. If an attempt be made to drive off the water from the hydrated chloride by the application of heat, decomposition will take place. Hydrochloric acid is evolved under these conditions, and oxy-chloride of aluminium is formed, and, by pushing the process, alumina is obtained as the ultimate fixed product.

A NEW GUN.-According to the Scientific Journal, of Philadelphia, there is in course of erection, on the east side of New York Bay, a gun that will throw 800 five ounce balls in one minute, to a distance of about two miles. The shot may be either red hot or cold. The gun is circular, and appears like two dises of heavy iron plate, about 4ft. in diameter; upon one side is a funnel to convey the balls through to the proper chamber, without cessation of firing or diminution of speed; the muzzle projects upon the periphery of the circular machine, and may be elevated or depressed at the will of the gunner by the trunnion upon which it rotates. The machine when worked by the latter, it will throw from five ounce may be worked by manual labour or steam power, and balls to eight pound shot and shell, thus making it a destructive implement of warfare.

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