in * ; of att ” { ET slated 9 1, oeublecats. | abet hrs tele st a¥ states Aro odd en that i et $46; Bey . oa {bry ite Ajay ay aul eit ‘ f a 5 _ if 2 a‘ , a, ie x ee ‘ er emcee yeti > tee ee, ce Wide! 4 ee er ee re) - a ITROGEN N ARTERLY JOURNAL OF SCIENCE, Cc DOUBLE SPHCTRA BY W. MARSHALL WATTS, D.Sc. No. XXIX, JAN, LST “* ty uns . or = 3 me yin i ha a 7 BRL, miei aaa 26 LEN CE on: f i any wt ean A tlle ohne TOM Ad FI e mn = SPRCTR 4 apiy des pe pe es atte. nce a Ge el =. Che Spec abe Bat Pec ras gr Hieialy. in Rie pest: ies a ie a ’ et " an 4 ° hee: y ° é “ x , te "WAS tas . % THE QUARTERLY POURNAL OF SCIENCE. TANUAKY, 187=, I. ON DOUBLE SPECTRA. By W. MarsHaLt Watts, D.Sc. 7 is now just ten years since the first principles of spec- il trum analysis were enunciated by Bunsen and Kirchhoff. It would, probably, be difficult to find any ten years in the history of science which have yielded such a glorious harvest of results. In these ten years we have not only become acquainted with four elements, constituents of the earth’s crust, whose existence was previously not even suspected, but we have been enabled to extend our analysis beyond the earth, to far distant stars, and to learn the composition of our sun and of other suns, whose distance from us is so great that, in comparison with it, the immense space which stretches between the sun and the earth sinks into insig- nificance; nay, more, we have been able to detect star- motions, which it is beyond the power of the telescope to reveal—have gained extensive and important insight into the physical constitution of our great luminary, the sun, since the spectroscope enables us to observe any day, at leisure, phenomena which, without the spectroscope, can be studied only during the rare occurrence of a total eclipse, and are even able to look back into past time and to trace the history of the system of which our planet forms a part. But we have in these’ten years not only learnt new modes in which this mighty weapon of research may be employed, but have also made not less important progress in other direCtions, viz., in the establishment on sure ground of the principles on which the analysis rests, and in the definition of the precise conditions under which it is applicable. It must not be forgotten that every conclusion to which experi- mental science comes is a result of induction, and the danger of too hasty generalisation is manifest when we come to work with principles so potent as those of spectrum analysis. If, for example, we conclude because the spectrum of solar light contains a dark line of the same refrangibility as the dark line which can be obtained artificially in the spectrum of incandescent sodium vapour, that the sun’s atmosphere VOL. VIII. (0.S.)—VOL. I. (N.S.) B 2 On Double Sphectra. (January, contains sodium, we obviously assume that no other sub- stance but sodium ever gives a line of that precise refrangi- bility. Or, again, if knowing that under circumstances similar to those under which sodium vapour produces a dark line in the yellow, potassium vapour gives a dark line in the red, we conclude, from the absence of this line in the solar spec- trum, that potassium does not exist in the sun’s atmosphere, we tread on still more dangerous ground; since, in order that our conclusion may be legitimate, it is necessary that potassium vapour under no conditions that may exist in the sun should ever give any other spectrum than that containing this dark line. Or, to take still another example; if we find from our experiments that incandescent solids produce continuous spectra, while incandescent gases produce dis- continuous spectra, and therefore conclude that the nucleus of the sun is an incandescent solid, our conclusion becomes no longer tenable when it is shown that, under high pressure, gases also give off continuous spectra. It is proposed in this paper to describe some of the excep- tions to first-enunciated broad principles which, though unsuspected at first, have been shown to exist since spectrum analysis has been known as a separate method of research. Professors Bunsen and Kirchhoff, in their first memoir on spectrum analysis, describe the spectra of the metals of the alkalies and alkaline earths. They endeavour to establish firstly, that the speCtrum is the same whatever compound of the metal is employed. If a bead of sodium chloride be brought into the Bunsen flame the spectrum will con- sist of two yellow lines only, and will remain the same if the sodium chloride be exchanged for sodium iodide, or sodium sulphate, or sodium carbonate. A -second con- clusion arrived at in the same memoir is that the position of the bright lines is independent of the temperature to which the vapour of the substance is heated. Professors Bunsen and Kirchhoff found differences of intensity only when they employed, instead of the ordinary Bunsen flame, the flames of sulphur, carbon disulphide, carbonic oxide, hydrogen, or the oxyhydrogen flame. They also compared the flame-speCtra of sodium, lithium, potassium, strontium, and calcium with those obtained when the spark from an induction coil was taken between wires formed of the respective metals, and convinced themselves that the bright lines of the flame spectra were present in the same position, although other lines were seen which they supposed to be: due to foreign metals present in the ele¢trodes, and to the nitrogen of the air. Professor Kirchhoff expresses his opinion 1871.] On Double Spectra. 3 that, although the appearance of the spectrum may be very different under different circumstances, yet the position of the lines does not depend on the temperature. ‘“‘ Even the alteration of the mass of the incandescent gas is sufficient to effect a change in the character of the spec- trum. If the thickness of the film of vapour whose lines are being examined be increased, the luminous intensities of all the lines increase, but in different ratios. The intensity of the bright lines increases more slowly than that of the less visible rays. The impression which a line produces on the eye depends on its breadth as well as its brightness. Hence, it may happen that one line being less bright although broader than a second is less visible when the mass of incandescent gas is small, but becomes more dis- tin@tly seen than the second line when-the thickness of the vapour is increased. Indeed, if the luminosity of the whole spectrum be so lowered that only the most striking of the lines are seen, it may happen that the spectrum appears to be totally changed when the mass of the gas is altered. Change of temperature appears to produce an effect similar to this alteration in the mass of the glowing vapour, no deviation in the maxima of light being observed, but the intensities of the lines increasing so differently that those most visible at a high temperature are not those most readily seen at a low temperature.” These conclusions of Bunsen and Kirchhoff are now known to be true only within certain limits. The spectrum of a substance may be very considerably altered by change of temperature, and these changes in the spectrum do not consist merely in the alteration of the relative intensities of the lines, but are caused both by the addition of new lines and by the actual disappearance of lines present in the spectrum produced at the lower temperature. We have in the lithium and sodium spectra examples in which the change caused by increase of temperature consists simply in the addition of new lines, and the higher the temperature the greater becomes the complexity of the spectrum. A bead of lithium chloride in the Bunsen flame gives a spec- trum consisting of only one red line, whose wave-length is about 6684 ten-millionths of a millimetre, which cor- responds to 32 of the scale to which the spectra accom- panying this article are drawn. If the temperature be slightly raised by employing the blowpipe, an orange line at 443 (wave length, 6107) makes its appearance. At the higher temperature of the oxyhydrogen jet a blue line at 105 (wave length, 4605) is added, while at the intense temperature 4 On Double Spectra. (January, obtained by using the electric light the spectrum gives a fourth line at 86. The sodium spectrum at the temperature of the Bunsen flame consists only of the double yellow line of the same refrangibility as the solar line D, but if the sodium compound be ignited in the electric arc the spectrum contains four other lines, each also double. The high temperature spectrum of sodium is represented in Fig. 1, on the plan proposed by Bunsen. The position of the bright bands on the illuminated millimetre scale of the spe¢troscope is shown by the position of the black lines, while the intensity is indicated by the relative height of the lines. In regard to the other conclusion of Bunsen and Kirchhoff, that all compounds of a metal give the same spectrum, we now know that this is true only if the metal is one whose compounds are decomposed even at the low temperature of the flame. It is well known that a sufficiently high temperature causes the decomposition of many chemical substances into their elements, and that these re-combine when the temperature is allowed to fall again. ‘Thus, sodium carbonate and sodium nitrate give the same spectrum, because each is decomposed in the flame yielding metallic sodium by the incandescent vapour of which the yellow line is produced. But we have compounds which do not split up into their elements in the flame, although they are decomposed in the intense heat of the electric spark. Such a substance is copper chloride, which volatilises in the flame without being decomposed, and gives a spectrum which is altogether different from the true spectrum of copper obtained when the electric spark is allowed to pass between copper poles. There is no doubt that the spectrum is that of the com- pound copper chloride. Fig. 2 shows this spe¢trum com- pared with that of copper. The spectra of barium, strontium, and calcium show differences at different temperatures, which are probably to be explained in the same way. A reference to Fig. 3 will show the great difference observed when the calcium spec- trum is produced by taking the eleCtric spark in an atmo- sphere containing calcium, and when it is produced by bringing a bead of calcium chloride into the Bunsen fiame. Figs. 4 and 5 show the spectra of strontium and barium respectively under the same circumstances. It is sup- posed that in the flame spectrum the incandescent sub- stance to which the lines of the spectrum are due is calcium or strontium oxide, so that we have the spectrum of a compound, but when the electric spark is used, the 1871.] On Double Spectra. '5 oxide is decomposed, and we have the true spectrum of the metal. It should be remarked here that the true metal speCtrum consists invariably of sharply defined lines, while a compound gives a spectrum containing broad bands, which show a family resemblance amongst themselves and are often repetitions of each other. ‘This is seen in Figs. 2, 3, 4,and5. ‘The spectra of those metals whose salts are easily decomposed in the flame—for example, sodium, lithium, and thallium—give spectra containing only lines, and the only change producible by increase of temperature is the addition of new lines, while, in the case of metals whose salts are not so easily decomposed, the increase of tempera- ture not only adds new lines, but also splits up the bands into groups of fine lines. We observe the same thing amongst the non-metallic . elements in the case of cyanogen. If the flame of cyanogen burning in air be examined with the spectroscope, a magni- ficent spectrum is seen, which is obviously made up of two different spectra; one stretching from the light green into the blue exhibits a series of groups of lines, in each of which the brightest line is towards the red, and each group fades away on the side towards the blue; but the red end of the spectrum shows a series of groups of lines of exactly the opposite character—the brightest line of each group being on the side towards the blue, and each group fading away on the ted side. We shall see afterwards that the blue portion of the spectrum is due to the element carbon, but the red end is pro- duced by the compound cyanogen; and if the cyanogen be burnt in oxygen instead of air, the two of these groups most towards the blue become replaced by carbon lines, while if the gas be ignited by the electric spark, the whole of the cyanogen bands disappear, and the spectrum consists alto- gether of carbon lines. | It is a coincidence which doubtless has its own signifi- cance that, in all cases where by increase of temperature the - bands of the compound are made to give way to the lines of the element, the change takes place earliest in the blue end of the spectrum, and proceeds gradually towards the red. The flame-spectrum of strontium contains one line Sré of the metal which is seen also in the spark-speCtrum. The calcium flame-speCtrum also contains one line (135) which remains unchanged on increasing the temperature to that of the spark, and in both cases these lines of the metal terminate the spectrum towards the blue end.* The flame-spectrum *T owe to my friend Mr. Aldis the probable explanation of this peculiarity _as also of the way in which.the carbon bands shade off uniformly towards the blue. 6 On Double Spectra. [January, of barium contains no line of the metal, since barium oxide is less easily decomposed than either calcium oxide or strontium oxide. But amongst all the additions made to our knowledge of spectrum analysis within these ten years, none is so startling as the discovery, which we owe to Pliicker, that a substance may give two totally different spectra which have no line or band incommon. Ina paper published in the ‘‘ Philo- sophical Transactions” for 1865, Pliicker and Hittorf describe double spectra of nitrogen, sulphur, selenium, hydro- gen, and iodine. Nitrogen exhibits this peculiarity in a marked manner. In order to obtain its speCtrum it is neces- sary to employ electricity, as no flame is hot enough. If an ordinary vacuum-tube containing nitrogen have the current from an indu¢tion coil sent through it, the narrow part of the tube gives out a purple light, which is resolved by the prism into the spectrum represented in the chromo- lithograph—a spectrum consisting of an immense number of shaded bands. If, instead of using nitrogen at low pressures, we let the spark pass in the gas at the ordinary pressure, and intensify it by connecting the two wires with the outer and inner coatings of a moderate sized Leyden jar, we obtain an intensely bright light, which gives a spectrum also repre- sented in the chromo-lithograph. ‘This second spectrum is entirely different from the other, consisting only of sharply defined bright lines. Pliicker terms these spectra, spectra of the first order, and of the second order, respectively. It will be observed that these spectra possess, respeCtively, the The vibrations which produce light depend, so far as we can see, on the manner in which the atoms of a molecule are in equilibrium. We see from the occurrence of lines in all parts of the spectrum, that there are in the molecule several different vibrations executed simultaneously, and these corres- pond to the greater or less intensity of the force by which the atoms are main- tained in their position of equilibrium. The more intense the force by which an atom is held in equilibrium, the faster it will vibrate when set in motion. When cyanogen is moderately heated its molecules vibrate in the regular way indicated by the cyanogen spectrum; but when the temperature is raised the compound is dissociated, and the carbon atoms vibrate uninfluenced by those of nitrogen. Now, when this takes place, the vibrations of the cyanogen which first disappear must be those due to the closest intimacy—that is, the most rapid. Hence the carbon spectrum comes in at the blue end. Further, the vibrations of an atom about its position of equilibrium will not all be of equal length, and so will produce light of varying intensity. If the vibrations are quite cycloidal, all will be executed in the same time, and we shall have a sharp bright line, but if the vibrations are like those of an ordinary pendulum, the smaller vibrations will be performed inless time than the larger, and the result will be a band fading off into the blue. If, on the other hand, the vibrations of small amplitude are executed more slowly than those of larger amplitude, the result will be a band fading off into the red. 1871.] On Double Spectra. 7 characteristics of those produced by compounds and by elements. It remains for future experiments to confirm or modify the indication thus given of the compound nature of nitrogen. Similar results were obtained by Plticker with sulphur. In order to experiment with sulphur, a tube of difficultly fusible glass was employed. Sulphur was introduced into the tube, which was then completely exhausted. When the narrow part of the tube is gently warmed by a spirit-lamp, and the platinum wires are connected with the induction coil, a spectrum of the first order is obtained. It consists of thirty-seven well-defined bands extending from the red into the extreme blue. Seven lie between the solar lines c and D, eighteen between D and F, and eleven between F andGc. On heating the tube still more a quite different set of bright lines makes its appearance, and on introducing a Leyden jar into the circuit the second spectrum becomes fully established and notrace of the spectrum of bands remains. This second spectrum consists entirely of sharply defined bright lines— two red lines are especially noticeable, each of them triple. It is thus established that certain gases may, under altered circumstances, vibrate in an entirely different manner, and Pliicker believes that the necessary difference of circum- stance is simply difference of temperature, the spectra of the first order belonging always to the lower temperature. The Leyden jar increases the temperature of the gas, for it necessitates the accumulation of a larger quantity of electri- city preparatory to each discharge, so that the temperature of the spark with the Leyden jar is much higher than that of the simple discharge. Thus wessee that, on heating the sulphur-tube and employing the Leyden jar, the low tem- perature spectrum gives way to the high temperature spectrum. The spectrum obtained from an ordinary vacuum-tube containing hydrogen (under a pressure of 5 to ro millimetres), consists of three lines only—Ha, coincident with Fraunhofer’s line c in the red; Hf, coincident with Fin the blue; and Hy, nearly coincident with c in the violet. Pliicker, who first observed this spectrum (Fig. 6), described, in the paper already referred to, a second spectrum of hydrogen, corresponding to a lower temperature. This observation has been abundantly confirmed by important experiments, made since the date of Pliicker’s paper, by Prof. Wiillner, of Bonn; and his results are so remarkable that it will be well to describe them somewhat at length. His apparatus consisted of a vacuum-tube of the ordinary 8 On Double Spectra. [January, shape, which formed the upper portion of the shorter leg of a U-tube; thelong leg of which was about eight feet high. The spectral tube was connected by oneside-tube with the apparatus for preparing pure hydrogen, and by a second side-tube with a Geissler’s air-pump, by means of which any degree of exhaustion could be obtained, while, by pouring mercury into the long leg of the U-tube, the pressure could be increased up to about three atmospheres. Prof. Willner found that, using the discharge from an induction coil, the spectrum obtained varied essentially with the pressure. With the lowest pressure which could be obtained, the light in the tube is of a splendid green, like a thallium flame, and the spectrum does not contain either the red line or the violet line of Plucker’s spectrum, but consists of six groups of very brilliant green lines (Fig. 6, 3). At pressures of one, two, or three millimetres the speCtrum is the well-known one consisting of the three lines without any of the green lines; and upon increasing the pressure still further, another spectrum makes its appearance which contains Haand 6, but not Hy, and the space between He and Hf is filled up by a number of beautifully shaded bands, which also extend somewhat beyond H@; this spectrum persists till the pressure rises to about 400 millimetres. It is represented in Fig.6,2. Prof. Wiillner thinks that these different spectra of hydrogen are to be explained by differ- ences of temperature, and that the spectrum last described is due to a higher temperature than that which produces the spectrum of three lines. The results obtained with oxygen were quite similar. At the lowest pressure it gave a spectrum consisting of five groups of fine lines in the green and blue; at pressures of about one millimetre a second spectrum of broad bands; and at higher pressures a third, consisting of a great number of fine lines. Nitrogen, on the other hand, only gave the two spectra already described. The same memoir of Prof. Willner contains a description of two different aluminium spectra. Both were obtained by letting the spark strike between wires of aluminium, but the spectrum varied with the distance between the eleCtrodes. With a distance of about two millimetres the spectrum (Fig. 7, 2) consists of four green splendidly shaded bands, brightest on the side towards the blue, and each traversed by fine bright lines. When, however, the spark distance exceeded ten millimetres, a quite different spectrum was obtained, which is no doubt produced at a higher temperature. This eO7I.)*- On Double Spectra. 9 spectrum, which is represented in Fig. 7, 1, consists of a number of bright lines and groups of lines standing out from a feebly illuminated background. The changes of spe¢trum shown by the element carbon are, perhaps, as curious and interesting as any. At first sight it would appear that carbon is an element unlikely to yield a discontinuous spectrum, inasmuch as it is not known in the gaseous condition; and, that if we obtain discon- tinuous spectra from carbon compounds, they must be due to some compound of carbon. ‘Thus the bright blue lines observed by Swan (1856), in the spectrum of the Bunsen flame, might be supposed to be more probably due to carbonic oxide or carbonic acid than to carbon itself. But we find that these same lines occur not only in the spectrum of the flame, but also in the spectra obtained by passing the electric spark either through carbonic oxide, or olefiant gas, or cyanogen, and the lines thus found to be common to compounds of carbon with different elements must of course be due to carbon itself. Whether they are really produced by carbon in the gaseous state is a question which cannot yet be certainly decided. If the carbon is in the solid state we shall then have an exception to the law that incandescent solids give continuous spectra, of which we have only one other example, viz., the spectrum of bright lines obtained by Bahr and Bunsen from glowing erbia. In the case of erbia it is not impossible that the bright lines are really produced by a gas (Huggins and Reynolds, Proc. Roy. Soc., June 16th, 1870), and it is by no means improbable that, when a hydrocarbon is burned, it is first of all decomposed into its elements, which then combine with oxygen. If this be so the carbon may exist for the moment in the gaseous state. _ There exist no fewer than four spectra which are all probably due to incandescent carbon vapour. The first carbon spectrum is obtained when olefiant gas and oxygen are burnt together in an oxyhydrogen blowpipe-jet. The flame thus obtained exhibits a central cone of intense green, which, examined by the spectroscope, gives the spectrum first obtained by Swan, and ascribed by Attfield to the vapour of carbon. This spectrum, which is repre- sented in the chromolithograph, No. 1, is one of the most beautiful which can be imagined, and consists of five groups of lines—a in the red, yin the greenish yellow, 6 brilliant emerald-green, ein the blue, and f violet. Group a contains five lines, of which the third is the brightest. y contains seven, of which the least refracted is VOL. VIII. (0.S.)—VOL. I. (N.S.) © Io On Double Spectra. [January, the brightest, and each succeeding line is less brilliant than the one before; so that the group rises sharply out of dark- ness on the left, and fades gradually away on the right. The group 6, which contains four lines, presents the same gra- dation of intensity; e contains four lines of nearly equal intensity, the fourth being double; and f consists of a broad band, then a fine bright line, and then a band fading away on the most refracted side. When the spectrum is obtained very brightly, there may be observed in addition six very fine bright lines of equal intensity, which gave the readings 86, 87°5, 89, 91, 93, 95. The band 128—133 is also seen to be shaded by a large number of nearly equidistant fine dark lines; and the least refrangible band of the group f (1z1—126) is resolved into lines. This spectrum may be obtained from the flame of any hydrocarbon, though in many caess, owing to the faintness of the spectrum, only some of the groups can be recognised. In the flame of an ordinary Bunsen burner 6 and ¢ are easily seen, y and f are much fainter, and the red group cannot be detected. When the temperature is sufficiently high, we have, instead of the group f, two other groups, € and 0, which are also represented in the chromolithograph. Group € contains seven lines (105—113) and group @ contains six (136—1I42). The lines of the second carbon spectrum were first observed by Plticker in 1859, and supposed by him to be the lines of the compound carbonic acid, but the fact that they really constitute a spectrum of carbon, since they can be ob- tained either from carbonic oxide or from olefiant gas, was. first noted by Roscoe in 1864. This spectrum is represented in Fig. 2 of the chromolithograph. The third carbon spectrum is that of the flame which issues from the converter in the Bessemer steel process, in which air is forced through molten iron. It is represented in the chromolithograph, Fig. 3, and is remarkable because it consists of groups of lines, in each of which the brightest line is the most refrangible—an aspect which is exactly the reverse of that so noticeable in the ordinary carbon-spectrum, where each group has its strongest line on the left hand. These lines are unquestionably produced by carbon in some form or other. They disappear when all the carbon has been burned out of the iron, and their disappearance forms the most delicate test by which to determine the right point to stop the blast. The fourth carbon spectrum is obtained when the spark from an induction. coil _is taken in carbonic acid, andua THE QUARTERLY JOURNAL OF SCIENCE. No. XXIX., JANuARY, 1871. 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THT iT Ty Coos ny oe TA oer wee eae ee ee a Ce a ene | | 1 2 3 4 5 6 ai 8 is 13 14. 15 16 17 EF a 0 10 lm 12 ae ae ee Boerne Ty) ||| ne eal Pea |e et ee aa ge a Th ia a os ee ee Se ecg ie 3 Ts OD ee 0 Z rR 3 4 i: 6 if I: li 10 va) 12 [ 14 1s le yf 18 3. foropm PVN punt et A ela pa ea (tb ytiul Pybbyetrtyins Les tomsces | ee aes dyes es NRL Dag a A Bre cle aa Pe 0 le L 3 4 \s 6 7 lg 9 I u 3 1h a IG la B Vf 1 All. Mui aa Pyyr pyr ro PU A CO a Haag pee OD oe a Se aaa a ea enn ee Be i 1 he F 4 5 [ 7 9 be lL: e ns 4 15 Las 17 B Al 2. OO Ooo yA a Po on pect l, 3 a ae tt Pr atts LA NC PP BN RE I la J | l; | 9 I ie lz2 le 4 Ls gs ie hn 1871.] On Double Sphectra. 13 Leyden jar is included in the circuit. The spark without the Leyden jar is not hot enough to decompose carbonic acid, and gives in that gas only a continuous spectrum. In car- bonic oxide (which seems to be more easily decomposed) it yields the first carbon spectrum, but when the Leyden jar is employed, both gases are decomposed with deposition of carbon, and give the same spectrum. This fourth carbon spectrum (represented in the chromolithograph, Fig. 4) is one of Pliicker’s ‘‘ spectra of the second order,” consisting of sharply defined lines, often in pairs, and is no doubt produced by carbon at an extremely high temperature. The attempt to ascertain the circumstances under which these four carbon spectra are produced, has led to a result which, if it can be maintained, is of the greatest interest. We have seen that the explanation given of the different spectra of hydrogen is that they are produced by the gas heated to different temperatures, and there is no difficulty in conceiving that the particles of a gas may vibrate differently when the gas is differently heated. We have only very rough means of measuring high temperatures, and the de- termination of the temperature to which the gas in a flame is heated can only be approximate. It is true that we can calculate the temperature of a flame from the known | amount of heat given out by the gas in burning, but these results are always too high, in consequence of conditions which it is impossible to take into account in the calculation. We have, however, one or two experi- mental determinations of value. Deville and Debray have determined the temperature of the oxyhydrogen flame by heating a mass of platinum to the highest possible tem- perature in a crucible of lime, and then plunging it into water, and determining the temperature to which the water is heated, and find in this way that the temperature is not higher than 2500 C. Bunsen, by a quite different method has found for the same number 2800° C., which, considering the difficulty of the determination, agrees satisfactorily with Deville’s result. Bunsen has also found that the tempera- ture of the flame of hydrogen in air is 2024°, of carbonic oxide in air, 1997", and in oxygen, 3033°, and of cyanogen in air, 3297 C. Deville and Debray have also determined by their method the fusing point of platinum, which they find lies between 1800° and 2000° C. The first carbon spectrum is obtainable from flames which cover a considerable range of temperature. It is given by the blue cone of a Bunsen flame, the temperature of which is not high enough to melt the finest platinum wire, and must 14 On Double Spectra. _[January, therefore be less than 2000 C. It is also given (with the addition of the groups ¢ and @) by the flame of cyanogen in air, the temperature of which we have seen to be 3297°, and by the flame of cyanogen in oxygen, which is the hottest flame known, and is probably at least 5000 or 6000° C. We see thus that the lines of the first spectrum are given by carbon heated (at any rate) between 2000° and 3000 C. Now it can be shown that the second carbon spectrum can also be produced by carbon heated within the same range. This second spectrum is not obtainable from any flame at all, but is produced by the ele¢tric discharge in either car- bonic oxide, or olefiant gas, or carbon disulphide. We have seen that the sodium spectrum contains, when the temperature is sufficiently high, besides the well-known double line, four other lines, each of them double; Na6 at 56, Nay at 75°5, Nad at 83°2, and Nae at 43. In the Bunsen flame, the D lines only are obtained; but, if the tempera- ture of the flame be increased, these other sodium lines come out one by one, and in the order given above, Na@ becoming visible almost precisely at the temperature at which platinum melts—that is, 2000° C.; so that, if a bead of sodium carbonate be brought into any flame incapable of fusing platinum, only the D lines will be seen, but, if the flame be hot enough to fuse platinum, Nag will also be visible. For example— The Bunsen flame gives the D lines only, and is in- capable of fusing platinum. The flame of coal-gas, fed by a jet of air mixed witha little oxygen, gave Naf, but not mek The flame anes platinum easily. The flame of carbonic oxide in air (temperature, ape C.) gave only D; it is incapable of fusing platinum. Carbonic oxide fed by oxygen (temperature, 3033 C.) gives Naf and Nay. We conclude, therefore, that Naf indicates a temperature of at least 2000° C., and that Nay comes out about 3000 C. If now the discharge of an induction coil be passed through a Geissler’s tube containing carbonic oxide into which some pieces of sodium have been introduced, the carbon spectrum No.2 is obtained; and if the sodium be volatilised, the sodium lines come out one by one as the tube gets hot, and the carbon lines are seen simultaneously with Na, and (at first) without Nay. Hence we conclude that this second spectrum is also produced by carbon between the temperatures of 2000 and 3000 C., and we are therefore 1871.] On Double Spectra. 15 unable to ascribe the differences observed to difference of temperature. om The conclusion drawn from this experiment appears. to open up new views of the cause of double spectra, and to demand further investigations which may throw light on the molecular constitution of gases. We know so little about the mode in which those vibrations of the atoms of a gas take place by which light is produced, that it eon Ol much use to speculate: on the causes of the difference of light emitted at the same temperature. We know, indeed, that heat is caused by the motion of the molecules of a gas, and that the faster they move the higher is the temperature of the gas. If the vibrations which con- stitute light are executed by the constituent atoms of the molecules, it is possible that the atoms may vibrate dif- ferently, although the motion of the molecules is the same— that is, the light emitted may vary, although the temperature is he same.* Further experiments may enable us to distinguish between the effect of change of temperature and change of pressure. It may be noted that the second carbon spectrum has been obtained only from gases at pressures less than 100 m.m., although the first carbon spectrum (which is produced at the Same temperature) can be obtained either from gases at low pressure or at high pressure. It is understood that Messrs. Frankland and Lockyer are engaged in experiments which will throw light on this subject. * If this supposition is corre@, increase of temperature ought to cause the lines of a spectrum to expand, since, in the motion of a molecule towards the observer, the refrangibility of the light it emits ought to be increased, and in the opposite motion ought to be as much diminished, The expansion which the lines of hydrogen undergo under increase of pressure is, however, too great to be accounted for by any possible consequent increase of temperature. (16) [January, II. THE GREAT PYRAMID OF EGYPT, FROM A MODERN SCIENTIFIC POINT OF VIEW. By C. Piazzi SmMytuH, Astronomer Royal for Scotland. Part I. Hearing, discussing, and disposing of the older claims, of History (as hitherto written), Archite@ture, Archeology, Egyptology, Progressive development, ‘* Theotechny,” and the British Museum, to explain any of the chief data of the Great Pyramid. 1. Touching the General Status of both the Structure and its Primeval Authors. >G ELDOM does a practical astronomer occupy himself “SY much with matters of very high antiquity ; and why should he, or what improvement is he likely to gain in his own art by studying what has descended from those dim, primeval times ? Truly great may the Greeks, so very generally taken as types of all that is grandly intellectual in antiquity, have been in esthetic appreciation, or as ethical writers; supreme, too, in that deceptive art, which, in the eyes of more than one of our living statesmen, has elevated Homer to a greater height than all his unrivalled poetry, viz., his ‘‘ Theotechny ;” but who amongst those ancients, whether Pelasgic or Hellenic, had any notion of measuring an angle in the sky with what we should call now even decent accuracy ? They are said, those Greek philosophers (and of course in the present enquiry mere Romans are too modern to appear at all), after their civilisation had gone on growing for several centuries, to have ascertained, about the date of 330 B.c., that the then Pole star, some 6° from the Pole, was not in the very Polar point. Butas to measuring its distance there- from down to minutes and seconds of angle, that was totally beyond their powers of comprehension, or even their very imagination of the possible. Not that they were necessarily inferior by nature to the men of the present day, in the improvable faculties to be exercised in that science ; but that that science or art, viz., angular measure, does not, and cannot spring into life full and complete at once like a Divine gift, for it is, par excellence, the choicest fruit of man’s own progressive development of his own powers through long succeeding ages of steady, undeviating, un wearied toil. 1871.| . The Great Pyramid of Egypt. 17 Hence, if we should desireto see with exactitude what really has been accomplished in the world of man, by that sometimes overpraised, sometimes under-valued, ‘‘ progressive develop- ment,” no better example can be studied than the history of practical astronomy from the date of Pytheas, of Marseilles, 2200 years ago, with his infantine tale about the Pole star, down to the present time, when—though even the most accom- plished observer is still separated from absolute perfection by difficulties which are always found to underlie, with even increasing pertinacity, every successive fraction of a second that man may be enabled to reach in his results,—just as invincibly, indeed, as a boundless ocean separated Newton and his philosophical discoveries among the mere pebbles of - his beach from the end of discoverable things,—yet a well- taught schoolboy may now measure an angle in the heavens to a degree of accuracy that the whole Grecian race, even in its day of plenitude, was perfectly incapable of. Quite certain, therefore, may we be, on continuing the observed rate of progress inversely backwards, that amongst all the Greek, and Latin races too, we need not look for anything respectable in practical astronomy, at or about 3000 years ago; less still at any earlier dates; and yet my task is now to direct my reader’s attention to a monument far older still than anything yet mentioned, or of more than 4000 years ago; and to show that it is one where practical performance was carried out with a degree of excellence, which may form a cynosure for emulation to some of the most skilled workers and learned thinkers amongst us still, even in astronomy ! In such case, of course this monument, the Great Pyramid of Egypt, is not Greek, nor Latin, nor Phoenician, nor even Assyrian. And if wewere toadd that it has nothing to doeither with ancient idolatry in any shape, orthe worship of false gods, or the vain glorification of any mortal man,—the results of the closest scrutiny yet made would entirely justify the assertion ; at the same time that it brought to light also overwhelming proof of an abiding and all-dire¢ting belief in the immortality of the soul, and a future judgment having then firmly obtained. Most essential is it to be warned on these points, because, while the Great Pyramid does in so far stand just within or upon Egypt; it is therefore by one class of unthinking persons at once confounded with and attributed to the inventions of those long subsequent, but still so-called *‘ancient Egyptians,” but of ‘‘the New Kingdom,” who formed the well-known Pharaonic despotisms of history, and VOL. VIII. (0.S.)—VOL. I. (N.S.) D ® 18 The Great Pyramd of Egypt. (January, who erected innumerable temples—marvels no doubt of colossal art, but teeming over all their surfaces with engravings and pictures of every kind of abominable animal- headed idol-god; and by another class it is equally, but erroneously, attributed to early ages of the world, when, according to the doctrine of progressive development rather strongly applied, it is believed that man could then nowhere have been in possession of any clear ideas of his soul’s life, of an eternal and all-wise Creator, and future bliss or pain transcending everything in this present world of trial. Wherefore, whoever the builders of the Great Pyramid were, and whenever they lived,—and it will be our business presently to endeavour to find out,—let no one fancy that with them he is in the presence of none but necessarily either rampant idolaters or miserable men entirely atheistic. 2. The Great Pyranuid the Oldest Monument in Egypt. Visiting in the present day the land of Egypt, that country so inimitably prepared by nature, with the mildest of climates and driest of atmospheres, to be both the perpetual store- house of human monuments and faithful keeper of historical records,—all travellers and all writers declaim on the almost perfect preservation of every document, even down to the * seals impressed by many centuries of kings on sun-dried bricks of Nile mud. Indeed there, with ease, backward you may step across the ages that are gone, and read on the later monuments records of the first wild rush of Moham- medan conquerors, issuing, 1200 years ago, locust-like from their Arabian home to purge out the idolatries of the Greek Christian Church degraded; then beyond that you may arrive at proofs of the Roman rule; beyond that, at Mace- donian Ptolemies, enervated and debauched in a southern climate; then the cruelties of Persian despots; then Egyptian kings, who fought over Jerusalem with Nebuchadnezzar and monarchs of Mesopotamian line; then the Theban kings, who revelled through long ages in idolatry carried to its worst culminations ; then to Sesostris and his supposed wars, but really oppression of Israelites in Egypt; then to Memphian kings who ruled the Delia-land mildly in the times of Joseph; then to older Dynasties among whose tombs some Pyramids are found; then up through many Pyramid- building kings to him at last, King Cheops, Suphis or Shofo, who built, or rather during whose reign was built, that Pyramid which all the world still calls the Great Pyramid. The greatest, too, it is of all the series of Egyptian pyramids; and, most passing strange to say, when with that quality, 1871.] The Great Pyramid of Egypt. 19 the first. Not only, too, the first Pyramid of all known Pyramids, but the first example of all known architecture in stone. Before that remarkable building, as we shall presently show from independent and impartial authority, there is no known monument in all Egypt; no material existing proof of the handy-work of man, unless it be some flint chips. A/ter that building comes everything of the hosts of acknowledged Egyptian remains, but nothing equal to it. The Pyramids subsequently built were all smaller, less perfect in mechanical construction, without science in design, and tending to meretricious in taste. The Great Pyramid is alone a perfect example in design and execution, both ezsthetically and mechanically ; and, as we are to show, it is the largest ; and it was the first. 3. The Superior Antiquity and Constructive Excellence of the Great Pyramid as Testified to by Egyptologists. Now, each and all of these features of the Great Pyramid are totally opposed to the favourite modern doctrine of ‘progressive development ;” and, whereas the methods of “‘scientising ” in the present day have been for long almost confined to looking out for some minute discrepancy, just perceivable in telescope or microscope, between theory and observation, and following up that little difference until its reason has been discovered,—what amount of attention ought not to be given by all engaged in any branch of anthropological science, to such an entire and confounding difference from theory as this; viz., that the first stone building ever erected by man, instead of being the smallest and worst, is actually the best and highest of all that have ever been erected on the face of the earth ! My readers will require some proof of these things; and though to set forth full proofs of the greatest marvel in all the general history of man, within the compass of one or two short papers, is totally beyond me, I will yet attempt something in the direction of at least showing what kind of data there are from which proofs may be extracted, if men would only apply themselves heartily to the task. And it may, perhaps, expedite our progress if I quote, whenever printed facts allow of it, not so much from my own observa- tions, as from those authors who hold opposite opinions to myself touching explanations and conclusions, but who are allowed by all the world to be deservedly great in practical Egyptology, or a knowledge of the monuments still standing 20. The Great Pyramd of Egypt. [January, in Egypt, and by means of their own examinations, readings, and measures. Thus, as regards that strange priority of the Great Pyramid to all other monuments of Egypt (and if of Egypt then of the whole world), what says Dr. Lepsius, the most experienced hierologist of the day ; but one who really cares little or nothing about the Great Pyramid on all the counts of the new scientific theory, because regular Egyptian hiero- glyphics of the late Theban date are his forte, and the most fearful pictures of revolting animal gods, the study of all others that his soul delights in; and these things he does not find in the Great Pyramid. Thus, then, on the one required point of superior antiquity, writes the famous Prussian savant, ‘*the hope of Egyptology,” as he was begun to be designated even in his youth. ‘Nor have I yet found a single cartouche that can safely be assigned to a period previous tothe fourth dynasty. The builders of the Great Pyramid seem to assert their right to form the commencement of monumental history, even if it be clear that they were not the jfivst builders and monumental writers.” And again,— ‘““The Pyramid of Cheops, to which the ve link of our whole monumental history is fastened immovably, not only for Egyptian, but for universal history.’’* And still again, but this time to come closer home, take the most literary architect of the day, or that has yet appeared in our literature,—James Fergusson,—whose soul ( likewise delights in the horrible details of such things as "{“ Tree and Serpent worship’? by immortal man, and in | degrading forms of idolatry which he persists in declaring, on mere /ypothesis, to have been necessarily the earliest forms of worship for all men on their gradually emerging, according to that hypothesis, by their own powers alone, out of a lower than merely savage condition. Even he then, our great zsthetical historian of the absolute and material, after confessing that— ‘‘No one can possibly examine the interior of the Great Pyramid without being struck with astonishment at the wonderful mechanical skill displayed in its construction.” And even adding to that,— ‘Nothing more perfect mechanically has ever been erected since that time.” * Dr. Lepsius’s “‘ Letters from Egypt in 1843.” Compare also the chrono- logical arrangement of Lepsius’s unrivalled collection of folio Egyptian litho- graphs, in the Denkmaeler. 1871.] The Great Pyramid of Egypt. 21 Yet even he is fain to allow that— “Stretch the history of architeCture how we will, we cannot get beyond the epoch of the Pyramid builders (of Lower Egypt).” Or, as another learned writer in the 6oth edition of a British Museum catalogue prints it— ‘“* The earliest known architecture, the Pyramids of the fourth Dynasty.” A few years ago, certain ruined masses amongst them were thought to be older than the Great Pyramid, the chief work of the said so-called or reputed fourth dynasty, and that Cambridge Humboldt of his day, the travelled Dr. Clarke, at the beginning of the century pronounced from his boat on the Nile that he could distinguish a long succession of earlier ages to that of the Great Pyramid, by the con- tinued approach in ther pyramids to a mere mound of soft earth. But as all the more signal of his examples have since then been positively proved by the disciples of Cham- pollion and his post-Clarkian science of hieroglyphical interpretation to have been built by monarchs of dynasties long subsequent to King Shofo of the fourth, and to owe their mouldering forms and subsiding masses to their having been built of perishable brick in place of lasting stone, the claim of the Great Pyramid to be the earliest builded monument that man can put his hand upon in the present day, is now almost, if not quite, universally allowed. 7 This claim, too, is equally good, no matter whether a long or a short chronology for Egypt and the East be adopted ; for, in so far depending, as we are now doing, upon, and giving ail honour to, the disquisitions of literary Egypto- logists, it is differential date only. The Great Pyramid itself, questioned on the scientific theory presently to be expounded, can declare its own absolute date with admirable exactness ; but in this first part of my paper a differential date is enough for our purpose, and I am anxious to make full use of whatever standard points have been ascertained in past years by the literary gentlemen, acknowledged leaders of Egyptology—good men undoubtedly, and very able, some of them, too, gifted with actual genius. Wherefore they conclusion as to the earlier comparative date of the Great Pyramid to that of any other known building, whether in Egypt or elsewhere throughout the known world, is a fact of the first magnitude, to be kept vividly before us during the whole of our present inquiry. 22 The Great Pyramid of Egypt. (January, 4. The Egyptologists versus the Ordinary Arguments of Progressive Development. In fact, the priority of date (whether it should eventually be proved absolute and entire, or just short thereof by a very few years, a mere nothing at this distance of time, and equally opposed to progressive development) is the beginning of the new theory of the Great Pyramid, the very key-note . of that grand and solemn story which its component stones have, and are able, to tell. For even thereby that building stands unique upon earth; there is not anything architec- tural so old elsewhere, and yet by modern archite¢ts, upon mere ordinary, superficial, but sound, architectural grounds, it 1s pronounced to be the best built monument ever yet erected, even down to these times in which we live. What conclusions, then, are we thence to draw ? What, indeed! For precisely at this point begin the utter antagonisms between the advocates of the new theory and the older Egyptologists. They, the Egyptologers, say (see Bunsen, see Fergusson, see Renan) ‘‘ because the Great Pyramid is so big and so admirably built, therefore infinitely long ages of slowly growing, improving, developing, architecture must have pre- ceded it.” Yet why therefore, and why must? ‘Those phrases depend merely on the human hypothesis of progressive develop- ment, combined with the gratuitous assumption of its having been the only nursing-mother or foster-father of the human race during all that. primeval period of unknown length, which preceded the first of our veritable historical records, and for, or of, which we have no mundane “material data. The new theorists, on the other hand, following out the ideas of the late John Taylor, of London, feel compelled to assert that, ‘‘if such long-continued ages of progressive architecture had preceded the Great Pyramid, the remains thereof, especially in such a monument-preserving climateas that of Egypt has already been proved to be, ought to, and would, have been found most extensively and abundantly, even to far outnumbering all the builded monuments that have been erected since. Yet the actual and admitted fact by every able man who has searched Egypt and the adjacent countries is,—after the Great Pyramid comes the date of everything of the architectural known; before it there is nothing.” The Egyptologers are perfettly aware of this profound - 1871.] The Great Pyramid of Egypt. 23 difficulty, and how do they treat it? Some of them with imperious coolness disdainfully ignore it altogether, and go on undisturbedly detailing to their willing readers long lists of paper kings, and the length of the years of their imagined reigns over a period of more than 10,000 years before the Great Pyramid. But a fully honest man, like James Fergusson, freely confesses the tightness of the case he finds himself shut up in, and ingeniously puts forward two attempted explanations—as thus :— ist. He hopes that the architecture of those very early and most lengthy theoretical periods will be discovered some Gay-, And,— and. He has a theory based on facts in his own science, that the first example of any new idea in architecture is always the finest ! The former reason, so little complimentary to the present state of our knowledge of the surface of the earth, may be safely left to itself: but the latter one touches a point wherein no one can cross or negle¢t Mr. Fergusson with impunity; and he lays down, not only that the earliest stone dome, as that of the Pantheon of Rome, 1s still the finest and largest of its kind existing, but that the first of the rock-cut temples of India is also the grandest of the whole series since excavated, and so with many other varieties of shrines. On which doCtrine, if it really applies to the case, Mr. Fergusson would evidently be entitled to claim that the jivst Pyramid in Egypt ought also to be the grandest and best of the whole subsequent line. If it applies, I say; for, while even the Pantheon case (small as it is in the amount of invention or degree of superiority implied, seeing that the Romans had been for ages largely given to introducing stone arches into their buildings, and were at the height of their imperial power and world-drawn wealth when the Pantheon dome was erected, as one only among many other large buildings, so late as about 300 A.D.), is a direct negation that pro- gressive development (usually supposed, even defined, to be supreme within historical. times for all teachable arts) applies in this way to architecture,—still it must be evident to everyone that the gulf is almost infinite which separates that little latter-day invention of a stone dome based on a wedged arch, from the untold pre-eminence of the highest of all stone buildings yet erected, when it was also the first, not only of its own kind, but of every kind of building in stone; and was reared, moreover, in days of the paucity of thehuman race,in a small country, where o soldiers appear among its 24 The Great Pyramid of Egyft. [January, pictured denizens to uphold the oppression of, or insist on obedience to, the mandates ofa tyrant king. This Great Pyramid case is indeed in every way a challenge from primeval time to the whole world since then, past and present, and to every nation that has yet borne empire-rulein the earth, from Nebuchadnezzar’s, of Babylon, to that of the present King William of Prussia. But the one element, however, of height alone, in stone architecture, may form our best and speediest ground of comparison, be- cause height immediately tests the strength of foundations, goodness of material, correctness of work, and steady heads of the builders; while it makes short work, too, of all historical architeCture, for there is nothing left behind by any recorded nation of antiquity that can compete with our modern Christian cathedrals. Therefore let us compare the chief of them in height with the Great Pyramid. Inches. St. Paul’s in London has a peer of 7 "Agee _ ots Peter's at Kome ss . sree Strasburg Cathedral . . J te 8 ORE But the Great Pyramid, either, - . 2 See re) ye) OD, tie. hee tee 5835 Had the Cathedral of Ulm or that of Cologne ever been - finished; according to the plans drawn out for them on paper, they would have been higher than the Great Pyramid; but their architects were unable to finish them, and they are actually very much lower. And again, had the steeple of old St. Paul’s, in London, not been made of wood, it would both have competed for height of stone architecture with the Great Pyramid successfully, and would not have been burned to ashes by lightning in so few years after it was erected: But Cologne Cathedral, I am told rather angrily by Prussians, 7s going to be completed’; for their hero king, anxious to have a grand Roman Catholic Cathedral in the Germany of which he expects presently to be crowned Emperor, and able now at the sword’s point to extract as large requisitions as he pleases from prostrate France, will not stop short of the original design: and then, how will it fare with the Great Pyramid? Will not Cologne Cathedral of the German Fatherland, they ask, then step into the Pyramid’s place as the greatest architectural wonderon earth? Not in any degree, unless it shall also exceed every other building of its own day, by as large a proportionate amount as the Great Pyramid did its contemporaries. 1871.] The Great Pyramid of Egypt. 25 That is, the Prussians, if they wz// enter the competition, must not stop until they have made Cologne Cathedral exceed every other building of the world infinitely, both in height and every other good mechanical quality, and can likewise guarantee that it will be lasting and in sound condi- tion 4000 years after everything that is at present standing has returned to dust or mud. But as it is evident they will never do that, the Great Pyramid remains untouched in its isolation as the most solemn of all architeCtural works; and if, before many more years pass by from the present date of the world, some modern building shall at last be raised to the same, or even a greater height in inches, it will be merely to show all men, and in the most practical and lasting of all the arts and: sciences, that human progressive development in mind and education, combined with national growth in population and wealth, after a painful schooling of full four thousand years, has at last only just succeeded in enabling man, slowly and | with the utmost difficulty, to creepup to again, and touchonce ‘more, that towering height from which he once fell morally ; when refusing to profit by knowledge as it was then commu- nicated to the patriarchs of his race, full, complete at once, and perfect at all points,—he went off on his own founda- tion, and to indulge in his own inventions. 5. The Argument of the Early WooDEN eon There is, indeed, another architeCtural argument occa- sionally resorted to, in order to tone down the almost evidently supra-natural manner in which the Great Pyramid takes its place suddenly and absolutely in the history of man, as thus :— ‘‘The previous architecture may have been of wood, and has therefore perished.” “Well!” we may answer, indulging in our turn for a while in using as history what some term only human fable, “very likely it was of wood:” for not only must all men’s mindsin that early day have been still most notably impressed with the majesty of that gigantic work of naval carpentry, whose dimensions to be were given to Noah by Divine inspiration (and which has never been successfully exceeded since); and of course weaker minds were always showing their admiration by imitating its style, though in ever so distant a degree ;—but the earliest existing stone architeCture of most countries does imitate forms and constructions of pure wood. Nay, indeed, round about the Great Pyramid set there VOL. VIII. (0.S.)—VOL. I. (N.S.) ~~ 26 The Great Pyramd of Egypt. (January, are tombs of the same or closely following ages, where you may still see lime-stone door-posts and ceilings of rock- excavated tombs carved in imitation of palm-tree trunks, while the basalt sarcophagus of the third Pyramid was elaborately chiselled in imitation of a very neat piece of ‘“joiner’s ’ work. Still, however, and even allowing a general wooden archi- tecture to have prevailed amongst all men previous to the date of the Great Pyramid, there is left to the startlingly new-light invention of that building’s unknown architeét, the mighty change, the bzzarre revolution from slight, tough, easily- worked, perishable wood, to the use of hard, brittle, heavy, lasting stone ; and he, too, who made that invention thenand there, made it suddenly, at once and perfeCtly, for there is no trace throughout all the details of that monument of any de- pendence on the previously customary forms when men were working in a totally different material. And yet precisely such a slavery of thought and poverty of invention did pre- vail everywhere else, even into long subsequent ages. Thus the finest Grecian temples may be objected to esthetically for their frequent imitation of soft, pliant forms of vegetable origin in stone material. The earliest Buddhist temples, also, for their circular enclosures of stones cut most expen- sively into the shape of mere wooden posts and rails; while idolatrous Egyptian buildings, at Thebes and Philz, were positively heinous in their persistent use of stone pillars. carved and painted in imitation of the most succulent.and squashy of ail watery reeds. But the Great Pyramid is in this esthetical respect as faultless in its whole as in its parts; for what is not its whole but a reproduction on the grandest scale of the form, true and simple through its whole extent, of a crystal ; or of the very ideal of mineral substance refined and perfected ; the emblem, too, of light, splendour, method, purity, power, eternity ! Again, therefore, a new test, not very scientific perhaps, but brought up by others specially to lower the Great Pyramid, is rather found, on close examination, to leave it with an additional claim to unique distinction. 6. The Lepsius-Wylde *‘ Growing” Tomb Theory. And now I would gladly go on to set before my readers the modern scientific theory of the Great Pyramid and what it rests on, but that with a monument which has looked down on the whole course of known human history, from before Nineveh to besieged Paris, and of which we have 1871.] The Great Pyramd of Egypt. 27 literary notices so old as 2300 years, 7.e., older than of any other still existing building on earth, there are of course many senior theories already in the field, and if any one of these theories explains all the essentials of the case, far be it from me to attempt anything contrary. Nay, indeed, would my readers tolerate it? For their sakes, then, and the subject’s sake, it is neces- sary to examine the sufficiency of at least the best and most popular of these older theories—say the tombic. Egyptologists in general are rather loud—some young men amongst them even intolerant—in insisting on all the Pyramids having been tombs, and having, too, been built for the tombic purpose, and for that alone; while Dr. Lepsius a few years ago published a theory of Pyramid building based on such special view. The real credit of constru¢ting his theory is, indeed, said by some to be rather due to the English archite¢t Wylde, who, with the London painter Bonomi, was hired by Lepsius with Prussian gold to assist in his magnificent peek Expe- dition to Egypt. Which of these eminent men was the chief, or sole, inventor of that theory, I do not pretend to discriminate ; but the fact of its being disputed, sufficiently attests that the theory was thought much of in the Egyptological world, and is therefore worthy of our attention. This Lepsius-Wylde theory, then, shortly is,—that each. Egyptian king of the early time, on his first accession to the throne, immediately began the construction of his future tomb, and in the form of a pyramid. The commencing operation in the first year was to execute a subterranean chamber and sloping entrance passage in the rock, and put a few squared stones, as one layer of masonry, over it. The next year, stones of another layer were added andthe lower one extended; and so on for every successive year of the king’s reign until he died. On which principle the size of . a pyramid always shows the length of the reign of its king. Now this theory may explain the pyramids in general, 1.€., the pyramids subsequent to the Great Pyramid, for many, if not all of them, were undoubtedly. used for sepul- ture, but how does it explain, or apply to, the Great Pyramid ? That pyramid being the greatest of all the pyramids should therefore have been the longest in building, and ought, according to human nature and the general march of things, to exhibit a similar tendency, but in more conspi- cuous degree, to a sort of progressive variation, such as all of 28 The Great Pyramid of Egypt. (January, our more tardily built cathedrals do—begun perhaps in sturdy Norman and ending in flamboyant Gothic. But instead of anything of that kind, behold one, and one only, style both of building and quality. of material reigns throughout the Great Pyramid from top to bottom, and from side to side. The surest, too, of the local traditions colle¢ted by Hero- dotus on the spot 2300 years ago, declare emphatically that the structure was begun from the first as a great building with enormous subterraneans, which occupied the workmen ten years, and a large part of which excavations may still be seen descending into the rock far deeper and further than those of any other pyramid; also that the entire building of the structure was fully prepared for beforehand, and then carried out energetically during only twenty very hard work- ing years, and with well organised bands of workmen relieving each other every three months; and finally, that it was finished by its founder and cased definitely outside when the original finite design was completed, not when he could no longer, on account of death, go on extending it. And what was the design according to the same Hero- dotus,—not, indeed, by any means a perfect authority on all Egyptian matters, but as the ‘‘ father of history,” duly to be noted and commented on? A duplex design. Partly tombic—though he says that that failed, for the king, after all, was mot buried in any part of the Pyramid—and partly mathematical, in a manner too which has been tested by modern scientific mensuration, and found true to within so small a quantity for extensive sub- aérial masonry as two minutes of angle. : Hence, however well the Lepsius-Wylde tombic growing theory applies to other pyramids, it is totally opposed to the manner and history of construction of the Great Pyramid. 7. The Universal Egyptological Tombic Theory. Nothing daunted, however, by that failure, and nothing: interested in the recovery of the old mathematical problem by modern measures, too many of the regular Egyptologists still go on asserting, that the Great Pyramid could never have been intended for anything else than a tomb, because, say they, the preparation of a tomb, or the ‘‘ good house” for a man’s soul to revisit in its future long and thousands-of years-between returns from the other world, was the grand occupation of every Egyptian’s life while in the flesh: the only object, indeed, in whose cause that people cared to ‘‘puild for eternity,” or in so perdurable a manner as the 1871.] The Great Pyramid of Egypt. 29 pyramids; of which it is now an old remark that ‘ every- - thing else fears time, but time fears the pyramids.” Let us come to close quarters, then, with these Egypto- logists, and on their own Egyptological grounds. What they say about Egyptians in general, and their terrific and undying propensities for lasting tombs, is perfectly true; but there are certain turning points in the modern Egypto- logical do¢trine where the pundits thereof are exceedingly hazy, and yet these are the very corners at which clear light is needed to explain the Great Pyramid. Thus, why the form of a square-based pyramid, such as the Egyptian (the subsequent Greek pyramids were triangular based), was first chosen for a tomb, the hierologists do not say a word upon; though they are eloquent enough on the form having been enthusiastically used by the Lower Egyptians for tombs, after its shape had once been invented and practically exemplified amongst them. ‘They also agree that pyramid building for king’s tombs went on only during the early dynasties of the ‘‘ Old Empire ’—the dynasties of the pyramid builders as they are often called—and that it was replaced long before the culminating period in population, power, and wealth of the Egyptian monarchy by a totally different method; viz., by the sub- sequent kings excavating their tombs in the gorges of rocky hills, as in the now well-known valley of the tombs of the kings at Thebes. | , ** Why, then,” I asked recently of a most astute Egypto- logist, “‘why did pyramid building cease so early in the history of ancient Egypt; in fact, before the nation had arrived at its full maturity ?” **Ah!” said the semi-Coptic philosopher, with a deep- drawn sigh, “‘ men began to be frightened at the facility with which the pyramids were broken into, and their contained mummies extracted or destroyed.” A rather clever suggestion was this, but not altogether sufficient; because, although there ave evidences that the pyramids were broken into during days of Egyptian civilisa- tion, still there is no document in existence showing that that violation took place so early as the close of the Pyramid builders’ era. In fact, the suspicion is with many persons that the violence was done a thousand years after- wards ; and, if not by orders of Cambyses, by some of the same Ethiopian fanatics shortly before his period, who also broke open the valley tombs of the kings at Thebes, and robbed them of all their Royal remains just as completely as the Pyramids are found to have been likewise harried. 30 The Great Pyramid of Egypt. [January, Egyptian kings, then, acquired no safer style of burying by abandoning the antique local example of the Great Pyramid; but they gained something else which, as Egyptologists themselves attest, they loved dearly ; for by shaking off the fetters of the Pyramid’s puritan rule,— they at once acquired full license to expand their burial chamber into whole suites of apartments, each one carved, painted, and inscribed more gorgeously than another, both to the glorification of the tomb-maker and the immortali- sation of his idol gods. Even in the age of the Great Pyramid, the tombs of subjects round about it show an inveterate taste for emblazonry and self-glorification to have prevailed amongst all classes of the people; wherefore I put again a most crucial question to the distinguished Egyptologer; as thus— . ‘“ When such self-glorification on the interior walls of the tomb was the besetting idea of all Egyptian peoples in all ages, and was never carried out with more artistic excel- lence than in the very period of the Great Pyramid,—why in that tomb, if it was the tomb, of their king—the very man of all others who could have best paid for any amount of glorification—is there not a particle of such praise of him, neither in sculpture, nor painting, nor writing, on any of the internal finished walls; not even his name on his, in modern times, so-called sarcophagus? No pictures either of the animal gods of Egypt are there; no representa- tion of lands being ploughed, cattle numbered, crops reaped, and the produce brought to the greatest man of the realm, as seen with the non-regal owners of smaller tombs. Nothing but plain geometrical surfaces of exquisite workmanship, and of certain measured lengths, breadths, and angles.” At this question the eminent hierologist became pale, and confessed that he could offer no explanation of the huge and mighty antithesis. There it was, he allowed that, but he could say nothing as to how or why it came there. Neither could he give any exact information as to what precisely those geometrical surfaces in the Pyramid were .or are, in number, weight, and measure; ie hierologist, he said, cared about such things, not having to use them in their science. Lepsius, for example, when encamped with a large party for months together at the Great Pyramid, made not a single measure of the monument, either in line or angle, but spent his and their time in nothing else than copying inscriptions, and pictures in.the neighbouring tombs; nor did Champollion 1871.] The Great Pyramid of Egypt. 31 or Rossellini pay the Great Pyramid’s geometrical qualities any more respect; while Caviglia, even when engaged by Howard Vyse expressly for Great Pyramid investigation, would pertinaciously always go off in any other direction hunting for mummies and “‘ little green idols.” 8. The Mud Foundation Theory. If such, then, be the final and sorry result of all that modern Egyptologists and hierologists can help us to, as to what really constitutes and did originate the Great Pyramid,—who will necessarily blame some sczentists for taking up that primeval monument just at the point where the hierologists have left it; and, after studious toil for years in applying to it instruments for mathematical measure of unwonted precision, think they can now begin to see a connected purpose and clear meaning— consistently, too, with that geometrical key-note gathered by Herodotus—running through all the great building’s dimensions ? No positive blame, perhaps, will be extended openly; but not a few insinuations are indulged in privately, deriding the very idea of so old a building possessing any features on which accurate measure can still be made. Thus, as touching the very first step which would have foube taken in’ such an enquiry, it is asserted in the “Record,” (newspaper) of February 7th, 1868—that no less a personage in modern society than the existing President of the British Association for the Advancement of Science, declared, in a lecture before the British Clergy at Sion Col- lege, that the Great Pyramid, as included amongst “the oldest Pyramids of Memphis,” is founded on alluvial mud ; Poot he declares “ on the site of the great valley.of the Nile ;” and the conclusion is added, that ‘‘ these monuments evidently existed after this great deposit of mud upon which they stand.” Had such a state of things been the case, what sinkings and tiltings of the Great Pyramid’s floors would have taken place through long ages. Would they even have remained to be - measured at all? Would they not rather have gone down altogether out of sight, as the once famous walls of Babylon very speedily did in similar soil ? But, lamentable to say, either for the ‘‘ Record,” if it has reported the lecture wrongly; or for the British Association President, if reported correctly,—there is not a word of truth in the statement. The Great Pyramid is in reality (and I declare it on the strength of nearly four months’ residence at 32 The Great Pyramid of Egypt. [January, its foot) founded ona hill of compact nummulitic lime-stone, at a level of about 100 feet above the alluvial soil of Egypt, and to one side of it. — The building is indeed an admirable example of a pro- verbially surely vock-founded one; for the following can still be made out as the mode of proceeding adopted. The whole of the original rugged top of the hill was cut away and lowered symmetrically until sound rock was everywhere arrived at; and on that firm material, exquisitely levelled, the first of the outer component stones of the Pyramid were laid; every stone being several feet long, broad, and high, but admirably worked by grinding processes, after the ruder cutting, to true mathematical figures; and with their joints cemented, but almost inconceivably fine and close, or no thicker than the vanishing thickness of “‘a@ sheet of silver paper.” While at the four ground corners of the whole structure, shallow, but broad and level-floored sockets were cut in the rock, anciently to receive the lower corner stones of the outside casing; and now, by the accomplished fac, to form the fiducial reference-points for the original length of the four base-sides of the building. ; In conne¢tion with one of these sockets nearly 12 feet square, —said to me one morning at the place, Mr. Inglis, the working engineer for Mr. Aiton—who had, with Arab help, just cleared away all the rubbish and brushed out the last particle of dust from the fair white floor of the ancient work,—‘‘ I have tested the whole of the socket’s floor with my spirit- level, and can find no error in it.” Remarkable testimony, © surely, to come 4000 years after the date of the work’s execution, and upon its being specially examined with ‘instruments of precision” invented in so long after a day. g. The Testing Angle of the Great Pyramid. But how is the whole building—anyone may very properly ask—as to subsidence of foundations or original errors ? The answer cannot be given so positively at present as it may be on a future occasion, because the greater part of every base side of the Great Pyramid is now covered up by huge heaps of loose rubbish. The closest approach, perhaps, yet made, was when I measured the angle of elevation of each of the arris lines of the building with a large altitude- azimuth instrument, the most powerful angular measurer ever taken to the Pyramid: and while, too, this instrument was plumbed accurately over the outer corner of each of the fiducial corner sockets already described, its upper observing signal was a specially prepared staff held at the top of the 1871.] The Great Pyramd of Egypt. 33 Pyramid, where modern breakages are at their smallest limit, by the same Mr. Inglis just mentioned. The result then arrived at, after several hours’ work, was, that the correction to rodned each arris line to the mean of the whole amounted to—on a run, be it remembered, of no less than 700 feet of sub-aérial masonry— Min. Sec. For the Neb parriss lime, = .—. E25 5 N.W. a a) le AG m Si. re eS ER £ ».W. es MP apt Ole A5 While the mean absolute angle was 41° 59’ 45”, which gives for the angle of the middle of any side with the base, ne Se Ir” And as this anal, or something a few seconds only there- from, and which was repeated in every stone anciently forming the flanks of the Great Pyramid, is never attained within a quarter of a degree, and sometimes not within several degrees, by any other Egyptian Pyramid (though there are three which come to within a single minute of each other, so truly could, and did, the builders work when they saw occasion for it), it may be looked on as the characteristic angle of the Great Pyramid, enabling anyone at once to distinguish any of its outer bevelled casing-stones from those of all its neighbours. : Now, in the British Museum, it is stated that there are three casing-stones, presented to the nation by that wr incomparabilis in Pyramidology, the late Colonel Howard Vyse. I rushed, therefore, eagerly, in a passing visit last year, and tried their angles of slope with a pocket clinometer, when, Oh! horror ! one of them gave 48°5°; another, 58°8°; and another, 46°5.. At such angles they sould not have belonged to the Great Pyramid, and it was a serious libel on that exactest of buildings to say so. But these angles, as measured, included, with the angle of level cut by the primeval masons, the angle of level arranged by the officers of the British Museum. Wherefore, in a second attempt, eliminating their recent handiwork by measuring the difference of angle of the bevelled face of any stone from its own next worked surface of a horizontal joint, behold, the angles came out, 52°, 52° 30’, and 51 30’; or, considering the fragmentary state of the stones and the imperfections of my mere pocket clinometer, quite close enough to show that they might all have come from a pyramid of 51° 51’ + x”; and to prove that, the ancient builders must have been at least five times, and VOL. VIII. (0.S.)—VOL. I. (N.S.) F 34 The Great Pyramid of Egypt. (January, probably twenty times, more accurate in their outside masonry than the modern Museum officers have been in their indoor adjustments. Wherefore, then I looked around at the locality to which these precious fragments of earliest intellectual antiquity have been dragged, far from their true place in the world; and for what ? A grand gallery of the British Museum, architeCturally, is the Egyptian; but, as to its contents, almost wholly given over to idolatry. ‘“‘ No, no,” says one apologist, “only to the fine arts.”” Well, then, to that most subtle and truly fine of all the fine arts, ‘“‘ Theotechny ;” for hardly is there a single statue of a cat-headed, or baboon-headed, or unclean dog-headed idol, recovered from any part of idolatrous Egypt or sensual Nubia, but it has had a magnificent pedestal of Aberdeen granite prepared for it, at an expense rarely sanc- tioned by Government for anything scientific, and has then been set up under an imposing light, to be the gazing-stock and cynosure of a supposed admiring and Christian public; while those far earlier works of man, the casing stones of the Great Pyramid, which have no idolatry, nor human theotechny either, about them, but only the perfection of mechanical execution, and the exact embodiment of special angles in geometry and astronomy, in a noble cause and for a purpose recently supposed by some to be in dire@t con- nection with Revelation—they are shoved away contemptuously into an outer passage under a low shelf of a sort of cupboard ; and even there are destroyed in their teaching by atrocious modern blunders in levelling. Knowing the priority of the Great Pyramid to all their other architectural remains (for they have themselves pub- lished it), what a magnificent beginning to their Egyptian gallery,—and with that, to their microcosmal exhibition, of all human architecture—might not the officers of the Museum have made by ere¢ting there, in addition to their fragments of actual Great Pyramid casing-stones— properly levelled,—tfull size models, both ‘of Colonel Howard Vyse’s two complete casing-stones, with their infinitely fine joints and admirable surfaces as he found them there 7 situ, and also of one of the outer corner-stone sockets of the whole building—accompanied by modern levels on a large scale and refined angular instruments to test the position, and exhibit the ancient angles so clearly to all comers that those who ran might read. Then would there have been visible proof before the British public, that the earliest known material remains of intellectual 1871.] The Theory of Irrigation. 35 man are not false gods and animal idols, nor trophies of bloody wars, nor gew-gaw adornments of tyrant kings; but were, on the contrary, works of pure science and unalloyed knowledge, under a peaceful reign where the soldier class does not seem yet to have been invented or required, and the accompaniments are such as neither a modern Christian nor an ancient Job, fleeing from idolatry even in momentary thought, could find any fault with. Yetin place ofthat, seewhat ourcustodiershavedone! Not, however, that the officers of the British Museum, so far as I know, are more idolatrously inclined than other men; but that, being amazingly wise in their own generation, they know perfectly well both what pleases the modern British public, and what also they do not care to be troubled to look at. We have, however, fortunately, to deal here only with that awakened and enlightened se¢tion of Britons which reads the Quarterly Fournal of Science; and then comes the ques- tion—Will zfs members care to hear more about the Great Pyramid, when they now know for certain that it deals only, and under circumstances of peace and purity, with such innocent things as number, weight, and measure, and what may be typified thereby? And will they, in the interests of true history and the primeval condition of man, ever join in representing to Her Majesty’s Government, that if the Egyptian gallery in the British Museum has been built so gloriously at the expense of the nation to do honour to, and illustrate the progress of, the antiquity of intellectual man,—the oldest remains there, viz., those of the Great Pyramid, ought, in simple justice, to occupy the highest and fairest place; while the idols of subsequent times, the fruits of man’s wandering from his first estate into the dangerous and unhallowed mazes of *‘theotechny,” should rather have a lower place assigned to them, if not also a veil of shame drawn over their hideous and repulsive countenances. ___ SL otFe — Ill. ON THE THEORY OF IRRIGATION. By FREDERIC CHARLES DANVERS, A.I.C.E. HE great importance which the subject of irrigation has recently attained to in this country isno doubt primarily due to the forced necessity of utilising our town sewage, and devoting it to profitable purposes, instead of, as has be- come the geheral practice, emptying it into our streams and 36 The Theory of Irrigation. [January, rivers, polluting their waters and destroying their fish. The advisability of adopting a system of irrigation in England has, however, of late years, become a necessity, and one which must annually increase in urgency, entirely irrespective of the subject of sewage utilisation ; and it is only by a proper appreciation of this fa¢ét, and of the causes to which it is due, that we can expect the subject will receive attention. In order to convey the full meaning of the foregoing remarks, it is necessary that we should consider, somewhat in detail, the true theory of irrigation, which will be found, as we proceed, to owe its origin to a disturbance, by the works of man, of the balance originally prescribed by nature between evaporation and precipitation. A careful study of the works of nature, in their primitive state, cannot fail to show the beautiful harmony of creation, and the perfe¢t economy of its arrangements whilst con- tributing only to the support of brute creation. To man, however, in his more elevated sphere, has apparently been given a certain power over the elements, by means of which he can disturb that harmony of existence, which not only is not violated, but is actually promoted by the lower orders of creation. The student of history, by applying this test in his researches into the records of past ages, will find that to man alone may he attributed such a disturbance of the balance of forces as, in progress of time, has led to serious convulsions of nature, affecting not only the geography of the earth, but also many atmospheric and climatic changes in different parts of the world, the occurrence of which there can be no difficulty in establishing. ‘‘ If* we compare the physical condition of certain ancient countries at the present day with the descriptions given by old historians and geo- graphers, of their fertility and general capability of minis- tering to human uses, it will be found that more than one- half of their whole extent—including the provinces most celebrated for the profusion and variety of their spontaneous and their cultivated products, and for the wealth and social advancement of their inhabitants—is either deserted by civilised man and surrendered to hopeless desolation, or at least greatly reduced in both productiveness and popu- lation.” There are two great primary causes which, above all others, may be said to have led to these remarkable changes; and these are, first, the destruction of forests; and, secondly, surface and subsoil drainage. We shall consider briefly these two subjects in the order in which they are mentioned * “Man and Nature,” by George P. Marsh; 1864, p. 3. 1871.] The Theory of Irrigation. wae 7 above, and then proceed to show in what manner their evil effects may best be remedied. It has been stated above that in the absence of human interference the natural law of consumption and supply keeps the forest growth, and the wild animals which live on its products, in a normal state of equilibrium,—and the per- petuity of neither is endangered until man interferes to destroy the balance, and this he does, not wilfully, but in order to contribute to his necessities. Thus, when the means of subsistence began to fail on such ground as had been left open by nature—and which must first have been subjected by man for the supply of his necessities—and as population increased, recourse was necessarily had to the removal of a portion of the forest that stood in the way of further extension of cultivation. A small quantity of wood only being required for fuel and buildings, fire was most probably resorted to in order to clear lands for agriculture, ‘which method, as is well known even at the present day, renders the ground beneath especially suited for vegetation. Such indiscriminate destruction of forests necessarily caused a disturbance in the economy of nature by affecting the tem- perature and humidity of the atmosphere, thus causing con- siderable climatic changes ; by influencing the local distribu- tion of rainfall; and by its effect upon the flow of springs. ‘‘ Forests,” says Becquerel,* “‘actas frigorific causesin three ways :—1I. They shelter the ground against solar irradiation and maintain a greater humidity. 2. They produce a cuta- neous transpiration by the leaves. And—3. They multiply, by the expansion of their branches, the surfaces which are cooled by radiation. As these three causes act with greater or less force, we must, in the study of the climatology of a country, take into account the proportion between the area of the forests and the surface which is bared of trees and covered with herbs and grasses. We should be inclined to believe a priort, according to the foregoing considerations, that the clearing of woods, by raising the temperature and increasing the dryness of the air, ought to react on climate. The observations by Boussingault leave no doubt on this point.” With regard to the influence of forests upon humidity, it must be remarked that the vegetable mould, resulting from the decomposition of leaves and of wood, whilst it helps to obstruct the evaporation from the mineral earth below, absorbs the rains and melted snows that would otherwise rapidly flow away. This moisture it subsequently parts * «¢ Des Climats et de l’Influence qu’ exercent les Sols Boisés et Non-Boisés.” 38 The Theory of Irrigation. (January, with gradually by evaporation and percolation. The water absorbed by the roots of a large tree has been found to be greatly in excess of the weight of that fluid which enters into new combinations resulting in its growth, and the superfluous moisture must somehow be carried off almost as rapidly as it flows into the tree. ‘* Recent experiments* on this subject by Von Pettenkofer were made with an 6ak tree, extending over the whole period of its summer growth. ‘The total amount of evaporation in the year was estimated at 539°16 c.c. of water for the whole area of its leaves. The average amount of rainfall for the same period was only 65 c.c.; and the amount of evapora- tion was thus 8} times more than that of the rainfall.” This evaporation of the juices of the plant, by whatever process effected, takes up atmospheric heat and produces refrigeration, increasing, at the same time, the humidity of the air by pouring out into the atmosphere, in a vaporous form, the water it draws up through its roots. | Although the destruction of forests can hardly be said to influence the total amount of rainfall, it has no doubt, owing to the circumstances above mentioned, no small effect upon its distribution. The most obvious argument in favour of this supposition is that the summer and even the mean temperature of the forest is below that of the open country adjoining. This must reduce the temperature of the atmospheric stratum immediately above it, and, of course, - whenever a saturated current sweeps over it, it must produce precipitation which would fall upon or near it. The manner in which forest destruction has most dire¢tly led to the necessity for irrigation, is, perhaps, the effect which it has upon the flow of springs. ‘The roots of forest trees penetrating far below the superficial soil conduct the water accumulated on its surface to the lower depths to which they reach, and thus serve to drain the superior strata and remove the moisture out of the reach of evaporation. This ensures the permanence and regularity of natural springs, not only within the limits of the wood, but at some distance beyond its borders, and so contributes to the supply of an element essential both to vegetable and animal life. As the forests are destroyed, the springs which flowed from the woods, and, consequently, the greater watercourses fed by them, diminish both in number and in volume. Boussingault, in his “‘ Economie Rurale,” remarks that, ‘“since the clearing of the mountains in many localities, the rivers and the torrents, which seemed to have lost a *« Quarterly Journal of Science,” October, 1870, p. 524. 1871.] The Theory of Irrigation. 39 part of their water, sometimes suddenly swell, and that, occasionally, to a degree which causes great disasters. Besides, after violent storms, springs which had become almost exhausted have been observed to burst out with impetuosity, and soon after todry up again.” Arguing from the basis of facts already established, he draws the conclu- sion that forests have a special value—‘*‘ that of regulating, of economising in a certain sort, the drainage of the rain- water.” To sum up the results consequent upon the clearance of forests, as already set forth, it may briefly be stated that any undue extent of interference with the economy of nature in this respect cannot but be followed by the drying of the vegetable mould on-the surface of the ground affected by the clearance; and it soon becomes removed by the alternate action of wind and rain, leaving behind a sterile soil, possessing none of the properties necessary for cultivation ; but not, fortunately, beyond the power of man to restore, in course of time, to its former powers of reproduction. The means for effecting this are the same which, if adopted earlier, would have prevented its falling into a state of sterility, viz., the artificial application of water to the soil, so as to counteract, in some measure, the consequences necessarily arising from an interference with the proper proportion pre- scribed by nature of forest to open land. Having now considered the effects caused by the destruc- tomer iorests, we have, in the next place, to trace; in a similar manner, the probable evil consequences of land drainage. Surface-drainage is a necessity in all newly-reclaimed lands, and probably dates its origin from the commencement of agriculture; but the construction of subterranean channels for the removal of infiltrated water, marks ages and coun- tries distinguished by a great advance in agricultural theory and practice, a large accumulation of pecuniary capital, and a density of population which creates a ready demand anda high price for all products of ruralindustry. Under-drainage being most advantageous in damp and cool climates, where evaporation is slow, and upon soils where the natural incli- nation cf surface does not promote a very rapid flow of the surface waters, it is not surprising to find that this practice has been carried further, and a more abundant pecuniary return obtained from it, in England than in any other country. By removing water from the surface of the soil, however, the amount of evaporation is necessarily lessened, and the refrigeration which accompanies all evaporation is diminished 40 The Theory of Ivvigation. [January, in proportion. Accordingly it is a fact of experience (as stated by Marsh in his ‘‘Man and Nature” previously referred to) that, other things being equal, dry soils, and the air in contact with them, are perceptibly warmer during the season of vegetation, when evaporation is most rapid, than moist lands with the atmospheric stratum resting upon them. Under-drains, also, like surface-drains, withdraw from local solar a€tion much moisture which would other- wise be vapourised by it, and, at the same time, by drying the soil above them, they increase its effective hygroscopicity, and it consequently absorbs from the atmosphere a greater quantity of water than it did when, for want of under- drainage, the soil was always humid, if not saturated. Under-drains, then, contribute to the dryness as well as to the warmth of the atmosphere, and as dry ground is more readily heated by the rays of the sun than wet, they tend also to raise the mean, and especially the summer, tempera- ture of the soil. Although the immediate improvement of soil and climate, and the increased abundance of the harvests have fully testified to the advantages of surface and subsoil drainage as adopted in England; its extensive application appears to have been attended with some altogether unforeseen and undesirable consequences, very analagous to those resulting from the clearing of the forests. The under-drains carry off very rapidly the water imbibed by the soil from precipitation, and through infiltration from neighbouring springs or other sources of supply. Consequently, in wet seasons, or after heavy rains, a river bordered by artificially drained lands receives in a few hours, from superficial and from subter- ranean conduits, an accession of water which, in the natural state of the earth, would have reached it only in small instalments, after percolating through hidden paths for weeks or even months, and would have furnished perennial and comparatively regular contributions, instead of swelling floods to its channel. By thus substituting swiftly a€ting artificial contrivances for the slow methods by which nature drains the surface and superficial strata of a river basin, the original equilibrium is disturbed; the waters of the heavens are no longer stored up in the earth to be gradually given out again, but are hurried out of man’s domain with wasteful haste; and while the inundations of the river are sudden and disastrous, its current, when the drains have run dry, is reduced to a rivulet. It has thus been shown that a great similarity exists in the consequences arising from the destruction of forests and 1871.] The Theory of Irrigation. AI from land-drainage, both as they affect the temperature and humidity of the atmosphere and soil; which, in their turn are, with a good show of reason, supposed to have a con- siderable effect upon the distribution of rainfall, though not, perhaps, upon the actual amount of it. It is impossible to restore the harmony of nature thus once disturbed, without allowing the lands, cleared and improved, to revert to their original state; but as this would be detrimental rather than conducive to man’s interests, it is more desirable that the balance should be restored in other ways, and by other means, which, whilst counteracting the evil effects above referred to, admit of the retention of the land inits improved state of productiveness. Thus, by the artificial production of moisture in the soil, by means of irrigation, the equilibrium may be restored; whilst the subsoil drainage which has in many cases rendered a resort to irrigation necessary, is in itself essential to the proper development of cultivation by irrigation; otherwise the land, especially in heavy soils, is liable to become waterlogged, to the injury alike of the crops and the health of the neighbourhood. ‘This latter is clearly proved in the case of rice crops, which are so notoriously injurious to health that no European can with safety sleep in their vicinity. ‘‘ Not only does the population decrease where rice is grown,” says Escourron Milliago, “‘ but even the flocks are attacked by typhus.” This is happily not the case where simple irrigation is adopted for the growth of grass, cereals, vegetables, and other crops required in European countries generally, where proper attention is paid to subsoil drainage. The reason why land will not produce good crops in the absence of a sufficient amount of water, even though it be highly manured and otherwise well cultivated, is that moisture is essentially necessary for the admixture with the soil of those invigorating properties existing in manures, which, in the absence of that agency, would, though mechanically mixed with the earth, remain chemically separate and distin from it, and, therefore, not in such a state as to be in any way beneficial for the develop- ment of growth in herbage or plants. With the assistance of water, however, the salts contained in manure are set free and eagerly unite with the soil, by which they may be said to be digested and prepared to become fit food for the nourishment of vegetation; but, even when so taken up, these salts are, during seasons of drought, held from vegeta- tion with an iron grasp by the soil, from which moisture alone can again loosen them. Thus we see that, whilst moisture is required in order to cause a chemical combination VOL. VIII. (0.S.)—VOL. I. (N.S.) G A2 * The Theory of Irrigation. [January, between the constituents of the manure and the soil, it is also further required before that soil will yield up the proper- ties thus obtained for the purposes of vegetation. Having now considered in what manner irrigation. has been rendered a necessary adjunct to cultivation, it remains but to state briefly what steps are required for the con- servancy of rainfall in order to render it most conducive towards a restoration of that balance in nature which previous operations of man have tended so seriously to disturb. These are two; namely, the prevention of waste by storeage, and the construction of channels for the proper distribution of water so collected, properly fitted with mechanical appliances for the regulation of the supply to different fields or districts as it may be required. It is not the object of the present paper to enter into any account of the works or contrivances necessary for the colleétion and distribution of rainfall and drainage water; some brief allusion to what has been done in this respect, in former ages and in other countries, has already been made in the pages of this journal, but a complete study of the history and engineering nature of such works would occupy more space, and deserve more attention, than could be given to the subject in the concluding part of an article which has already occupied so much space; it may, however, be con- sidered of sufficient importance to form the theme fora separate article upon some future occasion. In conclusion, it may be remarked that the question of sewage irrigation is one entirely distinct from that of simple irrigation by means of water alone; the purposes of the one being but the application of moisture to the soil, it in no way supersedes the necessity for manuring, whilst the former combines the application of manure together with irrigation. It does not seem at all probable that the two systems will ever be carried out in conjunction with each other, neither is it necessary that they should be combined. It is also clear that, whereas sewage irrigation is only practicable to a certain limited extent, and in localities bordering upon towns or places where a number of human habitations are congre- gated together, irrigation in its simple form may be adopted, to a greater or less extent, wherever land is brought under cultivation. 1871.] (43) IV. WAK SCIENCE. By H. BADEN PRITCHARD. HE solicitude exhibited just now in all direCtions on the subject of our army and national defences arises, as we all know, from one of those panics induced from time to time by the occurrence of certain stirring events. Periodical alarms of this kind,—causing us with fear and misgivings to pass in review our preparations, and to take stock, as it were, of the wares in which we have been liberally investing our money,—are thus fraught with a great deal of good; we are led thereby to examine minutely into our own system and organisation, and do we but fulfil this task honestly, we learn to profit by the mis- fortunes of others and to accumulate knowledge which otherwise is to be gained only as the result of dearly bought experience. Thus, a wise merchant seeing his neighbour’s business go to ruin, through defective management, will turn a more watchful eye to his own concerns, to assure himself from the occurrence of a similar danger. The subjects of manning our army, of mobilising our reserves, and of devising a simple and trustworthy method of organising our entire forces, have of late much occupied public attention, and been freely discussed in the columns of the press, and so in like manner, perhaps, we may be allowed to turn to that portion of the question in which we afe more neatly interested and consider the extent to which science has been taken advantage of by the military authorities of this country; glancing briefly over those branches of the service where its applications have been the most important, so as to afford the reader some idea of the marked progress effected by its aid in many direCtions. There prevails a wide-spread impression in this country, and more especially, we believe, among scientific men them- selves, that sufficient attention is not paid by the soldier to the many important improvements and discoveries that are -every day made around us whose application to warlike purposes would often be practicable and useful. This idea results, however, simply from entire ignorance of our military system; for, truth to say, there is scarcely any government to be mentioned that pays such strict attention to the advance- ment of military science, whether it be in one department or another, and certainly none other by which investigations in connection with novel warlike materials and methods of warfare are so carefully and completely conducted. As an ‘ 44 War Science. (January, instance of this we may mention the subject of gun-cotton, which has only recently, after many weary years of experi- ment and research, been accepted into the service as a reliable explosive. Austria, it is true, gave the matter some consideration, and contributed, indeed, much towards its further trial and adoption as a military element, but the French and Prussian Governments contented themselves with making a few hasty experiments therewith, and in abandoning the material without the semblance even ofa fair probation; in England, on the contrary, our authorities perceiving the matter to be one of some promise, ordered a thorough and exhaustive investigation to take place, and the consequence is that, after a study of some seven years, a most valuable war agent has been secured, which when employed in torpedoes for harbour defence, as also in mines and other engineering works, is simply without a rival. This, however, only by way of example; and that the reader may form an adequate idea of the great assistance ~ and support which modern warfare really derives from science, we cannot do better than pass in review some of the matters in which it plays an important part in the various branches of the army. It is well known that there exist among our troops two scientific corps, the Royal Artillery and Royal Engineers. The duties of the former body are at once clearly defined, for although the calculations and problems arising in the elaboration of gunnery science are occasionally of an abstruse and profound nature, still they always lie within well marked boundaries. It is different, however, with the Royal Engineers; with them it is no longer one particular science that requires to be mastered, but rather half a dozen, a tolerable acquaintance with almost every applied science being insisted upon in all officers of the corps. For the purpose of imparting this knowledge of the many duties devolving upon the Royal Engineer, a special college has been founded at Chatham, under the name of the School of Military Engineering. At this establishment professors, all of whom are senior officers of the corps, are engaged in the tuition of juniors in mathematics, chemistry, physics, mineralogy, fortification, &c., together with the practical application of such sciences as telegraphy, photography, topography, and other kindred subjects. A course of instruc- tion at this school invariably forms the prelude to an officer’s career, who, although very well educated before obtaining his commission, must furthermore go through this prescribed training. The advantages of this proceeding need scarcely be pointed out, but the striking illustration of the value of an 1871.] War Science. — A5 educated body of men like the Royal Engineers afforded bythe successful Abyssinian campaign—which has been frequently designated a gigantic piece of road-making, and which was in every sense an unqualified triumph over engineering difficulties in a wild and unexplored country, rather than a victory over a half-civilised nation—may be cited as a proof of the wisdom of such policy, if, indeed, any were wanted. During that campaign a wild and unknown country was sur- veyed and accurately mapped out, four hundred miles of road were constructed, a telegraphic system was established, wells were sunk, photographic records were secured, and, moreover, the geological formation of the mountains studied by the engineer officers of the staff entrusted with these multifarious duties. Of course,so much engineering skill is not habitually required in ordinary campaigns, but when this is unneces- sary, other calls of a different nature are made upon the Royal Engineer, whose services are continually required for designing earthworks, stockades, balloon equipments, &c. The improvements and applications of one kind or another in connection with telegraphy, signalling, surveying, and other engineering matters, which are frequently being made at the School of Military Engineering, is a further evidence of the interest taken in science by this intelligent branch of the army, and it is, indeed, not only in the officers, but also in the non-commissioned officers and men, that this superior ability is apparent, many of the latter frequently giving proof of their skill in the elaboration of novelties connected with galvanic batteries, signalling methods; photographic manipu- lations, &c. Turning from Chatham to Woolwich, we find science as well cared for on the banks of the Thames as on the Medway. At the Royal Arsenal, at Woolwich,—the chief source of our military supplies—not only are all the manu- facturing establishments under the charge of men chosen specially from the Royal Artillery and Engineers, by reason of their ability and attainments, but their doings are, more- over, controlled by an experimental committee, appointed solely for the purpose of watching the progress of war science, and investigating such inventions and modifications as are brought to their attention from time totime. At Woolwich there exist three vast factories or departments, occupied respectively with the manufacture of ordnance, ammunition, and military carriages, and the marked progress recently perceptible in all these establishments bears testimony to the desire on every hand to utilise new data and theories con- tributed by competent men. And no better proof of this can 46 . War Science. (January, be shown than by referring to the improvements which have just now been effected in the construction of gun-carriages and slides, an illustration being here afforded of the manner in which necessities are met, and designs carried out in those cases where modifications are urgently called for. It will be remembered that for the past ten years efforts have been continually made by those learned in gunnery to increase to the utmost the weight and calibre of modern ordnance, until at the present moment we possess weapons capable of throwing projectiles weighing as much as five and six hundredweights. In regarding such monster productions the casual observer is so occupied with the grandeur of their proportions and capabilities, that he is apt to overlook alto- gether the question of mounting and working them, for to his mind probably, the whole of the difficulty to be overcome lies simply in the manufacture of the gun. ‘This is, how- ever, a great mistake, for without a suitable carriage and machinery, it would simply be a matter of sheer impossibility to work the gun at all; the difficulty of handling or training amass of metal weighing some five-and-twenty tons, or more,—irrespective of the circumstance of its powerful recoil on firing,—rendering the employment of ordinary appliances useless; this is more particularly the case when such guns are worked on board ship (indeed, these larger cannon are mostly for the navy) and require to be run in and out of the portholes, when, mayhap, the vessel is rolling - and pitching in a heavy sea, and the gun-slides are inclined at a considerable angle. Under these circumstances, it will be easily understood that, unless a ready means were devised for working such heavy guns securely and rapidly in unfavourable weather, their employment in the navy would be altogether impracticable. When these big Woolwich cannon, then, were first designed, a serviceableslide or carriage became an imperative necessity, and the authorities cast about among professional men to obtain a solution of the difficulty. Many plans and propositions were brought forward, and, eventually, Captain R. A. E. Scott, R.N., whose name as a military inventor was already well known, communicated a method of construction which has since proved so efficient and simple that it has been almost universally adopted, and, in truth, there is now hardly a gun in the Royal Navy which is not worked by the aid of that officer’s invention. Without the assistance of diagrams it would be difficult to convey a perfect idea of this clever system, but it may be briefly described as a low frame or gun-carriage, planted upon a long metal slide, so that the 1871.] War Science. - 47 force of recoil being placed exceedingly low, it is the more readily overcome when the gun slides back on being fired. An ingenious tackle arrangement allows of the weapon being readily trained and directed, and a break weighing certainly not more than twenty pounds suffices to check the stupendous mass of metal inany desired position. So easily may a 600-pounder gun be worked by the aid of the Scott gun-carriage, that its loading, running up, and firing, actually requires less time than was formerly necessary in manipulating the old 32-pounder smooth-bore upon a block carriage. Thus, in squally weather, when the gunners actually find it a difficult matter to move about with safety, heavy cannon can be fired in this way at the rate of one round a minute, and, withal, as steadily and truly as if the weight to be handled amounted but to a few pounds. Another invention, of perhaps equal importance, deserves mention while on the subject of gun-carriages. Everyone has heard of the Moncreiff carriage, and the great saving that the same will possibly effect to the country, in the way of rendering unnecessary the construction of fortifications and outworks. The invention represents, in fact, an elaborate mathematical problem successfully solved, the abstruse character of which can scarcely be understood without minute inspection of the details which go to make up the ingenious piece of mechanism. ‘The carriage consists of a platform, supporting upon a movable pivot a strong gun-rest, which may thus be moved easily up and down with a rocking- horse sort of motion, so that the gun is sometimes raised to a height of twelve or fifteen feet, and sometimes lowered almost to the ground; the entire structure is placed in a deep trench or pit dug in the earth—a circular tramway being laid down in the first instance to allow of the carriage 48 War Science. (January, and gun being moved in a half circle so as to sweep the horizon for a considerable -distance—and located so far below the level of the ground that, when ‘‘ run down,” the gun is hidden altogether from view. While in this posi- tion the operation of loading is completed, the machine being afterwards ‘‘run up” by means of a counterweight, which swings the gun aloft until the same is raised some inches above the earth level, when the sighting and laying of the weapon are proceeded with by the aid of a mirror fixed on the forepart of the carriage. On the gun being fired, the recoil is sufficient to send the arm down again under cover, to the loading position, not, however, by a sharp irregular jerk, as might be supposed, but in an exceedingly firm and gentle manner. The advantages of such a system must be ie Sos a ; ae SE TA TIS SQ AN ==: SSS GW SKK ——— SS MMA A wT ZAIN MAM 1 y \ a a ZN Moncrieff Gun-Carriage ‘‘ run up” ready for firing. at once obvious to all; the solid earth itself is made to take the place of the fortifications or parapet, and forms in this way the best protection possible, for, excepting just at the moment of firing, there is positively no portion of the armament capable of being hit or damaged by an enemy. Indeed, so promising has the Moncrieff invention appeared to Government, that a large number of the carriages are already in course of construction, and the possibility has, moreover, been suggested of employing the same in turret vessels with 1871I.] | War Science. 49 low freeboards, where it is of great importance that the weighty armament should be for the most part below the water-line. Had, for instance, the unfortunate Captain been able to lower her guns some ten feet below the sea-level, instead of their being mounted up on deck, there would have been, in all probability, no chance of her heeling over or becoming topheavy in a gale of wind. Whether these par- ticular carriages can, however, be rendered available for the navy remains to be seen, but in any case their value for field works alone is incalculable. We could, if necessary, easily multiply instances of this kind to prove that the manufacturing departments of the Royal Arsenal are fully alive to progress in matters of a warlike nature ; the improvement effected in rifling ordnance, in the construction of cannon, whereby the strain is more equally distributed throughout the metal, in the shape and hardness of iron projectiles, &c., all betoken that in this branch of the War Department much attention is given to the advancement of military knowledge. A more direct proof, however, of the value and reliance placed upon Science by the War Office, is. that offered by the existence of an establishment devoted exclusively to the investigation and elaboration of novel implements of warfare, and to the control of army supplies of every description. ‘This estab- lishment, termed the Chemical Department of the War Office, is in itself a modest and insignificant institution, and appears to the visitor to be almost lost among the busy fac- tories that are crowded together within the limits of the Royal Arsenal. Established some fifteen years ago as a simple chemical laboratory, under the direction of Professor Abel, it has steadily increased .in size and importance, forming at the present momenta general reference department to which all matters bearing upon scientific questions are submitted. ‘The chemical establishment of the War Depart- ment fulfils, indeed, as it now stands, the part of adviser and judge in regard to all supplies necessary for the personnel and matériel branches of the service, and upon the dictum of the chemist alone is the fitness, or otherwise, of army stores decided ; so successfully has this method been cartied out through many years, that the reliance now placed upon the judgment of the gentlemen forming the scientific staff is almost unbounded, and no step of importance is ever taken in these matters without their opinion and sanction being first obtained. To enumerate completely the multifarious duties which constitute the work of the war chemists would require more VOL. VIII. (0.S.)—VOL. I. (N.S.) H 50 | : War Science. | [January, space than we have here at our disposal, but we shall be able, at any rate, to give some idea of the important nature of their labours, and to demonstrate the profit which inevit- ably results therefrom, not only to the nation at large, but to the personnel of the army itself. In the first place, then, we may mention the subject of gunpowder as one of those which has recently received a large share of attention, and which, furthermore, still seems to need very much solicitude. Such a compound as this, whose composition and nature have been known to us through many centuries, should, it might be inferred, have been by this time thoroughly dis- cussed aud ventilated in all the various phases of its behaviour, but, truth to tell, despite what has already been done in the matter, its perfect investigation would seem to have been but just commenced. In the days of the Old Brown Bess, and the times when fire-arms of any kind were considered serviceable weapons as long as they could be discharged without injury to their owners, the manufacture of explosives was studied to a very limited degree indeed ; and beyond the circumstance of paying attention to the con- _ stituent proportions of its elements, no further care was taken in its preparation. At the present moment, however, when we expect our weapons to serve for long ranges, and to perform their functions with truth and accuracy, gun- powder must be looked upon from a very different point of - view. No improvement in its chemical composition has, indeed, recently been made, for truly we use the same pro- portions of sulphur, charcoal, and saltpetre, as at the period when the “ villainous saltpetre” of old was first concocted by our ancestors; but although similarly constituted, the gun- powder of to-day is as different from that used in the days of Cressy as if the two produ¢ts were obtained from totally different sources. The operations of mixing, pressing, and granulating, impart to the material various specific qualities which alter greatly with the manner in which the above manipulations are conducted, and for this reasonitisnot only — necessary for the chemist, in order to ensure supplies of uniform quality, to analyse the product and determine the percentage of its elements, but it is, furthermore, of equal importance to arrive at a knowledge of the hardness, density, and hygroscopic nature of the grains. The question of a gunpowder’s density or compactness (which, by the way, is totally distinct from hardness) exercises, perhaps, the greatest influence upon the burning of a charge, for unless the grains are always manufactured of a uniform character in this respect, results of an equal and reliable nature must not be anticipated. ee 1871.] War Science. 51 The method of testing this particular quality in gunpowder is at once so simple and interesting that we do not hesitate to describe it here in detail ; an instrument, termed a densi- meter, is used for the purpose, consisting of an oval glass bulb, of which the upper end is in connection with an air- pump, while the lower one terminates in a tube dipping into a bowl of mercury. Into this glass globe, which is furnished, we should mention, both at the top and bottom, with stop- cocks, is placed a certain quantity, say 1000 grains, of gun- powder, which fills up, perhaps, one-half or two-thirds of the available space; the vessel is screwed into connection with the air-pump, and the lower stop-cock having been closed, the air is exhausted from the interior of the bulb. When this has been. effected, the upper stop-cock is closed and the lower one opened, upon which the mercury from the reservoir placed underneath rushes into the tube and com- pletely fills up the vacuum, so that nothing is actually con- tained in the glass vessel but powder and quicksilver. In this condition the bulb is disconnected from the air-pump and accurately weighed, and the heavier the result, or, in other words, the more mercury there is present, the denser must be the powder, for the latter, if of a compact nature, takes up but lttle room and leaves a larger space for the mercury ; if, however, the gunpowder under examination happens to be of a light, porous description, the rooo grains of material will of itself have filled up the greater part of the bulb, and the quicksilver in that case has found but limited space therein. Of course, when the weight of a standard powder has been fixed upon, it is a very easy matter to institute a comparison between it and the product under examination, and an accurate result is thus readily obtained. This, then, in a few words, is the method adopted for examining all supplies of powder made in the Government Mills, at Waltham Abbey, or sent in by contractors, for the War Department factory is, by itself, incapable of turning out the large quantity of gunpowder expended annually by our army and navy, even in times of peace. Passing to other questions referred to the Chemical Depart- ment, perhaps the most interesting are those affecting the supply of stores to the army. It forms, in fact, one of the principal duties of the Government chemists to examine rigorously into the nature of all military necessaries, and upon the chemical report alone depends, in great measure, if not altogether, the acceptation, or rejection, of supplies. Thus, contracts for such articles as soap, candles, bees’-wax, oils, paints, tallow, and other necessaries too numerous to 52 War Science. ([January, specify, all pass through the hands of achemist, whocarefully examines specimens of the goods before they are definitely accepted from the contractors. In short, the mode of pur- chasing stores adopted by the war authorities has now been reduced to so perfect a system, that it is simply impossible for dishonest firms to send in defective or inferior goods. The method of proceeding is this: Tenders are, in the first instance, submitted by such persons as may be willing to contract for the various stores, and accompanying the offers made to the War Office are sent samples of the goods firms are willing to supply ; these samples are all tested in the Chemical Department, and the house who offers the most suitable article at the lowest price forthwith gets the contract. As a matter of course, when the goods themselves are sent in, a further critical- examination of them is made sanugere this proves satisfactory, then, but not till then, is the bargain completed and the bills paid. Should the actual supply be inferior to the pattern sent to the War Office in the first instance, the agreement is not only cancelled, but the order is given to the tenderer whose price was the next highest, and the difference in money must then be paid by the house which has failed to fulfil the conditions of its bargain. In this way a very sound method of dealing is established, one that is alike simple in its nature and not easily abused, _ for the Chemical Department, being again responsible to the authorities for the genuine nature of all purchases made through its instrumentality, must necessarily exercise an impartial selection, and perform its functions justly and fearlessly. We cannot obviously describe, in all its particulars, the course pursued by the chemists in examining into .the quality of the various stores coming under their notice, but to afford some idea of the way in which the business is carried on, we will select at random two or three instances to indicate the searching manner in which these trials and tests are applied. The question of candles, for instance, will suit our purpose admirably; here there are many points of a various nature to be considered, such as the time of burning, the photometric power, the melting-point, the dis- position to soften and bend under the influence of heat, and other matters; the most important of all these being, how- ever, the luminosity of the flame. The value of a candle in this respect is estimated by means of a photometer, of which there exist many well-known descriptions, but, nevertheless, we will, at the risk of being tiresome, describe the one just now used at Woolwich for these experimental purposes. 1871.] War Science. 53 The instrument, as our readers will suppose, is fitted ina darkened chamber, and, moreover, screened with black curtains, to shelter it from any stray beams of light ; at one end of a horizontal bar, some three or four feet in length, is planted the standard light with which the candles are to be compared, and which may itself consist of a candle of known luminosity cr of an oil-lamp of uniform light-giving qualities. At the other end of the beam are one or more candlesticks, for the reception of the specimens, fitted upon a stand, which forms, in fact, one side or scale of a balance, the functions of which shall presently be explained. The horizontal beam is marked off into inches or degrees, and acts in the capacity of a tramway, upon which a little waggon bearing the photometer runs freely to and fro when moved by the hand; the essential part of this instrument is a paper disc, of which the centre has been stained with oil so as to appear trans- parent, whenever there happens to be a greater amount of light behind it than before it. This paper disc mounted upon the waggon, separates, as it were, the two flames from each other (that of the standard light and that under examination), and is moved to and fro along the beam, sometimes towards one flame and sometimes towards the other, until a spot is found where the paper diaphragm appears opaque all over and the transparency of the centre is invisible, showing, therefore, that the amount of illumina- tion proceeding from each source is at that point identical. _ This result obtained, the degree marked upon the beam is carefully noted; if the photometer is exactly midway between the two lights, when equal illumination is shown, then we know that the standard and experimental flames are identically alike in intensity; but if, on the contrary, the diaphragm happens to be farther from the standard than the other, then we know that the light under examination is the weaker of the two, for it has been necessary to approach nearer to it to obtain the same amount of illumination as that afforded by the standard at a longer distance off. The degrees marked upon the bar will give the precise result of the investigation, showing at once the comparative power of the experimental flame, and in what respect or degree it is greater or less than the standard; but the photometric test does not end here, for it not unfrequently happens that superior illumination is simply due to an extravagant rate of burning of the material of which the candle is composed ; and a second question thus arises, as to how much of the candle has been consumed during the period of the experi- ment. This is ascertained by the balance arrangement above 54. War Science. (January, referred to, the same being so adjusted that as soon asa certain amount of candle has been consumed, say a hundred grains or so, and the one scale has become lightened to this extent, the heavier scale bears up the lighter one, and, at the same time, a small gong proclaims the termination of the experiment; a stop. clock records at once the exact duration of the trial, and the twofold result—luminosity and time of burning—thus obtained, goes far to establish the actual value of the light examined. The above serves as a good illustration of the nature of the investigations undertaken by the Chemical Department, but the variety of its duties are, as may be supposed, very great. Thus, all water supplies made to barracks and hospitals are analysed periodically as to purity and fitness for domestic purposes, and, in the same way, is a wholesome supply of ration bread ensured to the troops, from con- tractors at the different stations. All the soldier’s requisites, down even to the blacking for his boots and the brass paste for his buttons, are tested, for the purpose of seeing whether they fulfil to the utmost the purposes for which they are required, and the welfare of the troops is in this way narrowly watched wherever at all possible. We see, there- fore, that the existence ofa department of this nature is not only of vital importance to the Government, in checking the quality of the enormous supplies which are made from time to time, but it also stands in the light of a true friend to the soldier, who profits largely by its kindly offices. Indeed, ever since the time the war chemists were first enabled to exercise an efficient control, the complaints of commanding officers, respecting bad stores and bad provisions, have almost entirely ceased, and such questions as a loaf of bread being adulterated with alum, or a ground-sheet being imper- fectly waterproof, are, at the present day, quite unknown. The influence of sound and genuine supplies on the health of troops is, in truth, very great, for if we take, just by way of example, the subject of ground-sheets, to which we have just alluded—an article consisting simply of a stout sheet waterproofed with india-rubber, for stretching upon the bare ground to prevent the damp from penetrating the blankets composing the soldier’s bed when under canvas—the neces- sity of ensuring a perfect and reliable protection is of the greatest importance. Should the thin india-rubber coating be composed of an inferior material, or should the same be but imperfectly attached to the fabric, the ground-sheet would obviously, soon be rendered useless, and the result would certainly be an increase in rheumatism and sickness among 1871.] ' War Science. 5s the troops. It is to make sure, therefore, that manufactured articles of this nature are in no way of a doubtful character, but that they may be relied upon in all climates and under all conditions, that very severe chemical and physical experi- ments have to be carried out, and considerable expense is not unfrequently incurred in the purchase of necessaries as shall be absolutely beyond suspicion. Again, such stores where it is a fact of every day notoriety that adulteration exists to a greater or less extent, as, for instance, in soap, paints, emery, serge, white-lead, &c., special analyses must, in every case, be made; in soap, the amount ane mature. ot the fatty matter has to be considered; in paints, the basis thereof to be ascertained; in emery, the genuine corundum requires to be separated from the mag- netic oxide or other earths usually found in admixture; the serge must be made up entirely of wool, and absolutely free from cotton threads, which in eartridge bags would retain fire and smoulder in the guns, thus igniting subse- quent charges rammed into the piece; white-lead contains as an adulterant a greater or less proportion of sulphate of baryta, and so on with very many other army stores. Beyond. the examination of military supplies, there exist, besides, many other subjects of a scientific nature to be con- sidered by this busy little department at Woolwich. The wants of military men, im regard to new compositions, explosives, applications, and improvements, require to be satisfied as they arise, and these necessarily originate lengthy experimental investigations. The employment of gun- cotton in warfare, which has just been decided upon, shows the care and attention which many of these subjects entail. It is well known that for some time after Schonbein’s discovery of this explosive, all attempts to utilise it in the Same way as gunpowder proved unavailing, and chemists and military men, one and all, found themselves compelled to abandon the task. A fresh impetus was, however, given to the subject some twelve or fifteen years since by an Austrian officer, Captain von Lenk, who, by manufa¢turing the material in the form of twist or yarn, instead of wool, as was formerly the case, and by making certain other minor im- provements, was enabled to produce a material which burned steadily and uniformly, and not with that ungovernable violence which had hitherto characterised its combustion. Despite these valuable modifications, however, the Austrians, in 1863, abandoned altogether what appeared to many a most promising investigation, and the English Government thereupon took up the matter where it had been left by 56 War Science. _ [January, Captain von Lenk. A committee was appointed to work out the question, among whom was Professor Abel, who subsequently made a thoroughly exhaustive study of the subject ; and the interesting discoveries made therewith in the Chemical Department during a period extending over seven years, testify to the skill and ability with which the matter was handled. We have not here opportunity of doing justice to these improvements, which appear so full of value and promise, and must content ourselves, therefore, with merely making this casual mention thereof. For field engineering purposes, for demolishing stockades, for mines, for blasting operations, and especially for torpedoes, the new explosive will be simply invaluable, the destru¢tive effect of gun-cotton being almost without parallel when ignited, or rather detonated, by means of a charge of fulminating powder; while, in other respects, it is, when dry, not more dangerous to store or manipulate than gunpowder, and when wet or damp, not only non-explosive, but actually uninflam- mable, although subsequent drying will restore to it all its valuable qualities intact. The use of gun-cotton, then, whether for military or industrial purposes, is in great measure due to the labours of the scientific staff attached to the War Department, and adds one more weighty proof, were any additional evidence required, of the intrinsic value of scientific aid in military establishments. But we must hasten on. Further mention of the duties which come within the scope of the Chemical Department need not be mentioned, as the reader will by this time have formed some idea of their very extended and multifarious character. As demands for assistance arise, so it is afforded to almost every branch of the service, and, perhaps jan bringing to a close our imperfect sketch of the applications of science in this direction, we cannot do better than describe briefly the principles of a system of electric torpedo defence which has, in truth, only been decided upon within the last month or so. This particular mode of warfare is certainly one of which the value is now placed beyond all doubt, for, when we remember that in the case of the present German war, a hostile fleet of the most formidable character, consisting of some twenty iron-clads and rams, of exceedingly modern construction, has been completely paralysed, or at any rate rendered harmless by the presence of a well-organised defensive system of this kind, it is really difficult to over- rate the importance of such protections. Of course the employment of submarine mines by the Germans in this 1871.] . War Science. | 57 case is, as our readers very well know, by no means the first instance of torpedoes proving of value, for in the Russian War, our own vessels were sometimes considerably embar- rassed by their presence in the Baltic, and, more recently still, the Confederates employed them to good effect against Federal shipping; but certainly no such conclusive argu- ment has yet been advanced in their favour as the circum- stance of the perfect safety enjoyed by the Prussian Ports in the North Sea, in the presence of the overwhelming naval force of the French. As regards our own Government, practical steps to elaborate a good system of defence has only recently been taken, but thanks to the energetic labours _of the Woolwich and Chatham professional authorities, a method of some ingenuity has at last been hit upon, which bids fair to prove both efficient and reliable. It was decided after many experimental trials that choice should be made AA An Ele@ric Torpedo. a. The fuse. 6. The guard. c. The taining insulated plate. Pivot con- of two electric systems, one of which may be termed the electric-closing and the other the ele@tric-breaking arrange- ment. Of these two, the former, or Woolwich system, will probably be selected, it being found by experience that the arrangements for breaking the circuit and the employment of a platinum wire fuse to effect ignition of the charge are open to several objections of a practical nature. The prin- ciples of an electric torpedo are easily explained; a large metal case, somewhat in the form of an Italian oil jar, is rendered buoyant enough to float in mid water, and moored at a Suitable distance below the surface, so as to come into contact VOL. VIII. (0.S.)—VOL. I. (N.S.) ; I 58 War Science. * (January, with any vessel passing over it. ‘These machines are placed in lines or groups in the channel to be defended, and are capable of being exploded either by a sentinel on shore at a particular moment or by concussion against any floating mass or obstruction. Each torpedo contains, or is in com- munication with, a large charge of gunpowder or gun-cotton, and in the centre of this is placed the igniting fuse, an instrument composed of two fine insulated wires, whose poles—imbedded in a very sensitive explosive composition— almost touch one another; an electric current of but slight intensity passing from one of these poles to the other is sufficient to set fire to this composition and thus to explode the charge, rendering necessary, therefore, the employment only of batteries of but small dimensions. An insulated wire leads from the battery on shoretoone pole of the fuse, whilethe other pole is connected with an insulated metal plate located in the head of the machine. We should state that the top of the torpedo has spread over it an iron cage or guard, some- thing in the form of an open umbrella supported on a central pivot, and the former, on being struck by any floating obstruc- tion, swerves bodily round, and for the moment comes into metallic contact with the insulated plate just mentioned, completing in this way the ele¢tric circuit through the fuse ; for the second pole of the latter has thus been placed momentarily in contact with the battery on shore through the medium of the earth, or, more strictly speaking, of the water. An explosive machine of this nature is termed a self- acting torpedo, and will probably be that most suitable for warfare, but a modification of it, also fitted with this electric fuse, will be likewise employed for ignition from the shore. The great advantage of these torpedoes lies in the employ- ment of the Abel fuse just described, which, besides pos- sessing the qualifications of an ordinary electric fuse, allows of acurrent being sent through them at any time to test their efficiency without the slightest risk of explosion, provided, always, the battery employed for the purpose is a comparatively weak one ; signals may also be passed through the fuse in like manner, should the charges happen to be planted midway between two stations, and a torpedo system may thus be used in the absence of other telegraphic communication. Contrived upon this plan we see at once that a system of torpedo defence becomes one of the most effeétive and con- trollable means of harbour protection that can possibly exist; until the actual approach of an enemy the batteries may be kept entirely disconnected from the machines, and the latter 1871.] Spectra of Metallic Compounds. 59 thus preserved in a perfectly harmless condition, so as to be - capable of being taken up and examined, re-distributed, and handled without the semblance of danger. But on the presence of a hostile fleet in the neighbouring waters, in chase, may be, of friendly vessels, it is necessary merely to allow one’s own ships to pass over the line, and when these are safely beyond the boundary, the turn of a switch, or depression of a key, suffices instantly to set up an impassable barrier, and to convert the series of sunken buoys into active submarine volcanoes of the most deadly and destructive nature. V. SPECTRA OF METALLIC COMPOUNDS. of the spectroscope in qualitative analysis has become so general, that it is of great importance to detect and carefully remove any attendant sources of error. Now, there are many other compounds besides those of the alkalies and alkaline earths which afford spe¢tra, and a similarity in the position of their spectral lines and bands causes them to be mistaken on cursory examination for spectra of certain of the alkaline elements. An examination of all the more important metallic compounds, and their faithful mapping, so far as they differed from each other, would eliminate this source of error. Such maps, moreover, would enlarge the field of application of the spectroscope, and enable us to detect the presence of many other bodies than those to which its use is at present restricted. A comparison of these spectra would set at rest many interest- ing points of inquiry and speculation. As, for example, the amount and kind of alteration which takes place in the position, number, and relative intensity of spectrum lines at various temperatures. For the variable influence—the temperature—being but one function of the spectrum, it is by no means to be concluded, without experimental inquiry, that the less and more refrangible parts of speCtra alter pari passu. The fact that at high temperatures decomposition takes place has already led (see memoir of M. Diacon, Ann. de Chim. [4], iv., 5) to a variety of interesting results. He found that in certain cases, when mixtures of volatile com- pounds were examined in the spectroscope, the spectrum obtained was not that of the compounds previously existent 205 5) URING the last few years the constant employment 60 | Spectra of Metallic Compounds. (January, in the mixture, but that of the compounds which had been formed from their decomposition and subsequent re-combina- tion, according to the strength of their affinities at elevated temperatures. For example, a mixture of baryta and calcic © chloride gave not only the spectra proper to these two com- pounds, but that of barytic chloride as well. The careful study of these changes would remove a source of embarrass- ment in spectroscopic analysis. Moreover, it would probably furnish some information upon the chemistry of compounds, which we are wont to study in the solid state or in solution, when converted into vapours, and upon the pee of disassociation. We already possess a very laborious and extensive series of determinations of the spectra of compounds by Prof. A. Mitscherlich (Pogg. Ann., No. 3, 1864, and Phil. Mag: [4], September, 1864). He found that compounds of the first order, in so far as they are volatile and remain unde- composed when adequately heated, always exhibit spectra which differ completely from those of the metals. He obtained the spectra in a variety of ways. Ist. By evaporating solutions in a narrow flame of coal-gas or hydrogen. 2nd. By bringing the substances into the flame of an oxygen-coal-gas burner. 3rd. By bringing them into a hydrogen-chlorine burner. 4th. Evaporating bromine and iodine in hydrogen, and volatilising the substance in the flame produced by the burning of this mixture in air or oxygen. 5th. By passing the gas to be examined either alone, or, incase it is not combustible, along with carbonic oxide or hydrogen, through the middle aperture of an oxy- hydrogen burner, and burning the mixture in air or hydrogen. 6th. By volatilising the substance in a current of hydrogen, and igniting the jet thus charged with the substance for examination. 7th. By passing the electric spark between electrodes of the metals or of their salts when surrounded by an atmosphere of various gases. 8th. By using solutions of metallic salts as electrodes, = passing the spark from liquid to liquid. It will be seen, by a comparison of these methods, that they differ greatly with regard to the temperature at which the spectra are formed. It is much lower when, as in the first method, the solutions of the salts are volatilised than when the fused salts themselves are used. In the latter case, the spectra are much more brilliant and persistent, and the lines are more numerous. The third method was improved by Diacon, in that he surrounded his hydrogen-chlorine burner with a hood in such 1871.] Spectra of Metallic Compounds. 61 a way as to prevent the vapourised substance from coming into contact with the air. He thus obtained the spectra of the chlorides unmixed with the spectra of the corresponding oxides. The feeble illumination in the green part of the spectrum, when hydrogen is burned in chlorine, may fairly be attributed, according to the same interpretation which we apply to the spectra of the metals when burned in chlorine, to the chloride of hydrogen or hydrochloric acid; and the broad bluish-green nebulous band when hydrogen is burned in air or oxygen, to the spectrum of aqueous vapour. The spectra of metals as obtained by Mitscherlich with the electric spark have been re-determined by Huggins and Miller with great care, and the lines obtained have been referred to a scale in which the atmospheric lines form fiducial points. The maps given by Mitscherlich and Diacon, being referred to an arbitrary scale, are intelligible with difficulty. This difficulty applies not only to the position of the lines, but in a still greater degree to their relative intensity and brightness. It was very much to be desired that the benefits of their labours should be made available to us in the present advanced state of spectroscopy, and an attempt was made to reduce their measurements to normal wave-lengths according to Angstrom’s tables. But this was altogether impossible with Diacon’s map, since the intervals had been micrometrically determined, and no comparison has been made with the solar or other standard lines. In Mitscherlich’s maps, the lines a, a, D, E, 0, and F are marked, but when a graphical construction was attempted, by © making the values of these points, as given in the maps, the ordinates, and their corresponding wave-lengths the abscissas, of a curve, the curve was so irregular that the attempt had to be abandoned. Professor A. R. Leeds has instituted some interesting experiments on the spectra of the metallic compounds. He employed the flame of a Bunsen burner, since it is to this source of heat that the speCtra in ordinary laboratory work is referred. The resulting spectra are of two different kinds. In the case of oxygen salts, the spectra of the oxide of the metallic radical is obtained, the lines and bands being more or less broadened and brightened according to the degree of volatility of the salt. With haloid salts, the spectrum proper to the compound and also-the spectrum of the oxide of the metallic radical is obtained. -Two instru- ments were employed in the observations ; one, a single prism 62 Spectra of Metallic Compounds. (January, spectroscope made by Desaga, of Heidelberg: the other a five-prism direct-vision spectroscope made by Hofmann, of Paris. Both were provided with arbitrary photographic scales. ‘The numbers obtained in both cases were reduced to the scale accompanying the coloured drawings of the metallic spectra, by Bunsen and Kirchhoff,* a dash between two numbers indicates a continuity of the spectrum between the points corresponding to them. TABLE OF SPECTRAL LINES AND BANDS. Substance. Position of Lines according to Bunsen and Kirchhoff’s Map. Cuprous oxide.. .. 37°8—44°8 60°8—72"4 78°2 84°1 Cupric chloride with) -... , water “2-2 Lpok 12 Cupric carbonate .. 39°5—43°8—46—47°6 60°5—62°7 67°5—74°6 Cupric acetate... .. 34°6 43°8—46 58 60°5—62°7 67°4 68°9—69°4 70°3—72'2 Cupric sulphate .. 36°6 39°5—46 60°5 67°4 69°83 72°2 81°5 84—84°5 Cupric chloride -. 31°8 37°38 40°2 41°4 45 52 60°8 65°5 68°9—73°6 759 —78'2 81°7 84:1—86°4 887—9QI 92°2 934 94°5 95°7 96°9 98—102°7 105 108°5 I10°8 115°5 1178 I2I°3 127° 127°I 1294 130°6 134°I 1364 1422 144°5 Cupriciodide .. .. 33°6 346 366 39 41 42°I—43°2 45°5—46 627 65 66°5 68°9—69'9 71°83 73°2 75° 76 775 79 813 82°2 83°2 85°I—86°5 89°3—QI 94°2—95°7 98°5— I00 I02—1I03°5 104°8 107°3 Iog‘I—III‘I 1I14°I— I16°I I1g*I—120°6 Plumbic peroxide .. 55°5—58°5 59°5—64°2 66°5—68°4 69°9—71°8 73°6— 76 80°3—83°2 Plumbic carbonate... 39—43°8 46—48°6 53—56°5 58°5—59°5 61°5 63°7 66— 67°9 69°4—70°8 72°7 76 79°3—82°3 841 86°5 Plumbic nitrate .. 34°6 37°6—40°5 41°I—43°8 46—48°I 49°I—49°6 54°5 55°5—5758—59 6o'5—64'2 66°5—67°9 69°9—72°2 746 76°5 79°3—82°7 88°8—9Q1°5 Plumbic chloride .. 35°6—40°5 41°6—42°7—43°8 47—48°I 55—57 58°5 60°5— 63°71 66—66°5—68°4 69°4—71°3. 72°2 72°7 74°. 70°5 77 81°8 82:2 83°2 846 8675 903 92 96°2 Ior 105°8 10876 Manganous chloride 40°2—42°6 47°4—49°8 57--59°4 62—64°3—65°5—66°5 68-9—74°8 75°9—84'I Cadmic nitrate - .. 71°3—72°2 75°5—78 80°3—81'8 88°5—89°8 In the accompanying map of the speCtra of metallic com- pounds the distances on the horizontal divisions of the scale are taken as abscissas, and the relative intensities of the lines and bands as ordinates. It will be seen by comparison of the spectra of the oxygen salts of copper that there is a close similarity between them. Indeed, it is probable that if the drawing had been made directly from the instrument, instead of from notes taken of observations and used in drawing afterwards, the spectra would have been almost identical. The differences would have consisted merely in the breadth and brightness of the lines. But between the * Ka=17'5, Na=50°4, Li'=31°8, Caa=42, CaB=60°8, Std=105. | | THE QUARTERLY JOURNAL oF fo. XXIX,, January, 1871, ee, Nulla yaiatinduatintuihy Coe, «g wilunlnliiyadgatnliatuuin ly Aefe,0,e Niland quutuutiali day cea Waban ea, luna ny ul o£, wnat lutluthalys tnt innit CAML THE QUARTERLY JOURNAL OF SCIENCE. No. XXIX., January, 1871. Sneetra of certain. Vetallie Compounds 10 7 Tt Ww ce, olunlullnlntin ny uuu a7 72 15 Ww 0 7 2 a , & a 6 7. ec, «cog nullity Ht mn until 7) 7 2 3 7 11 61,00 MMIII hy yg uarann 7 Mu 7) 7 2 a 4 Jd CG 8 A 70 a VG eA oa. WOT wiivilii npg iL iy! vt livlunusiveliclirctui mmm hurl wi ul Z 7 2 Go 4 a 8 9 10 u es 15 ws a e cv o, nha tnatuauitighy iin | hg sift Wd, og agg Hin 15 10 nl, inhi yh inl yy lyn ip pin ui 7 a 10 W /2 IS 14 15 1 7 AL yi sucsivelovlivvlvalinicivedealaicividvli wnlinlinalintin) WY Ys woot hy ill | tata mn vi ul LONGNRE-Cof% af ? trey ‘ 4 : a t on JS = ; - . 2 ’ s@ * . - , 4 u - c ‘ - ; & \ . r) 4 ‘ . - ae: . ‘ 3 z r ‘. s _ a ‘ ; . F: . J bes + > 4 - 4 i 4 , ‘ bs oo 7 a" ‘ é yeas : i ; ‘ Woe Fi * fate be a4 - > ‘ F feral Wee 4 x i ; A é 7 ; 4 ’ * 4 “ - » me 2 od 4 . . . 2y 2 2 ' i I es = ' - ye he Rt k “ . 7 = 2 « -* # a . ‘ j ‘ hy 4 1 . % 4 ‘ , A é . = fe te ' , ' . = . { y s rs ae 4 mt > ‘ et = las * 4 . - . F si a 7, 4 a ie bs “ aan ¥ : 7 : ‘ - - io... i . + 1‘) 2 i ‘ ‘ hs . 2 tae 4 ‘ ’ z 4 a. Ia x bs Jeg A Bie Fj z A . f rah , ® a © ea ' Ave 7 . ‘7 - rs - 7 \ = e Bay , H ~ ’ 1 J » é =) they a . f = e ' , é L - : “2 he , » ie le 1 - 4 F 3 ‘ : + yd , iD i r a? - Ca . ei ( ‘ , 1 > Fi ee > ~ a a . as sw Set: ny a ae . ‘ } . t wiry : > a wet ’ 4 © t = > 4 = seege is = nian ty 1871.] Spectra of Metallic Compounds. 63 spectra of the oxygen and haloid salts, and between the haloid salts themselves, the differences are numerous and striking. In addition to the lines in the less refrangible portion of the spectrum, which are common to all, and which belong to the metal as oxide, a great number of lines in the green, blue, indigo, and violet are seen, whose form and grouping are peculiar to the haloid salt under examina- tion. In the spectrum of cupric chloride, the most noticeable feature is the grouping of the lines, in the more refrangible end of the spectrum, into pairs, in which the broader and more conspicuous lines are separated by an interval of about six degrees, while to their right, at a distance of about one degree, another but much feebler line in each case is seen. In the spectrum of cupric iodide no such symmetrical arrangement is evident. With plumbic chloride the same extension of the lines into the upper end of the spe¢trum takes place.. Many of the bands im the spectra of the plumbic salts are beautifully shaded, and commence with a ° feeble illumination on the side toward the less, and increase to a line of maximum brightness on the side toward the more, refrangible end of the spectrum, where they abruptly terminate. Without detailing i in this place what takes place when the various metallic compounds are examined, it will be in- teresting to note briefly the deportment of one of them— cupric chloride. When a mass of this salt, which has not previously been freed from water of crystallisation, is heated on a platinum wire in the flame of a Bunsen burner, it imparts in the first place a greenish illumination to a large portion of the flame. On examining the flame through dark blue glass, it is seen that the part immediately above the heated substance is of a deep blue colour. This becomes tinged with violet, and later a tongue of reddish flame rises in the centre of the blue. If the substance be pushed into the hotter part of the burner, this flame changes to a bright white light, which at its upper edge becomes lurid again. The spectrum in this case is continuous throughout the middle and lower portion, the separate bands of violet still remaining distinct. These phenomena are evidently of a mixed character. When a mass of this salt is carefully heated, so that it is slowly volatilised along with aqueous vapour at the outer edge of the flame, a green band, extending from 60°8 to 72°4, alone makes its appearance. On heating a concentrated solution of cupric chloride, the red lines from 37°8—44°8 appear synchronously with the green from 60°8 to 72°4._ It 64 Various Tints of Autumnal Foliage. [January, | is only at higher temperatures that the great number of lines in the blue and violet make their appearance, and it is not until the salt is fused that the spectrum becomes con- tinuous. In this case the continuity of the spectrum is not attributed to the diffusion of incandescent particles of the solid substance throughout the flame, but to the widening out of the bands in every part of the Spe until their fusion produces white light. We have to express our ‘thanks to the Editors of the ‘Journal of the Franklin Institute” and Professor Leeds for this article. At a future time Professor Leeds hopes to replace this preliminary essay by more carefully prepared drawings, and by a more extended table of the linés referred in position to normal wave-lengths, and in intensity to the solar spectrum taken as a standard. , These further - researches, we trust, will, without delay, be communicated to our readers. VI. ON THE VARIOUS TINTS,;OF AUTUMNAL FOLIAGE. By El. C.) SORBY> FUR{S., &e: aN the following paper I shall endeavour to explain the production of all that variety of colour which imparts such a charm to woodland scenery in autumn. I must, however, frankly admit that very much yet remains to be learned. The complete study of the question would involve very much research, and I see the importance of examining the colouring matters in spring and summer now that it is too late. Still, however, I trust that I shall be able to give a tolerably satisfaCtory general account of the subject, and perhaps little more is desirable on this occasion, since that © may interest many who would not care to occupy their time in studying in detail the optical characters of the colouring matters found in leaves. These are certainly very nu- ~merous, and I have even so far established the existence of about a score, though I have examined only,a few dozen plants with the requisite care. ‘These have, however, been chosen in such a manner as to show the more striking phe- nomena, and probably a more extended examination would merely reveal a greater number of different colours, without materially altering the general results. 1871.] Various Tints of Autumnal Folrage. 65 im the first place; FE must say that it appears very desirable to divide the various colouring matters into different groups or genera, each of which includes a number of distin¢ét substances or species, having some well-marked peculiarity in common. I shall not attempt to give anything like a complete account of the characteristic difference of the various species, since that would involve a long and tedious description of minute particulars, and shall confine my remarks to such prominent fa¢ts as are of importance in the subject more especially before us, and can be described without illustrations or very technical notation. I scarcely need say that such an inquiry could not possibly be carried out by any other than the spectrum method. Chemical analysis would be of very little use, and might easily lead us to conclude that different substances were the same, and the same different. It also is especiaily useful in studying the complicated mixtures with which we have to deal, since particular substances can be easily recognised when it would be quite impossible to obtain them in a separate state. For amore complete description of this method of research I ~ beg to refer to what I have already published on animal and vegetable colouring matters,* and on some technical appli- cations of the spectrum microscope.t I may also say that, spending, as I do, several hours nearly every day amongst the woods, fields, and moors, I have had good opportunity for studying the application of such i inquiries to the subject before us. The group of colouring matters which first of all claims our attention is that which may be distinguished by the term chlorophyll. It has often been treated as if it were one simple substance, but optical examination proves the existence of a number of separate species. ‘The leaves of most plants are coloured green by a mixture of two or more of these. One kind occurs in a state of comparative purity in the small aquatic plants allied to Osczllaria, and the green leaves of trees appear to contain this along with one which gives special absorption-bands. Another is the product of the action of acids on these, and occurs naturally in some leaves, especially when turned brown in autumn, and this gives rise to a very special spe¢trum with numerous bands. A fourth, found in faded Conferva, is closely related to the last, but differs in gradually turning to a deep blue colour, when hydrochloric acid is added to the alcoholic solution. All these have the following peculiarities in common—they * “Proceedings of Royal Society,” vol. xv., p. 433. t+ ‘“‘Quarterly Journal of Microscopical Science,’ New Series, vol. ix., p. 358. VOL. VIII. (O.S.)—VOL. I. (N.S.) K 66 Various Tints of Autumnal Foliage. (January, are insoluble in water, but soluble in alcohol or bisulphide of carbon; the spe¢tra have all a very well-marked ab- sorption-band in the red, but the green more or less com- pletely transmitted, so that the prevailing tint is a more or less modified green. The second class of colouring matters may be described as the xanthophyll group. ‘These are characterised by being in- soluble in water, but soluble in alcohol and in bisulphide of carbon; the spectra show absorption at the blue end, often with more or less well marked narrow bands, but the red, yellow, and yellow-green are freely transmitted, so that the general colour is clear yellow or orange. The different species are distinguished by the character and position of the absorption-bands, which are best seen when the colour ~ is dissolved in bisulphide of carbon. A considerable number are found in various fruits, flowers, and roots, but only two are so commonly met with in leaves as to claim attention in this paper. These appear to be the same as the two which give rise to the difference in the colour of the yellow interior and the orange exterior of some carrots. They may be ob- tained by dissolving in hot alcohol, and agitating the cold solution with excess of bisulphide of carbon, which subsides to the bottom with more or less of the colour, and leaves in the alcohol all other substances soluble in water. Both give spectra with two rather obscure absorption-bands, which lie further from the blue end in the case of colour from the external layer of the carrot, andthe colour of this is orange, and of the other yellow. This latter is the kind most com- monly met with in yellow leaves, from which it may be ob- tained in the manner just described, and when nearly pure it is of the same tint as gamboge. ‘The orange colour is more rare, but occurs in leaves fading to a deeper and more orange-yellow, as, for instance, in those of the India-rubber tree, to which it gives a tint closely corresponding to that of Indian-yellow. It also occurs in a more pure state in the ripe envelope of the fruit of the common winter cherry (Physalis Alkikengt), to which it gives a still more orange- coloured tint, approximating to that of the exterior layer of the carrot. There may be some other colours besides these having bandsin intermediate situations, but, on the whole, Iam disposed to regard them as variable mixtures of the twojust described. Since the name of ervythrophyll has been already applied to the red colour of leaves in autumn, it will be best to adopt it as that of a group containing a number of different species. These may be said to be characterised by 1871.] Various Tints' of Autumnal Foliage. 67 their more or less red colour, which is made more intense by acids, and more purple, blue, or green by alkalies. This is because there is strong absorption in the green part of the spectrum, and the broad bandjis raised towards the blue end by acids, and lowered towards the red by alkalies, which also often increase the absorption at the blue end, so as to make the colour green, though I am much inclined to believe that in most cases this is due to the presence of a second yellow-coloured substance, so that a mere difference in colour is no proof that the red colours differ. Usually, but not invariably, they are soluble in water and aqueous alcohol, but not in bisulphide of carbon. Very many species are met with in fruits, flowers, and roots, distinguished by their spectra, either in their natural state or when acted upon by various reagents, and so far 1 have found at least six in leaves. ‘That which gives rise to the red patches in the beautiful, variegated leaves of some of the geraniums of our gardens, is the same as that met with in the flowers of particular species. The purple colour of the leaves of turnips is the same as that of the purple flowers of the common garden stock. The colour of red cabbage has well- marked peculiarities, and so has that of the root and leaves of the beet. The dark leaves of Tamus communis contain another distinct colour, and so do those of the purple beech, but all these are normal constituents of the young leaves of particular varieties of the plants, and not simply developed towards autumn. Itis, however, impossible to draw a line between the two cases, since the colour which gives rise to the dark brown tint of heath in autumn appears to be the same asthat of the purple beech, and that which occurs in the dark leaves of ivy seems to correspond with the fine deep pink colour developed in many leaves only in autumn, so as to give rise to the splendid red and scarlet, which pro- duce such a fine effect on certain kinds of scenery. In order to obtain these red colouring matters in a satis- factory state for experiment, the leaves should be boiled in alcohol, which dissolves chlorophyll, xanthophyll, and the reds; but, as I have already described in previous papers, the alcoholic solution of most of them rapidly fades, so that the solution is only of a dirty green or yellow tint. On evaporating it to dryness, the splendid red colour chiefly collects round the edges, and the chlorophyll and xanthophyll are deposited more in the centre, so that we can immediately see that there is a mixture. By re- dissolving in water, the chlorophyll and xanthophyll are left insoluble, and theerythrophyll is obtained insolution, andon 68 Various Tints of Autumnal Foliage. [January, gentle evaporation is left in the state of a dry gum, which in ' some cases remains almost unchanged for months or even years. It must, however, be borne in mind that, as thus prepared, the erythrophyll must necessarily \contaummea variable amount of the colours described below, and it is no doubt totheir presence that some of the reactions are due, which both myself and others have referred to the red colour itself. Thus, for instance, when they are slightly oxidised, the broad absorption-band is lowered towards the red end, and, by further oxidation, the colour becomes more or less - orange-yellow, just in the manner that the colour of dark grapes is changed into that of new wine, and this in time to that of very old, as described by me in a paper already cited, but 1 am now inclined to believe that this further oxi- disation, which destroys the main absorption-band, extend- ing over the yellow and green, does really completely destroy the colour of the red substance, and that the more or less orange-yellow is due to the oxidisation of a pale yellow colour previously obscured by the deeper red. ‘This fact is of considerable importance in the subject before us, since it explains why intensely red leaves fade to almost, if not exactly, the same tint as those of the like kind which were previously not at all red; that colour being so completely destroyed as to produce no ‘effect on the tints subsequently developed. The fourth group of colours is composed of those soluble in water and aqueous alcohol, but insoluble in bisulphide of carbon, which have a sufficiently decided gold-yellow colour to justify my distinguishing them by the term chrysophyll group. They vary somewhat in tint from a little more yellow, to a little more red, than yellow ochre. They are made darker and more orange by oxidisation, and thus are in an unoxidised condition as compared with the colours of the next group. In order to prepare them, the leaves should be boiled in alcohol, and after evaporation to dryness at a gentle heat, the soluble portion re-dissolved in water. I have so far met with at least four different species, distinguished by the spectra which they yield on partial oxidisation. The most satisfactory method is to dissolve some of the colour in a small quantity of water, dilute this with alcohol, and then to add a little nitrite of potash and hydrochloric acid. In some cases this gives rise to one or more well-marked absorption-bands, and changes the colour from yellow to pink. In others no bands are developed, but the colour is altered from pale yellow to deep orange-red. On evaporating to dryness, we obtain 1871.] Various Tints of Autumnal Foliage. 69 colours which vary in tint from that of ‘light red” to those of burnt umber and raw sienna. The fifth group of colours consists for the most part of various browns, and therefore I propose to distinguish it by the term phaiophyll group. In most cases they are due to the oxidisation of chrysophyll or other previously-existing soluble compounds, as may be proved artificially. There must be, at all events, several colours of this group, but their accurate determination is difficult, because they do not give well-defined absorption-bands. Onthe whole they may be said to be soluble in water and not in bisulphide of carbon, but in some cases water alone dissolves them very sparingly, and they are more soluble in dilute alcohol, along with an acid. When leaves pass into complete decay they turn dae brown, and ultimately become nearly black. This is evidently due to the formation of dark coloured substances allied to humus, but their accurate determination would be very difficult, and I have not yet studied them very much. Though it may be convenient for our present purpose to separate these more or less black colours from the brighter browns of the phaiophyll group, yet I am by no means convinced that there is any actual distinction between them. They are no doubt produced by the decomposition of most varied compounds, both soluble and insoluble; and since it is perhaps impossible to obtain these in a pure state, it is difficult to ascertain the exact connection between the various unaltered and altered produis. Having given a general account of the various colouring matters met with in foliage, I will now proceed to show how they serve to give rise to the almost endless variety of autumnal tints. These are usually due to varying mixtures of colours belonging to two or more groups. It is very doubtful if any leaves are coloured by one single substance, and generally they contain not only colours belonging to several groups, but even more than one of the same group. Unfaded green is are coloured mainly by chlorophyll, but the tint is very much modified by xanthophyll, and by colours of the chrysophyll group. ‘The presence of these, in varying relative and absolute amount, explains in a most satisfactory manner all’ the various brighter and darker greens met with in different leaves in different conditions. It is doubtful if chlorophyll has ever been seen free from xanthophyll. On heating green leaves with alcohol, a bright green solution is obtained. On agitating with bisulphide of 70 Various Tints of Autumnal Foliage. [January, carbon, this sinks to the bottom with the greater part of the chlorophyll and some xanthophyll in solution, whilst the alcohol retains most of the xanthophyll and some chloro- phyll. After agitating this with a little fresh bisulphide, evaporating to dryness, and dissolving out the chrysophyll by water, when dry, the impure xanthophyll may be dissolved in bisulphide of carbon. ‘The solution of chlorophyll in the bisulphide first obtained may be somewhat purified by agitating with fresh alcohol, but even then the spectrum clearly shows the absorption-bands due to xanthophyll. Still, on comparing the two different products, we can see at once that an approximate separation has been effected, and that for an equal amount of chlorophyll one contains six or eight times as much xanthophyll. This is a mere green- yellow, and the other a bright green; but, since it must be made considerably brighter by the xanthophyll, pure chloro- phyll is no doubt of a darker and bluer green colour. The tint of many green leaves is also much modified by various colours of the erythrophyll group, which give rise to more or less green browns, and in some cases almost to black; for the green chlorophyll absorbs the blue and red rays, and the erythrophyil the- green, so that all light is extinguished. If the erythrophyll preponderates over the chlorophyll, we have a red or even purple green, as in the case of the copper and purple beech; and thus, independent of any change, there is a considerable variation in the tints of normal growing leaves. It is, however, in autumn, when the chlorophyll has disappeared, that the brighter and more definite colours are produced. The amount of xanthophyll which is found in green leaves is so considerable, that probably the yellow colour of faded leaves is quite as much, or even more, due to that which previously existed than to any specially developed in the change, and the alteration may be said to consist chiefly in the disappearance of the chlorophyll. The result of this is that a deep green is changed into a bright yellow, and the general change in the spectrum is that there is no longer any absorption at the red end. Probably, how- ever, few yellow leaves are coloured merely by xanthophyll, and the tint of many depends quite as much on the chryso- phyll, and is also very much modified by colours of the erythrophyll and phaiophyll groups. As I have already named, many leaves contain colour of the erythrophyll group, even when young and healthy, but the production of a red colour is more common in autumn, when their vitality is diminished. In some cases it takes place whilst the chlorophyll is unchanged, or only partially 1871.] Various Tints of Autumnal Foliage. 7B: altered into the browner modification, and then its produc- tion merely gives rise toa dark brown which does not attract the eye. The deep brown colour of heath in autumn is an example of this, and on careful examination it may be seen that the brown shade is almost entirely confined to the side of the plant which is exposed to strong light. The red colouring matter is so disguised by the green chlorophyll that one would scarcely expect to extract, by the method already described, a colour quite equal in beauty to carmine, and of almost exactly the same tint. Very many other illustrations might be given of the same general fact, but the colour does not attra¢t attention until the chlorophyll fades, and then the mixture of the previously existing red with a more or less pure yellow gives rise to scarlet. This may be seen to great advantage in the leaves of the common bramble and many other plants. It may then be asked why We never see a fine scarlet in the case of heath or purple beech. The explanation seems to be that in them the red colour is not the same as in the case of the numerous plants which turn scarlet, and is so much more easily decomposed that it entirely fades before the chlorophyll is altered. The spectrum method indicates that the colour of these two plants is the same, but differs from that red colour which occurs in most of those turning to a fine scarlet, as, for example, in the leaves of the bilberry, bramble, hawthorn, Berberis, cherry, apple, and guelder-rose. In other plants the red colour is not specially developed, whilst the chlorophyll is unchanged, but is produced at the time of that change, as if in some way dependent on the same cause. I have especially studied this point in the case of the leaves of the common sorrel, and find that the production of the red colour depends in some way on exposure to light, and on loss of perfect vitality. I had long known that most of the bright red leaves met with in the fields were those which had been broken off from the plant, and yet when dried in the house, or even kept in the dark with their stalks in water, the green leaves fade to dull yellow. I therefore placed in my garden detached leaves with their stalks in the earth, some with the upper, and some with the lower surfaces exposed to the light, some in the sun, and some in the shade, and I found that those which turned to a fine red were those exposed to the sun with the lower surface upwards. I have also noticed that the red colour is often produced in spots where the leaf has been injured by insects; and in the case of other plants I have remarked that the leaves on partially broken twigs show this colour to unusual advantage. I am V2, Various Tints of Autumnal Foliage. [January, therefore disposed to attribute the formation of the red colouring matter to some change which takes place when the leaves are not actually dead, but in a state of very low vitality. Of course this is scarcely applicable to those in which a red colour isa normal constituent ; but, at the same time, even then it may indicate more or less of the same kind of condition ; for I have remarked that in those branches of the bilberry which are of a fine scarlet in the early part of the year, the form of the leaves departs considerably from the usual type, as if they were not altogether in a healthy state. Perhaps the fading of green leaves to yellow, and the normally yellow state of some leaves may be referred to a somewhat similar low vitality, which either permits the chlorophyll to become changed or prevents its formation, as in the case of plants growing in the dark. I may here say that there seems every reason to conclude that on further change the red colour so completely fades away as to produce little or no effect on the general tint, since faded red leaves cannot be distinguished from those of the same kind which were not red, and the artificial. oxidisation with nitrite of potash, of the substances soluble in water, extracted from scarlet leaves of the bilberry, gives rise to exactly tmemsamie colour as in the case of the yellow or green leaves. I may also here say that when scarlet leaves are digested in hot water the red colour is easily removed, and the green, yellow, or brown colours left as the case may be. | In studying the further changes. which occur in leaves in autumn, it is most important to understand the properties of the various colours allied to the chrysophyli group, since it is to them that we must attribute a great part of the more prevailing tints. Onthe whole, clean scarlets are uncommon in this country in the case of large trees, and simple bright yellows are not very abundant, or only last for a short time; since the chlorophyll seldom disappears entirely before the chrysophyll is more or less changed. Much remains to be learned with respect to the various kinds of chrysophyll, and the connection between each and the species or special variety of the plant, and the circumstances in which it is placed. As far as my present knowledge enables me to judge, there is some decided connection between the kind of colour and the species of tree, but, at the same time, I have met with entirely different colours in the same species growing in other situations, and I am even disposed to think that there may be individual: differences, analogous to what is so common in the colour of the hairof animals. It is this complication of facts which makes it very difficult to explain 1871.] Various Tints of Autumnal Foliage. 73 the cause of some of the results, but, at the same time, this variation is in complete agreement with the varied tints of different trees of some species. One of the most striking kinds of chrysophyll which has much influence on autumnal tints is that contained in yellow beech leaves. It is of pale yellow colour, but when dissolved in alcohol and oxidised by means of nitrate of potash and hydrochloric acid, it is changed to deep pink-red. When dissolved in water the oxidisation gives rise to a very copious precipitate of the same colour, which is, therefore, apparently only imperfectly soluble in water, but more easily in acid alcohol. ‘This kind of chrysophyll appears not to be formed till the time when the leaves begin to turn yellow, since I found that green beech leaves contained much of another, which is often associated with the one just described in other trees. The yellow leaves contain the yellow xanthophyll, whereas the orange-brown leaves contain the orange modifi- cation, as though, perhaps, derived from the other by partial oxidisation. I have met with this kind of chrysophyll in the leaves of the bilberry, and in some varieties of plane, and in a less: pure state in many others. Another species of chrysophyll found in many leaves may be procured from some varieties of the common elm. I have found that leaves of large size and loose texture give it in the most pure state, but in some it is mixed with much of the kind found in the beech, and in others is almost entirely replaced by a third colour, which is but little altered by nitrite of potash. The colour to which I wish, however, to call especial attention turns to a pink-orange when thus oxidised, and gives a spectrum with a sufficiently well-marked narrow absorption- band, in the centre of the green, and a fainter nearer to the blue; but after a while these bands fade, and the colour becomes orange-yellow. I have met with this colour in the leaves of the poplar, Spanish chesnut, alder, apple, and oak; and, as far as I am able to judge, there are very many trees whose leaves contain variable mixtures of this with that found in yellow beech. I have met with a very special kind of chrysophyll in the leaves of a plane tree, which turns to a very fine yellow. This gives, on oxidisation by nitrite of potash, a pink colour, with a yery well-marked absorption-band in the green, nearer to the red end than in the case of that met with in the elm. Inthe green leaves of other planes of the same species I found only that colour so common in yellow beech leaves, and I have noticed that such plane leaves do not turn yellow, but to an orange-brown, modified by the VOL. VIII. (0.S.)—VOL. I. (N.S.) L 74. Various Tints of Autumnal Folioge. [January, continued presence of chlorophyll, though, when this has been dissolved away by means of alcohol, the former colour can be very clearly seen. It is very probable that other kinds of chrysophyll will be found on more extended examination, and that a more complete knowledge of their properties will serve to explain many facts which are still obscure. I have, indeed, even now good reason for believing in the existence of some others, but their characters do not differ sufficiently from those described to materially modify the general results. The alcoholic solutions of all these various kinds of chrysophyll resemble one ancther in being changed by oxidisation with nitrate of potash and hydrochloric acid to pink-red substances, which alter more or less slowly into orange colours. When thus changed, and kept dry, or in solution with a slight excess of ammonia, they are further modified into various brown substances. This is well seen in the case of the red colour obtained from beech leaves, which, on the addition of ammonia, shows a well-marked absorption-band in the orange. This slowly disappears, and, after keeping for awhile, when evaporated to dryness, it is nearly as brown as burnt umber, and the addition of hydrochloric acid to the solution dees not restore it to the original fine pink-red, but we have a decided brown colour, to some extent absorbing the red end of the speCtrum, which was previously quite clear. All these modified colours, when dissolved in sulphuric acid diluted with an equal bulk of water, and still further oxidised by means of chlorate of potash, merely fade, and are thus in that state of oxidisation which is characterised by a maximum depth of colour. These different changes may be simply due to an alteration of the chrysophyll, but, at the same time, there are cases which seem to indicate that almost, or quite, colourless compounds may contribute to the produ¢tion of deep colours. For example, when the fresh leaves of Acuba japonica are digested in cold alcohol, the solution evaporated to dryness and treated with water, a clear yellow solution is obtained, which, when evaporated at a gentle heat, turns dark brown, on account of the formation of an insoluble substance of that tint. Water then extracts the apparently unaltered yellow substance; and, though these facts are an exception to the general rule, they seem to show that a dark colour may be formed independent of the previous existence of a colouring matter of the chrysophyll group. Though some of the various phaiophyll colours are soluble in water, the proper solvent to extract them from the 1871.] Various Tints of Autumnal Foliage. 75 leaves is moderately strong alcohol, to which a few drops of hydrochloric acid have been added. Since they are almost insoluble in hot neutral alcohol, it is well to digest the leaves first in it, to remove some of the xanthophyll, and any other colour soluble in the liquid. After evaporating to dryness the solution in hot acid alcohol, any colour soluble in water should be dissolved out, and the insoluble portion digested in a cold mixture of alcohol and water, in equal parts, with a little hydrochloric acid, which dissolves much of the phaiophyll, and leaves an impure xanthophyll. After evaporating the clear solution to dryness, strong neutral spirit dissolves the more pure colour, which is always darker and browner when dry than when in solution. As thus obtained, it may be, and often is, a mixture of various coloured substances, and it is only by comparing those from different specimens of leaves that we can arrive at a satis- factory conclusion respecting them. For example, beech trees are occasionally found whose leaves turn in autumn to a very deep colour, almost exactly like burnt sienna. These yield a fine red phaiophyll colour, which, when dry, is redder than burnt sienna, and almost exactly like so-called ‘“‘light-red.”” When dissolved in alcohol it is of a fine pink- red colour, and corresponds in every particular with that obtained by oxidising the chrysophyll of yellow beech leaves as described above. The leaves of other beech trees turn to an orange-colour, like burnt sienna mixed with raw sienna, and these yield what appears to be a mixture of the above red colour with the browner modification into which the red passes, as already explained; and those leaves which have remained some time on damp ground contain still less of the red and more of the brown, which, when approximately pure, has a tint like that of a mixture of burnt sienna with burnt umber. Besides these, neutral alcohol or water extracts from the leaves a colour which closely corresponds with the orange modification already mentioned ; and thus it will be seen that the actual tint of the leaves is the result of a mixture sometimes of at least six different colouring matters. I have not been able to obtain from the leaves of the elm, chesnut, poplar, or oak, any pink-red colour corresponding to that first formed when the chrysophyll is artificially oxidised, but only the brown modification of burnt umber tint which corresponds almost exactly with what is formed on keeping the artificially oxidised in a dry state. This absence of the redder colour appears to be because it passes into the brown modification much more rapidly than the analogous colour in beech leaves, so that whilst they remain 76 Various Tints of Autumnal Foliage. [January, comparatively unaltered for weeks, those of the other trees just named often turn from light yellow to brown in the course of a day or two. The correspondence between the artificial and natural colours in these various cases is ex- tremely close; and though the tint of many leaves is very much modified by the presence of other colours, yet I trust that the examples I have described will sufficiently well illustrate the fact that the most characteristic brown or orange shades are mainly due to the various kinds of phaiophyN, derived from the oxidisation of previously existing soluble compounds more or less characteristic of particular species or varieties of trees. The two principal kinds are those seen to advantage in the beech and in the Spanish chesnut or elm, but it seems as if they very commonly occurred mixed in very variable proportion, not only in different sorts of trees but in different leaves of the same, so as to give rise to every shade of redder or yellower brown, made more or less dull by the presence of more or less of the dark humus. Another very important modification of the tints is that dependent on the continued presence of chlorophyll, after the chrysophyll has been completely altered. This entirely prevents the development of any brilliant tints, since it makes what would otherwise be a ‘fine orange-brown merely a dull brown-green, like that commonly met with in the faded leaves of the alder. In such cases, the chlorophyll is sometimes found to have been completely changed into the dull green modification produced by the action of acids on the brighter green kind. I need scarcely say that many leaves are variably and sometimes very curiously mottled, on account of the changes I have described having occurred partially and in patches. There seems to be a connection between some of these facts and the conditions under which the trees grow, and we cannot there- fore be surprised that differences in climate, and variations in the weather of particular years, very materially modify the character of the prevailing tints. On this account, perhaps, some of the illustrations I have chosen may not be appropriate in all cases, being chiefly derived from the district with which I am most familiar. The following table will serve to show the general relation of the various groups of colouring matters, their prevailing tint when alone, and the varying shades which result from the mixture of varying quantities of any of the two con- nected by brackets. I have also inserted on the left hand side the condition of the leaves of which, on the whole, the colours ‘may be considered characteristic, commencing with 1871.] Relations between Chemical Change, Ge. 77 perfect vitality, when carbonic acid is decomposed and oxygen set free, and ending with death and decomposition when the opposite change occurs. Complete vitality | Chrysophyll (gold-yellow) | More or less bright green. and growth .. | Chlorophyll (deep green) More or less green-brown. Low vitality and acne (crimson-red) change .. .. | Xanthophyll (bright al | More Gy Nese WEES More or less bright orange- brown. Death and decom- { Phaiophyll (brown-orange) | Less picate abate heawe position .. .. { Humus (brown-black) According to these principles, we must look upon the pro- duction of the fine tints of autumn as evidence of the diminished vital powers of the plants. I presume that this can admit of no-doubt, and it agrees with the faét of unhealthy branches of a tree turning yellow whilst the rest remain green. The subsequent development of more sombre tints is evidence of more complete death. Perhaps some of my readers may think that such an explanation robs the fading leaves of autumn of much of their poetry, but, at the same time, I trust that the facts I have described may tend to explain many of the beautiful and varied tints which delight us so much in autumn, and that a knowledge of such general laws will compensate for any loss of poetic sentiment. VII. ON THE RELATIONS BETWEEN CHEMICAL CHANGE, HEAT, AND FORCE, WITH A SPECIAL VIEW TO THE ECONOMY OF ELECTRO- DYNAMIC ENGINES. By the Rev. H. Hicuton, M.AS§late Principal of Cheltenham College, and Fellow of Queen’s College, Oxford. CHAPTER I. ew if THINK I may say, first, that the theory at present alr generally accepted, and which it would be considered somewhat heretical to deny, is this; that a certain amount of chemical change corresponds, and is interchange- able with a certain amount of heat and electric force; and that this heat again corresponds and is interchangeable with acertain amount of work or mechanical energy. ‘This is, no doubt, a very pretty, plausible, and apparently philosophical theory ; but, is it true? or, how farisit true? ‘This is the question I now propose to consider, with a special view to 78 . Relations between Chemical Change, [January, the further question of the economy of electro-dynamic engines. Let us first examine the first part of the theory—namely, that a definite amount of chemical change is interchangeable with a definite amount of heat and of electric force. I think we may safely grant that the doctrine of the equivalence of definite amounts of chemical change, heat, and electric force, is true when the chemical change takes place under precisely the same circumstances. This may be true; but it is a truth practically useless. 2. But does a definite amount of chemical change correspond with the same definite amount of produétion of heat and electric force under different circumstances, say of atmospheric pressure, surrounding temperature, contiguity of different substances, and other external influences ? There may, or may not, be a priovi reasons why it should, and such have been urged as conclusive reasons derived from the axiom of conservation of energy; but I think I shall show that there are practical reasons for doubting the universal applicability of this principle except in mere mechanics. 3. But, before doing so, let me quote an instance which shows the great practical importance of the question. Take the case of the production of iron by the hot and cold blast. With the cold blast certain quantities of ore, flux, and fuel are mixed together; combustion is induced, cold air passed through the mixture, and the various chemical com- positions and decompositions take place. With the hot blast, part of the fuel is used first to heat the air which passes through the furnace, and part is placed as before in the furnace. It is found that in this way a much greater effect is produced by a smaller quantity of fuel. This, of course, does not prove that more total heat is thus produced, but it shows that it is produced in a more effective manner. 4. Now let us take the case of the production of heat in a galvanic battery. The theory at present generally accepted is this :— (1). That the total amount of heat produced in a circuit depends upon the amount of zinc or other metal oxidised, though the distribution of the heat in this circuit depends upon the resistance of the several parts ; being directly pro- portioned to this resistance. Thus, if H be the amount of heat and ~M the units of weight of the metal consumed, HanM. And if I be the quantity of eleCtricity circulating in each section of the circuit and 7,, 7,, the resistance of two 1871.] Heat, and Force. 79 different portions of the circuit, the heat produced in each of these portions in a unit of time, H, and H,, willbe Ek =I 7, Py (2). If R be the total resistance of the circuit, and H the total heat ina unit of time, Hal?R. Now if these equations be true, they must be consistent with each other; if incon- sistent with each other, one or all must be untrue. In order to show that Iam not mis-stating the theory, let me quote from an able article in Watts’s ‘‘ Dictionary of Chemistry.” “‘The development of heat in liquids by the electric current is regulated by the same law as in metals, the quantity of heat evolved in a given time being proportional to the resistance of the liquid and to the square of the strength of maememirent (ff. Becquerel, Ann: Ch. et Phys., [3], 1x., 21). Moreover, Joule has shown (Phil. Mag., [3], xix., 210), that the evolution of heat in each couple of the voltaic battery is subject to the same law, which, therefore, holds good in every part of the circuit, and, therefore, also for the entire circuit, including the battery.” “With a current of given strength the sum of the quantities of heat evolved in the battery, and in the metallic circuit joining its poles is constant, the heat actually developed in the one part or the other varying according to the thickness of the metallic conductor ; this was first shown by De la Rive, and has been confirmed by Favre (Ann. Ch. ays, (3), Xl., 393).” Let us now test these laws and see when they are consistent with each other and when inconsistent. 5. We know that I, or the quantity of electricity circulating in each section of a battery circuit in a given ni : apa being the electro-motive force of the metals used, x the number of similar cells in the battery, Rd the resistance of each cell, and vw the resistance of the rest of the circuit. Take a battery of this kind and we shall find the total heat evolved in it in a given time will be H=(—2* _)' x (@Rb-+10) nkb+rw aS m2 nkRb+rw Now double the resistance in each cell, by using plates of half the size, or in any other manner, and double the resistance of the wire ; then we get— time, is expressed as follows:—I= 80 Relation between Chemical Change, (January, nit ~ a(nRd +7w) Or the circulating quantity of electricity is half what it was, and consequently only half the metal is consumed, but as H=I?R, this equation will now become— E 2 a= ——s Rb: 2(nRb+rw Gabi al ge oa 2(nkb+7rw) That is, the quantity of heat is now half what it was, and only half the metal is consumed. In this case the theory is consistent with itself. ' 6. Let us take one more case in which it is so. Double the number of cells and double the resistance in the con- ducting wire; then— bs AT eB a iS) a(nRb+7rw) nRbd+rw but now H becomes— ; ; 2 22 eae AERA r) pe nRb+rws nRb+rw or double what it was before; that is to say, we have doubled the circulating electricity, and consequently the consumption of zinc, and also doubled the heat. Here then, again, the theory is consistent with itself, and Wwe may accept it as partially true when the circumstances do not vary more than in the manner we have described. That is to say, 7” some cases the theory is partially true, and it will be found that the general theory itself has been erroneously deduced from an experimental examination of such particular cases. I say partially true, because we have as yet spoken only of the total heat produced, but not of its distribution in the various parts of the circuit. Further on I think it will appear that the laws which are supposed to regulate this distribution are not true, except in particular cases. 7. But now let us vary the circumstances in another manner. | Take a galvanic couple of (say) zinc and platinum, having an ele¢tro-motive force, E, a battery resistance, Rd, and a conducting wire with a resistance, 7w. ‘Then,as before— Bye E? H=PR= )(Rb-+7e) = (aes COLES yaaa Next, instead of the single galvanic couple of zinc and 1871.] Heat, and Force. 81 platinum, take two couples of zinc and (say) copper or other metal having an electro-motive a ; take the plates of such a size that the battery resistance of the two couples together shall be exactly equal to the battery- resistance of the former single couple, and use the same conducting wire; then the quantity of electricity circulating is exactly the same as before, and H becomes— (2) E? That is, the heat and circulating eleCtricity are exactly the same as before, and yet as there are two couples instead of one, and the circulating electricity is the same, exactly double the amount of zinc is consumed. The theory, then, is here inconsistent with itself. If the zinc consumed be doubled, the heat produced should be double, and the amount of electricity circulating in the circuit should be double: Half the zinc, therefore, is wasted, and the oxidation of a given weight has either pro- duced only half the heat, orif it has produced an equal amount of heat, only half of it has been put into circulation ; and if the magnetical and dynamical effects be proportional to the heat circulating, or to the electricity circulating, or to any power of these, we get from the same quantity of zinc only half of the effect which we got in the first case. It is evident, again, that by taking a single couple of zinc and of some other metal whose eleétro-motive power is half of E (that of zinc and platinum), and halving the total resistance of the circuit, we should get the same quantity of electricity circulating, and an equal quantity of zinc con- sumed as in the first circuit, but only half of the heat R 2” R being the resistance of the original circuit. So that we can construct different batteries in which respectively the ratio of the zinc consumed to the heat produced shall be the same or shall vary in any proportion. 8. Now take another instance of the same kind. First take as before a single pair of zinc and platinum. Then we get the same equations and results as before; namely— H=_ Rbd+7rw Next, insert in the circuit a cell with two plates of zinc, VOL. VIII. (0.S.)—VOL. I. (N.S.) M developed ; for the equation would now become H=[? 82 ~ Relations between Chemical Change, [January, and make the total resistance the same, either by shortening the condu¢ting wire, or by enlarging the zinc and platinum plates, or in any other manner. We now get, as before, exactly double the consumption of zinc, but the quantity of eleCtricity circulating and the heat evolved in the circuit (if the accepted formule be right) the same. How is this? Is it again that the heat evolved by a given weight of zinc is only half under this arrangement, or is only half of it put into circulation? In either case the ordinarily accepted principles are hopelessly wrong. It is obvious that we might in a similar manner, by the use of zinc with different metals as a negative, multiply to any extent the cases to which the formule will not apply. Let us take one more of a different kind. , g. But before describing it let me observe that, in speaking of the heat produced by the oxidation of a given weight of zinc, we speak of what is left of this heat after deducting the amount of cold produced by the evolution of the corres- ponding amount of hydrogen at the opposite pole of each cell. On the principles ordinarily accepted, if this credit balance of heat were zl, the electricity and heat evolved in the circuit should be m/l, and if it were a minus quantity, cold instead of heat should be produced in the circuit. But now take a couple consisting of copper and platinum. The heat produced by the oxidation of an equivalent of copper is said to be 21,885 units, but the cold produced by the evolution of an equivalent of hydrogen 34,462: units. Hence, if the amount of heat evolved in a circuit be equal to that produced by the oxidation of the metal, minus the cold evolved by the hydrogen, the wire should be cooled and not heated; and yet copper is universally recognised as positive to platinum. Or take again an alloy of zinc and copper or other metals, whose. heat-equivalent is the same as that of hydrogen, or 34,462. There can be no doubt that this would be positive to platinum, and would produce a current of electricity, though the heat evolved would be ml; and we should have the anomaly of an eleCtric current passing through a homogeneous wire without heating it. 10. We conclude, therefore, that the whole subject requires a fresh, strict, and full experimental investiga- tiony, What we want to discover is how much heat a certain consumption of zinc and other metals produces when used in different electro-motive combinations with other metals, and what becomes of it; how much circulates through the circuit, and according to what laws. An investigation of this kind would probably show either that a 1871.] Heat, and Force. 83 different amount of heat is evolved in different circumstances, or that the ‘distribution of it is regulated, not according to the resistance of the different parts of the circuit, but partly according to these and partly according to the electro-motive power of the metals used in the cells; and that the total heat circulating in the circuit is not equal to the heat pro- duced by the chemical changes taking place. Ir. Let me add that the laws regulating the amount of heat produced in each part of the external conducting-wire of a battery seem to be tolerably well established, both by the experiments of Miiller, on which they are based, and by corresponding laws, regulating the heat produced in various parts of a circuit by the discharge of Leyden jars; but that where they utterly break down, is when we go on to extend the same laws to the liquid cells of a galvanic battery and to the whole galvanic circuit. Nore. After the above had been placed in the printer’s hands, I discovered the true law which generally regulates the distribution of heat in a galvanic circuit, and published it in the ‘‘ Chemical News,” of Nov. 4th and 11th, vol. xxii., pp. 224, 238. ‘The reasonings by which this law is estab- lished being too late for the present number of the “ Quarterly Journal of Science,” will be published either in an early number of the ‘‘ Chemical News,” or in the next number of the ‘Quarterly Journal of Science.” I will merely add that the law is as follows:—The heat produced in a battery is divided into three parts; (1) That arising from local action which is confined to the battery ; (2) A given portion of the residue also retained inthe battery ; and (3) The remainder which is transmitted through the circuit. Calling these mae, and EL; ; a Sa depends upon, and represents, the 2 electro-motive force of the negative element in respect to the positive element. Indeed, the difference between one negative element and another consists in the property they have of transmitting different amounts of the heat produced in the battery. Portions of H, are evolved in each part of the circuit, including the battery, in proportion to the resistance of each att. Hence if R be the battery resistance, and 7 the exterior resistance of the circuit, HR and Hr the heat evolved in the battery and in the external part of the circuit— lead a HR=H,+H,+=3= na siaur ay a 84 Relations between Chemical Change, [January, I may add that this law is proved mathematically by some of the considerations given above, andconfirmed by comparing various experiments of M. Favre with others of M. Raoult. : Curiously enough M. Favre gives only the heat which is found by experiments to be evolved in a battery, while M. Raoult only gives that evolved in the exterior circuit. Putting the two together, the truth of the above law becomes abundantly confirmed. CHAPTER II. 1. What is the mechanical equivalent of heat? That is to say, what weight will be raised a metre (or foot, or any other unit of length) by the heat which will raise an unit of weight of water from the temperature o° to 1° C., and, vice versa, What mechanical energy will produce this amount of _ heat? Many distinguished physicists fix the number at about 430, taking any unit of weight and a metre as the unit of length; M. de la Boulaye in several papers published in the ‘‘ Comptes Rendus”’ argues for about 180, or less than half that number; Weber and Kohlrausch conclude from their experiments on the mechanical value of electric force, that the oxidation of a milligramme of hydrogen, which produces about 34 gramme-units of heat, will raise 226,800 kilogrammes through I000 metres with a constantly accelerated velocity. Of course, with such enormously discrepant results, there must be a great error somewhere. One calculation makes the equivalent of heat about 430, another about 180, another about 6,000,000,000! For a milligramme of hydrogen produces about 34 gramme-units of heat, and 226,800 kilogrammes x Io00 metres=226,800 x 1000 X 1000 grammetres, which divided by 34 gives more than 6,000,000,000 grammes raised one metre high by each gramme-unit of heat. I find it stated that Joule himself, the great authority on the subject, has at different times, and judging by different experiments, varied between the numbers of 80 and 1300 grammetres as the heat equivalent. 2. But, in the first place, it may be as well to inquire whether there is such a thing as a mechanical equivalent of heat. There may be,orthere may not, but we venture tosay it has never been proved ; and why are we forced to suppose that the same quantity of heat must always produce the same mechanical effe¢t, whether applied by means of the dilatation of different kinds of gases or of solids, or liquids, or in the many other ways in which it can be applied, and vice versa? That the same amount of fuel produces the same amount of energy, whether it is consumed in the steam 1871.] Heat, and Force. 85 engine, the horse, the dog, the swallow, the wasp, the gnat ? At any rate, we may observe that the very phrase is certainly amisnomer, and a misnomer of such a kind as tohavea fatal effect in producing a false conception of things. For mechanical energy just as often produces cold as heat; it may produce either heat, or cold, or neither. In fact, as a general rule, though with notable exceptions, every pushing or compressing force produces heat, and every pulling or expanding force cold. Place a weight ona pillar, and the weight produces heat in the pillar; hang it on a wire, and it cools the wire. Place it on a pillar, which pillar is itself hanging by its lower end on wires, and it will produce neither heat nor cold. The heat produced in the pillar may be made exactly to counterbalance the cold produced in the wire. In the same way, in a fire-syringe, use force to press down the piston, it produces heat—heat enough to kindle tinder; but use the same force to pull up the piston, and it produces cold. Combine two fire-syringes together, one within the other, or in any other way, and let equal forces push one piston down and pull the other up; neither heat nor cold will be the final result. So, also, put a pressure on water at a temperature above its greatest density, and it produces heat. Below that temperature it produces cold. At that temperature it produces neither heat nor cold. Hence we see the same pushing force produces at one time heat and at another cold; and, similarly, a pulling force, tending to expand water, may produce either heat or cold, according to the temperature of the water. The phenomena which point to —273° C.as the absolute deprivation of all heat possibly only tend to show that at that temperature a further condensation of air would produce not heat but cold, and that further cold would expand, not condense, air. There is just as much mechanical energy in a lump of ice which will produce I00 units of cold as there is in a lump of coal which will produce roo units of heat; there is | as much stored-up power in a glacier as in a coal-mine. When our coal is exhausted we may quarry the icebergs of the poles and make them do the work which coal now does forus. No amount of heat in a body can produce any effect till that body comes into contact or communication with some other body hotter or colder than itself. So that, in reality, force is produced, not by heat or cold, but by the restoration of the equilibrium of two bodies or parts of bodies unequally heated, and mechanical energy produces neither heat nor cold (except accidentally), but simply a dis- turbance of the equilibrium in the heat of two bodies or 86 Relations between Chemical Change, [January, parts of a body. This disturbance or restoration of equi- librium might be so contrived as to produceno outward effect at all recognisable by our instruments. Take, for instance, a cylinder, supported at the lower extremity, and pierced with a number of vertical holes passing through it, through which holes pass wires fastened to the upper surface of the cylinder. Now a weight or weights hung to these wires would cool the wires and heat the cylinder, and by increasing indefinitely the number of wires and perforations of the cylinder, the heat and cold produced would be so blended as to be incapable of being detected. This is exactly the con- dition in which water exists at its maximum point of density. The heat and cold produced exactly balance each other. Now let us take Joule’s famous experiments, on which, one may almost say, the doctrine of the mechanical equivalent of heat is founded. He churned various liquids in a calorimeter and measured the increase of temperature. But in this kind of motion, as, perhaps, in all cases of friction, there is a pulling exertion of force, as well as one of pushing. Behind the arms of the paddle-wheel in the churn the liquid is pulled, and is pushed before them. Hence we might expect cold to be produced as well as heat, but the thermo- meter will only show the balance of heat over cold. From these and such like experiments, therefore, we can draw no trustworthy conclusion whatever as to the amount of dis- turbance of equilibrium which has taken place. 3. Now take again M. Favre’s elaborate experiments with a galvanic battery. He formed a galvanic circuit, in which he placed an ele¢tro-dynamic engine. He placed the battery in one calorimeter, and the engine in another. He found that the battery working alone without the engine produced 18,682 units of heat for every gramme of hydrogen evolved. When the battery worked the engine, but without raising any further weight, he found that the battery calori- meter produced 13,888 units of heat, and the calorimeter in which the engine was placed, 4679 units, making together 18,657 units; whence he concluded that the other 25 units were absorbed and disappeared in working the engine. He next made the engine raise 131°24 kilos. a metre high, and found then that the battery calorimeter showed 15,427 units of heat, and the engine calorimeter, 2947, making together 18,374units. Henceheconcluded that the remaining 308 units were absorbed in the 131°24 kilogramme-metres of work. He > consequently deduced that the mechanical equivalent of heat was Soph or 426. Now let me give reasons for 1871.] Heat, and Force. 87 thinking that this experiment is wholly inconclusive. First, is it not exceedingly strange that when the engine did no work the battery calorimeter absorbed only 13,888 calories, but when the former raised 131°24 kilogramme-metres, the latter should register 15,427, thus showing that when the engine did no work, it (the engine) exercised a much greater comparative resistance and absorbed much more heat than when it did the work? Then, can any serious conclusion be built on a difference of 300 units out of 18,682? Is not this difference quite within the limits of accidental error? Indeed, the difference is much less than differences shown in other experiments of M. Favre where he had no engine to do any work. But there is a very much more serious objection than either of these. Supposing the numbers to be strictly reliable, is there not a much simpler explanation of the phe- nomenon? M. Favre does not tell us how the magnetic engine worked, but doubtless it worked as most of such engines do (chiefly at least) by pulling iron keepers to the electro-magnets. Now, by this action the iron is expanded, and this pulling or expanding action, as we have shown, usually produces cold, and hence the disappearance of 300 _ units of heat. Ifthe engine had worked by pushing instead of pulling, that is, by repulsion instead of attraction, should we not have had an increase of heat instead of a decrease ? We have every reason to conclude that we should. Un- fortunately the apparatus required for repeating these experi- ments is so very costly and delicate that very few persons are in a position to repeat them, and M. Favre himself has either never repeated them, or if he has, as he seems to have done, he has never given us the full results. This one single experiment is the only one of the kind of which he has published the result. In the accounts of his later experiments he has never published the number of the calories evolved in both the battery calorimeter and the engine calorimeter, but only the former; and a calculation of what the latter ought to be, ‘but not what they actually were. 4. And to setagainst this single experiment of M. Favre, we have numerous experiments of M. Soret, in which he finds results totally discordant with those of M. Favre. In the “Comptes Rendus,” xlv., 301, 380, M. Soret gives us the result of his experiments. He placed an electro-dynamic engine in a calorimeter to ascertain the effects of its working. Unfortunately, he gives us very few details, but he says (as we should expect from what we have just said) that the results were very discordant with each other. When using a brass calorimeter he found that the effect of 88 Relations between Chemical Change, ([January, his engine working was to produce instead of absorbing heat. This he attributed to induced currents in the brass; but using a glass calorimeter, the conclusion to which he came, on the whole, was that it made no difference whatever in the calorific effects, whether the engine produced work or not. Such are also the conclusions to which he afterwards came after some years offurther experiments. At any rate, the only experiments he gives us in which the working of the engine made any difference tend to show that the engine produced not absorbed heat. We can only say, then, that the whole subject is at present in a state of chaos, and that no legitimate conclusion can be drawn without a new and care- ful experimental examination of the whole of the facts. 5. Let me point out next how eminently unsatisfactory are the conclusions drawn from the experiments of Weber and Kohlrausch. As we said before, they drew from these the inference thata milligramme of hydrogen producedele¢tricity enough to attract 208 tons at a distance of 1000 metres in opposition to gravity—that is, to raise anything less than 208 tons 1000 metres, with a constantly increasing velocity. But I venture to say their experiments were wholly incon- clusive. For how did they operate? They first measured the attractive force of the electricity contained in a Leyden phial. They then examined what effect this had in moving a magnetic needle, placed ina galvanometer. Next they tried what was the quantity of water which, in its decompo- sition in a circuit, corresponded with the same motion of a magnetic needle. Comparing the two they drew the deduc- tions I have just mentioned. But here was the fallacy. In order to prevent a spark passing, and to enable the electricity in the Leyden phial to move the magnetic needle, they passed the current through a long column of water. But they seem to have forgotten that if, instead of the column of water, they had substituted a great length of wire of corresponding resistance, and had formed that wire into a number of galvanometers, the electricity in the Leyden phial would probably have given the same amount of motion to many thousands of magnetic needles, instead of to one, and, consequently, that these conclusions were probably wrong many thousands of times over. I ought to say that I have not read the account of these experiments in the original, but only the description of them given in Watts’s ** Dictionary of Chemistry ;” so that it is possible I may have misunderstood them. 6. Other philosophers have been as much out in their calculations. Régnault calculated how much was the ee 1871.] | ‘Heat, and Force. &9 utmost force which could be got out of steam, supposing there were no waste; but, unfortunately, on examining the work actually done by existing steam engines, it was found that they produced two or three times as much work as he had calculated to be within the limits of possi- bility. I find, also, that Sturgeon states that Professor Page in America has produced from a galvanic battery nine times as much work as Joule and Scoresby had proved to be the utmost possible, according to their computation of the mechanical equivalent of heat. And I much doubt whether any philosophers have yet properly laid down the very first principles of the question involved. No doubt there are many cases in which, where the circumstances do not vary much, it may be convenient to ascertain the usual amount of energy derivable from a given amount of heat, and the provisional assumption of the rule may be practically useful ; but to proceed beyond this, and to lay down an universal law, that heat has a definite and invariable mechanical value is unphilosophical, and, to my own mind, inconsistent with known facts. A given amount of heat applied to expand air will raise ten times the weight that it will if applied to expand vapour of turpentine, and one-and-a-half times as much asif it were applied to expand steam. It may be answered, ‘‘ Yes; but it also expands the vapour of turpentine or of water, as well as raises the weight!” True, but this is not mechanical energy as measured by foot-pounds raised; and to assume that it is equivalent to it is to beg the question at issue. 7. I have shown that the very term ‘‘ mechanical equiva- lene on eat’ is in itself fallacious. Ii there be any mechanical equivalent of the kind it is not an equivalent of heat, but of the disturbance or restoration of the equilibrium Smear. But the question now arises, 1s there such a maximum equivalent? Or can we, by skill and contrivance, increase indefinitely the amount of work to be got out of a given disturbance or restoration of this equilibrium? Take two separate pounds of water, differing from each other and from the temperature of the air by a given number of degrees of temperature ; mix them together, and you get no work out of them; but connect them together by a bar of copper of a temperature between the two, and you get one end of the copper enlarged and the other diminished, and a series of changes and motions going on, till all parts of the water and copper at length arrive at an equal temperature. We have now got some work out of them. Now put one at one pole of a thermo-electric battery, and the other at the other VOL. VIII. (0.S.)—VOL. I. (N.S.) N go Relations between Chemical Change, [January, pole, and we get a current of electricity, magnetic, and other forces, all brought into play, and we get a good deal of work out of them. Next put them at the poles of another thermo-eleCtric battery composed of metals differing in thermo-electric power from the former battery, and we accordingly get more or less work out of them, as the case may be. Is there any limit to this? The answer to this question requires proof. 8. Now to turn to the aspect of the question as presented in a galvanic circuit. Is there any necessary connection, under all circumstances, between the heat evolved and the magnetic force produced? Do they bear any proportion to each other? It is often assumed and stated that they are the measures of each other. Let us show that they are not. It is pretty well agreed that 7, being the intensity, and y the resistance of the external part of a circuit, H (the heat of the exterior circuit)=72?xv. But though many persons have asserted or assumed that other forms of energy vary as the heat, yet I think no one has ventured to maintain in so many words that the force or energy varies as 172X¥r. Almost any experiment would instantly show that this was not true. What is the mathematical expression for the energy is by no means determined. Quot homines tot sententi@. It is pretty well agreed that the action of a wire on a magnetic needle varies as 1x1,/ being the length of wire. But when we come to an ele¢tro-magnet this will not hold. Some say its attractive force on soft iron varies as 2x77; this seems the prevailing opinion, but it is certainly not true; or, at least, true in exceedingly few cases. I have examined and compared more than 1200 ex- periments by different persons; and though it certainly varies as some function of / and some function of 7, yet, under different circumstances, it seems to vary almost as any function of / less than /?, and any function of z less than 7. In faét, it seems to vary under different circumstances, according to laws which are as yet almost wholly unknown. But this we may, I think, safely say that it does not vary as the heat. Again, the law which connects the portative power of a magnet with its attractions at various distances is by no means uniform. To show clearly that there is no connection between the heat and other forms of energy in a wire, take the very instru¢tive experiments: published by Mr. Gore in the “* Philosophical Magazine,” of October, 1870. He took two helices of the same length; one made of platinum wire, the other of copper wire; he placed them at equal distances from a magnetic needle, and so arranged . 2071.] Heat, and Force. gl them in the circuit as to act on the needle in opposition to one another. The platinum evolved very much more heat than the copper wire, and, indeed, soon became red hot; but they both acted on the needle with exactly equal forces. So that clearly heat is not necessarily any measure of magnetic force, though, under certain accidental circumstances, it may be so. g. The state of things revealed by comparing M. Soret’s experiments with M. Favre’s is something very remarkable. M. Soret has confirmed (by numerous experiments) M. Jacobi’s conclusion that when a magnet is doing actual work it increases the resistance, and consequently diminishes the consumption of zinc; while M. Favre’s experiments clearly show that a magnet whilst doing work absorbs less of the total heat of the circuit than whilst it is doing no actual work. These two facts, apparently both thoroughly’ well established, seem utterly inconsistent. How are they to be explained? Is it that M. Favre’s magnets by working produced cold, and so diminished the calories shown in their own calorimeter, whilst, at the same time, by the repeated approach of the magnetised soft iron armatures to the magnets they produced counter currents of electricity, and so produced heat in the circuit, of which the battery, by its higher resistance, took the lion’s share, and consequently exhibited in its own calorimeter? At any rate, I think it is quite plain that we have not yet got to anything like the bottom of the subject, and that our present theories cannot account for the facts revealed. to. Take another case in which we make a battery do an unlimited amount of work. Put in the circuit a cell or voltameter, having no ele¢tro-motive power of its own, such as a solution of nitrate of silver with silver poles. Then, for every equivalent of zinc consumed, an equivalent of silver will be carried from one pole to the other. Now put two such cells in the circuit, and then every equivalent of zine will convey two equivalents of silver the same distance ; and by repeating the process we can make an equivalent of zinc move any weight of silver a certain distance. It may be said we lose time: Yes; but the: only time we lose is the time which it takes for the electric force in the first instance to traverse the circuit. The current once established, equal amounts of silver are conveyed an equal distance in equal times, by a consumption of zinc which may be diminished to any extent. Does not this prove, then, that we may make a certain amount of zinc do any amount of work, with this only condition, that it takes so much = Q2 Relations between Chemical Change, ([January, longer before it begins its work; but the work, once begun, goes on at an equal pace? If this be not so, then all the long-established elementary laws of definite eleCtrolytic action.are wrong. And so, also, if, instead of inserting more voltameters, we increased the distance of the poles in a single voltameter, so as to increase the resistance, we should in the same way increase the distance to which an equivalent of zinc could convey an equivalent of silver, and so make every equivalent of zinc do any number of times the amount of work it did before. And we have nothing to do but to increase the size of the electrodes and dimensions of the vessels containing them to make an equivalent of zinc convey any number of equivalents of silver any distance in any time. Electrolytic experiments have usually been carried on with the poles on a horizontal level. It would be curious to try what effect would be produced if one pole were placed over the other, so that the silver had to be lifted up, instead of conveyed horizontally. Would the power of the electric force be as indifferent to the force of gravity as it is to the resistance of the liquid to the horizontal motion of the silver? Where there is no opposing electro- motive force at work, no resistance or length of circuit, less than infinite, can reduce the electrolytic or magnetic force to nil; and at every point in the circuit, however long the circuit be, this force is equal, and equal in equal lengths. Even supposing the poles in a voltameter to be placed one over the other, vertically, one would say, judging from all analogy, that the only result would be that it would merely give an additional resistance to the circuit, and so diminish the intensity and rate of working ; but that still an equivalent of each element of an electrolyte would be conveyed in each cell according to Faraday’s law. And to counteract this additional resistance all we have to do is to enlarge our cells and plates. The experiment of placing the electrodes in a voltameter of nitrate of silver or sulphate of copper vertically over one another would seem to be almost an experimentum crucis of the truth of the theory of a mechanical equivalent of heat. 11. Does there not, then, exist a power in nature for force to multiply force—even in the same way as life is multiplied by life through successive generations, and one living being may in due time become a thousand without losing its own vital energy? Or, again, as one magnet may make a thousand other magnets, and yet all the while rather increase than diminish its own strength? Conservation of energy is true in mechanics. A pound weight at a metre of height from i) Ral Be 1871.] Heat, and Force. 93 the ground can at most, as we find by experience, only lift by its own descent another pound to a metre of height. And again, all experiment tends to show that. multiplication of matter is impossible. But it is not proved that skill cannot get more and more mechanical force out of a given amount of chemical change or heat. ‘This I venture to say isa question still at issue. In multiplying an electrical or magnetic or even a caloric power we are creating nothing ; we are simply disturbing or restoring to a greater extent an equilibrium. Whatever amount of electrical, magnetic, or caloric power we get, there is still the same quantity of electricity, magnetism, or heat in the world; all we do is to disturb an equilibrium ; the more positive electricity we get, the more negative we get, pavi passu, and so in magnetism, so in heat ; we cannot get north polarity without getting at the same time south; nor produce heat without at the same time producing virtually in some shape or other an equivalent of cold. The total amount, reckoning the plus to credit and the minus to debit, remains still the same. In mechanics we are allowed to balance plus motion in one direction against minus motion in an opposite direction ; and the slightest preponderance on one side or another will set in motion an illimitable amount of mass. Why may not the same principle be applied to ele¢trics, magnetics, and calorics? Cannot skill, mere skill, produce a less or greater disturbance and restoration of equilibrium, and so more or less force? What an enormous generation of force and disturbance of chemical and calorific equilibrium can we produce by the mere application to a forest of a lucifer match or spark, which having once commenced the motion, this constantly reproduces itself, till in a few hours carbon and hydrogen have all become carbonic acid and water, and a grand disturbance of calorific equilibrium has been produced which takes ages to restore itself, till at last, again, in due time, by the re-growth of the vegetation, carbon, hydrogen, oxygen, caloric have recovered their original state; and all this grand revolution and restoration of forces—this regular round of chemical activity—has been produced by a lucifer match or spark? Nothing has been gained or lost; the heat produced by the combustion has again been;absorbed by the growth of vegetation; and the carbonic acid, water, and other compounds have again resolved themselves into the shape of wood and leaves. And cannot we by skill, without force, induce more or less of the combined ele¢tricities plus and minus, or of the combined heat and cold in matter, so to Separate themselves that, by their re-combination, they may 94 Our Patent Laws. (January, _work for our benefit? This is the great physical problem of ‘problems for science to solve. But if this is a problem beyond our power to solve, the next best thing to be attempted is to harness in our service the great powers of nature, to catch and force to our own use the circuits of electricity which are for ever circling the earth, and which hitherto we have only used to direct our magnets, and guide our ships; in faét, to mount, as skilful and well-taught Phaetons, the chariot of the sun, and force its four mighty steeds, the strongest and mightiest of all steeds, heat, light, eleCtricity, and chemical force, to work for us our ploughs, and looms, and engines, and drag our railway trains. Twice, indeed, every day as I sit and watch the Thames, I see the moon drawing up and down along its silent highway trains of barges; for does she not as she goes round the earth, pull with her its tidal waters, with barges and all else that floats on them? I should like to see the sun put to the same kind of work, and as he rejoices like a strong man to run his race, to yoke him by the Harness-cords of induction and conduc- tion, and radiation, so as to force him to do for us more work, and to act more at our will and guidance, than we have hitherto forced or persuaded him to do. Vill. OUR, PATENT, LAWS: HIS subject so closely connects itself with the progress of scientific civilisation and the rights and comforts of many scientific men, that it cannot but command our attention; and the perusal of a recent bookentitled “‘ Abolition of Patents—Recent Discussions inthe United Kingdom and the Continent,” has much interested us. As to the laws them- selves, we believe them to be unmanageable by lawyers, and they reflect no honour on legislation. They are consequently, and without blame to individuals, carried out in such a way as to corrupt all that are concerned, deceiving and robbing both the inventor and the public, and inducing all to deceive in return.| The inventor pays for a patent, and obtains literally no protection unless he can pay for that also. One shilling would register his invention as fully as his present fee, and if the invention is printed in a journal many would be purchasers and it might pay itself. In the present state of things patentees with no inventions come with crushing weight of gold, and prove to the satis- faction of ignorant juries that they have the truth, whilst | ) \ J a a 1871.] Our Patent Laws. 95 the real inventor has a mere imitation. For this the legal profession are to blame for not inventing shorter processes of eliciting truth. We do not blame the men but rather the technicalities of statutes and the antiquated habits of thought among lawyers. It is a symptom of decay when men think long over trifles and give themselves to hair splitting. It is a symptom of vigour when the hairs are made into a rope and cut through with oné stroke. We know the value of details in proper places, but life is short, and he who does not know how to dash through the spray of trifles may sit long in the wet before he lands on the shore. We cannot by a statute law destroy the power of money, and the influence of cunning and falsehood. It is not sound ‘reason which throws the blame of such proceedings as we have alluded to on inventors, on lawyers, or any one class. Government may not know in all cases to whom a patent is due, but it will know in very many cases, and the incredible proceeding of selling a patent to twenty individuals more than one to have it solely, which we are told has been done, ought to be quite impossible among us. Some officers have an interest in giving patents, but an officer who can act thus does not fulfil a useful function. If it is a rule of his office, and not his personal fault, the rule should be rescinded. This, surely, must be an infringement of right. Itisnolaw of nature or mind; it must at best be some poor paper law that usurps that lofty name. The lawyers are a powerful race; their minds are acute and their impetus is great. They are respected for many reasons, and one is because they are believed to carry, and do carry, within them the wisdom of the ages regarding the various relations of society; we know much of this is true. Still, as a rule, the lawyer in a court is merciless and not refined. He probes feelings, he exposes private relations, he hurts tender hearts, he is determined to win, fighting over the dead and dying. Men with delicate feelings and keen sense of justice are outraged in courts and leave as soon as possible. Inventors, real inventors, being often of this class, seeing no hope for themselves unaided, give part of their rights to others, who, being determined to make as much money as possible, begin the crushing, pounding work of atrial. The invention may bea real one, but in such rude hands it is soon made to assume all the offensive appearance possessed by the unreal. No distin¢tion is made— truth-loving scientific men are ill-treated by men accustomed to deal with law-breakers, and the result is the same to a spec- tator as if no real invention or inventor was ever connected with 96 Our Patent Laws. (January, the question. The character is often crushed in this way, and the man feels as if his moral nature were injured along with his property. No wonder, then, that we find so many of the best of men refusing to fight their inventions before a court and refusing to become patentees. Circumstances have made it appear as if the law and the lawyers had conspired with the wealthy to turn them aside by ridicule, by force, by disgust, by anything that will rid the court of their presence. It is not wonderful, then, that the word ‘ patentee” is not necessarily applied to a respectable man only. Hf the Government gave a patent to an honest man for an honest invention, the name of patentee would be courted ; a patent would be exactly like a grant of land for services. All inventors, however, are not thin-skinned and weak in fighting with the world. There are some who can defend themselves, but to do so must demand much vigilance. It requires wealth to carry out their ideas, and wealth to make them of benefit to the whole world. There are now living patentees who have altered the manufaCtures of Europe and America, and developed resources that would make a nation rich, and who have been able to fight their own battles without fear of lawyers or of courts. Inventions such as those of Bessemer have made the patent list stand respected by the pirates; but there are still men amongst us who have devoted years of their life to an object, hoping to gain at least a living by making their work useful to their fellow men. The result—they become hopeless, and in a sense paupers. Give patents under better laws. There is much in this age to contend with. The old rights, and, indeed, the only known rights, of landed property seem to many to be unjust, and communism is making way among the nations of Europe. It would seem asif a certain mode of thought pervaded a whole generation. Whilst the poorer classes seek the re-distribution of land in some distri¢ts, the richer classes seem to think it right to demand a certain community of property in the thoughts of others. We are sorry, therefore, to find single-minded and unselfish men, in Parliament and out of it, opposing this latter class of property. They are doing work from which they will shrink when they see its real meaning. It is a higher aim, but no less a piratical aim. In France a leader of temporary fame said that all property was theft. In England we find members of Parliament saying that there can be no property in ideas. Ifaman spends all his life in digging land and growing corn he may sell it, but if he spends his life in ts ae 1871.] Our Patent Laws. 97 making a machine to cut the corn, he is to give the benefit of his labour to mankind. A speaker at the Social Science Congress tells us that if a man discovers anything of benefit to mankind he ought to give the result of his discovery as an act of benevolence. Will any one give his land or his crops out of benevolence? And yet these come to many men without labour. People imagine that discoveries are floating fancies and are caught by some men as readily as such, whereas they are almost invariably the result of much labour—to some more and to some less, exactly as property falls to some men more and to some less easily. Since certain of the speakers on patents have ventured to bring them in as opposed to natural law, they must be contradicted. Arguments they do not give, so we are saved much trouble. There is a property in ideas; and if we consider fora moment we find there is no perfectly stable property except in ideas. You may have property in land, but some one may come and dispossess you. Your property in ideas, however, you have power to retain against kings, armies, and barristers. We do know, and itis sadly true for humanity, that such property is so entirely in the power of a man that he can take it with him out of the world. This he cannot do with land, and yet a man is found to say that there is no property in ideas. Now this is no quirk or fancy. The property is real in the fullest sense; and it is valuable ; it can be exchanged for all the various goods of the world, and it can be made by labour whilst it cannot be made without it. The property in ideas has all the essential characteristics of other property. And the world must not give up its rights ; it must hold good the title-deeds to ideas, because without such justice it will suffer more than is consistent with prosperity. Knowledge must have its rights as well as the mere possession of matter, and the world must agree to this as a law. The reasoning adopted for free trade seems to solve the question to some minds; they do not seem to consider that neither Adam Smith, Cobden, nor Bright ever defended the right ofamantotradewithanother’sproperty. Thesethinkers object to protection, but they never object to protect a man in the possession of his own house, and certainly never advise anyone to thrust his hand into another’s pocket and take value from it, still less to take the very secrets of another’s mind and sell them for selfish purposes. Honour forbids it ; when, however, men are all honourable neither patents nor policemen will be required. We were very much surprised to see that even a law Ot. Vill. (O.S.) VOL. I. (N.S.) O 98 Our Patent Laws. [January officer of the crown confounded patents with monopolies. The natural law regarding patents is so simple that those who see it can answer the question regarding monopolies at once. Is amanto have no monopoly of his own house or his own lands, or will you so grind him down that he will have no monopoly of his own brains? Natural monopolies are established facts; artificial monopolies for the interest of individuals not conferring a proportionate benefit on the state it is now agreed are unjust. The great East Indian Company was a monopoly, and is put down after a long and prosperous life. Itis a natural monopoly when a man has the sole right to use his own wit, and for convenience sake we give the same to him: who first takes possession of land. It is wonderful what may be done with a word. Where is logic in the application of the same word to the exclusive use for fourteen years of a man’s own invention? How unfair the comparison! Fourteen years is seldom enough for the perfecting and introduCtion of an invention. ‘To gaina reward, an inventor must work very hard and spend much money, and he gives all his knowledge to the public whether he gains anything or nothing. The state takes freely, but it gives nothing. The public takes and buys perhaps from the inventor, but only if it can profit by the purchase. If an inventor is allowed no time to be the sole user of his discovery, he is treated as a useful but despised tool that takes out the chestnut from the fire and gets burnt for its pains. One of the greatest difficulties with which inventors must contend is the occult change in the mode of thinking,~ produced by the study of law and the study of science. It will be long before scientific men will be able quite clearly to make their distinctions felt before lawyers. ‘The scientific man has his ideas of law and sequence founded on natural phenomena. So far his ideas are imperfect, because founded on imperfect appreciation and mixed with the ordinary prejudices of education, society, and personality. But the lawyer has his ideas of law from books written by lawyers, and containing the imperfect reasons, and the traditional errors, as well as wisdom of many generations. He has his mind framed in a faulty model. Of course we know the reply. These model thinkers have studied carefully, and the wisdom of ages is in their books, but at best it is a wisdom altered every year and condemned by scores of parliamentary bills, whilst the a¢ts of natural law may be seen by everyone in unchanging order and beauty. The two laws produce two classes of mind. This is known in daily life. A barrister, | _ 1871.) Our Patent Laws. 99 an advocate, or judge, unless after special study, never fully comprehends a scientific idea; there is a quast intelligence which passes before the multitude and amongst themselves, but scientific men always retire from them in a hopeless state. The battle between lawyers and scientists is only beginning. It will be fought by lawyers as men fight who have hitherto had no opponents but of their own class. They are already pre- paring a somewhat inferior place for the scientific man, who with his natural laws has inaugurated a mode of reasoning diverging from that of the bar, and has in this beginning of the revolution stood out as all reformers do as a lawless person, whose character must be carefully scrutinised. There can be no doubt of the struggle. We cannot doubt theend. Natural law will rise and statute law will fall—how far we cannot tell, perhaps, till it agrees with natural law. This time may be distant, but the approach of it has begun, and barristers now beginning life ought to prepare for it by a sound drilling in scientific knowledge, and, if possible, by a little hand labour in the workshops of mechanicians or physicists. | : The inevitable tendency of the mind of the bar, caused as it is by education and habit, must not lead us to speak evil of the men. How could they do otherwise? Neither do we suppose they deny what wesay. Weall resemble that which teaches us. A similar result occurs among scientific men. They are not supposed to be perfect, even if they do study natural law;.no, on their side is too often shown too much ignorance of the social aspects of a question, and these can be best seen by the barrister. They are.also too hard and self- ° sufficient, receiving a habitually unyielding trait from the necessarily unyielding character of natural law—a character- istic which constant study has transferred tothe man. The two must learn to work amicably, but there is a large district now in the occupation of the law which must be taken by Scientific men. Some of the arguments used against patents are to us very amusing. The speaker, who says that a patent is a monopoly, nevertheless adds that, in early times, *“if new kinds of business were to be established, it was not unreasonably thought safe, or even needful, to allure by pro- mise of exclusive privileges.” So it appears that even mono- polies might be given in the old way to men who did not invent but who did what was equal, namely, brought new manufactures from other countries. We think so, too, under certain circumstances, and as a patent is for a description of 100 Our Patent Laws. (January, anew manufacture, the right cannot be given more fairly than to him who describes it, but we would add that he must carry it out or attempt to do so within a given time. We know as a certainty the history of several patents, and we know of none which were successful without labour. But even if a patent were for some idea that suddenly struck a person, why should we refuse to reward him for giving it to us. Ifa man finds a diamond we do not steal it from him. Are not men’s minds rushing through the regions of thought to discover the good and the useful? Why should we steal what they find ? We agree with M. Renard—‘‘ Common sense and equity would join to say that when a scientific man indicates a dis- covery or an invention, that discovery or invention remains at the disposal of every one if the finder does not claim the exclusive right to work it ;” supposing it to belong to the class to be made useful in the arts. How different this clearness from the wanderings of M. Chevalier and others, who are not sure if a man can claim an idea, because many can hold it at the same time. The patentee does not attempt to keep others from the idea; he wants only his reward for teaching it. Surely this is agree- able to all law and justice. Mr. Scott Russell is quoted in the recent discussions as giving an objection to patents. It is that the moment any- thing is patented everybody avoids it, lest he be subjected to an expensive prosecution. Surely it is the same thing with your purse—everybody, except the thief, avoids taking that, lest he be subjected to crime and disgrace. Mr. Grove’s objection took us by surprise. He says that it is natural that people should yield to the patentee for fear of prosecution. Perhaps this is the same as Mr. Scott Russell’s without the comedy. We do not question Mr. Grove’s experience, and we say, what a serious responsibility it is, then, to give a patent to a man. But the law seems to sell patents to anyone. It says, like all hucksters, “‘ Caveat emptor.” To us these patents have a character not different from forged notes if given to more than one individual, or useless to him. Mr. Grove makes another objection. It takes too much time to trythe patent cases. On this,also, we have to quarrel with the management of patent law affairs. The power of arriving at the main point in a discussion seems to be lost ; we drivel for days over trifles. Perhaps we have not legal men enough. We have known twenty men brought two hundred miles and sent away in an 1871.] Our Patent Laws. IOI hour, because the barristers were busy with other matters. The law itself being bad, the results of course are saddening. We have heard that mercantile men have sometimes set about conducting arbitrations in order to diminish the evil, but the result has been that they have tried to imitate barristers, and have of course been still more unfortunate. The ‘‘ Journal of Jurisprudence ” calls patents “ trading monopolies,” quite forgetting, we think, the charaCteristics and fine distinctions. Mr. Webster, Q.C., says, truly, that people rush after patents for applications of some new idea or invention. Yes, unfortunately; and it is for lawyers to give the true limits, if possible. Mr. Meadows has a horror of patent laws, and says “‘ one evades it (a patent) by designing something else, perhaps as good in itself, but giving one infinite trouble without any advantage to the holder of the patent.” The patent here must have been doubly good. So good that it was necessary to imitate it, and two inventions were obtained for the public instead of one. Mr. Hale has an objection to patents because so many useless ones are obtained and they obstru€@t the trade. Why use them if they are useless? If you do not meddle with such useless things they will not hurt you. Many known men are brought forward as being much troubled by patents. Probably people had invented things before them, unfortunately taking advantage of their priority of existence by making prior inventions. One says that considerable inconvenience and great ob- struction to the trade are caused by patents. One authority finds that many people are thinking of the same thing, and it is not fair to give the patent to him that first runs to the office. There may seem a hardship here; we have known not a few cases. We have picked many a much desired book from a catalogue and sent for it. But some one had it before us. Is there a scientific man, thirty years of age, who has not had nine-tenths of his best ideas anticipated? Did your own friend not catch that fine trout which had run off with your hook half an hour before? Werethere not a hundred applicants for that situation and only one gotit? We must not sink into helpless weakness. He who wins must enjoy. Do not let us seek impossibilities or grow sick with sen- timentalism. A witness from Liverpool finds it very hard to move in any direction without treading on a patentee’s toes. The meaning of this we suppose to be that he cannot improve his 102 Our Patent Laws. [January, _ business without the assistance of patented inventions, as he cannot invent sufficiently for himself. Surely he ought - to thank the patentees for helping him. _ Mr. Montague Smith, the judge, has found great incon- venience from the multiplicity of patents which the inventor has had to wade through to see that he has not been anti- cipated. The meaning of this seems that the inventor was obliged to see if the Government had not deceived him by selling the rights to some one else before him. The law again failing to come up to our expectations. Sir W. Armstrong then says, You cannot give a monopoly without excluding other persons who are working on the same subject: That is a truism. Let him who works and finds first be rewarded. Will you reward those who find after him ? Mr. Platt gives a good objection to patents as they are, but it applies wholly to the law or to that law-officer who allows patents, or both, and we again say that no one has sufficiently explained how thoroughly unjust are the;workings of our patent law. Mr. Woodcroft, to our mind, settles the question against , the mode of giving patents. ‘I know of existing patents which are but old inventions as old as the hills.” Another objection is that so few are remunerative. We need not answer this. With such laws it requires great power to fight your way. Inventors are not rich men, and the power of wealth and legislation may crush them still further. If lawyers were to invent such laws as would pro- tect these men the generation would bless them, and true in- vention would increase. Mr. Richard Roberts is quoted as saying that a quart of ale will bring out secrets of trade, so impossible is it to keep a process without a patent. We know that the system of bribery is common enough. There are men who have laboured for years, and discovered something, and desire to give it to their children. When it can be carried on by one man he will have no patent. There is even one business which has had a secret for three generations. If patents are not given men will resort to this mode of secrecy, as they do now in Prussia. In that country patents are so few that it seems the belief that only bribery or friendship can gain one, and works are closed up to visitors to a great extent. We cannot doubt that the till of late slow develop- ment of industry in Germany has been owing to the want of decision in giving patents; want of openness, and, so far as ‘we can make out from Germans, want of official honesty, 1871.] Our Patent Laws. IO and want of communication among manufacturers, are ‘ productive of the same stagnation as the want of roads ina country. Some persons are quoted as saying that if there were no artificial rewards the inventors would be as numerous as at present. That is only half true. Poems would be as numerous; mathematicians would be, and scientific men generally might be, but even Sir W. Armstrong forgets the expense of bringing out an invention. A man might give his idea for the honour, but would he give the time and expense of trying it, and, until he does so, the idea is valueless to the public. The public gives the patentee nothing for his idea. ‘They pay for the soap he makes, or the pens, or the cannons; and the country knows to its cost how much money experiments on the latter require. Not only would real finished inventions be fewer, but it is a necessity of the case that it should be so. The inventor obtains money on loan frequently, to be able to complete his invention. It is only because he can afterwards make money by having the exclusive use of the patent for a while that he can borrow money. If no patent, then no experi- ments. There would be as many ideas, perhaps—that is to say, the brains of men, might wander as much—but a finished invention is a serious and expensive affair. We have too often seen the inventor in the throes of his study and struggle of experiment to doubt this, and we have seen it last too many years to be led by the fancies of men who seem never ‘to have lived at the heart of the nation, nor seen the method in which the blood moves. But do the patent laws present to us no difficulty? Do We pretend to see all clearly where others have been perfectly blind or given to ghost-seeing ? We have no such satisfaction. Still, without pretending to know how to settle the question, we have confidence that every difficulty ‘will be cleared away regarding English patents by a broad, common-sense view of an invention. We should like to get rid of the exclusively lawyers’ mode of viewing facts, and. of his humiliating and time-wasting formalities. When we look abroad we have no difficulty in seeing how some countries can get on without patents. Switzerland has none. , It obtains inventions by taking from other countries such as suit it. Beingsmall, it has the best of it. So pra¢tically does Prussia to a great extent. Nations are selfish, and if they can gain by robbery, they will find a new name for the offensive act. The opinion of Count Bismarck on patent laws is to be 104 Our Patent Laws. [January, seen at page 185 of the work quoted. He, like others, sees **no natural claim on the part of an inventor to be protected by the state.” In other words, there are men the fruits of whose industry he will not protect; this is simple monopoly and despotic respect of persons. We can easily see why an old aristocracy ignores the value of invention, just as monied men dislike it. It raises the inventor to power as well as wealth. After this, the opinion of Count Bismarck can be of no value in our eyes. He thinks that ‘‘the remarkably developed system of communication and conveyance now-a- days, which has opened a wide field to real merit, and enables industrial men promptly to reap all benefit of production by means of enlarged outlets for their articles will, generally speaking, bring those who know how fo avail themselves before others of useful inventions to such an extent ahead of their competitors that, even when no permanent privilege is longer admissible, they will make sure of a temporary extra profit in proportion to the service rendered to the public.” This is not to the purpose. The sharpest man who can first come forward isto bethe gainer. ‘The inventor is not the sharpest, is never the sharpest man, and can never make such gains as we have spoken of. We can imagine a statesman asking himself, by what means can he evolve most invention out of the nation? whether by wringing it out unjustly or acting with kindness ? Rulers have tried the first in all nations, but of late they are finding out that honesty is the best policy. We can best benefit a nation by letting every individual feel that he is governed with justice—that he and his property are free. We have been told of inventors who had rich men looking in at their windows to see the new machines; these were the sharp fellows that knew how “to avail themselves of discoveries before others,” and which are especially favoured by Count Bismarck. One suggestion, however, strikes us as good fora distant day. It is to have an European and American system. ‘‘ The parliament of man, the federation of the world,” will rule in time, and it cannot be begun so well by any as by the authors and inventors. Until that is fully developed we cannot hesitate in saying that he who destroys patent right has begun a movement which will do incalculable evil. He, however, who teaches us how to remodel the laws will benefit us in a way such as he did who first brought law among mankind ; he will be to us as a “‘ Rhadamanthus, Ruler of the Blest.” We cannot see M. Renard’s difficulty, who thinks that, because coal is a natural product, no one can claim a 1871.] Our Patent Laws. 105 reward for discovering it. We say the discoverer deserves a reward, and gladly would we give one to him who gave us a new fuel. Inventors are expected to do all the benevolence, and to give away their lives for the world, whilst men with “ real property” enjoy it themselves. If you destroy the property of inventors, the time may come when the title-deeds of other property will be asked for. We fear such a time, and such men as will make the demand; and we prefer to see property safe, and to respect the feelings of man as fully as we would respect the cannon or the bayonet. Or is this opposition to the property of thinkers the new form that a material philosophy is taking? Is it denying the existence of all property that is not made of solid matter; determined to enjoy the material reward of thoughts without itself having the trouble of thinking ? Weare told that only three per cent of patents are very successful, but if 5000 are taken out annually, that makes 150 very successful patents every year, and as they go on for 14 years we have 2100 of this higher class in action at a time, making money, and, of course, giving occupation to many individuals. The owners are all busy men, stimulated by the love of honour and money, and all that money brings. Wecan scarcely imagine the amount of work to keep 2100 successful patents in motion. ‘They have a power extending to the most distant places, and their influence at home is felt in every household without exception. If three per cent be really the amount of very successful patents, let us ask if it is a small amount. If too young men entered Cambridge with the hope of being mathematicians, do three per cent obtain any honours whatever? Of 5000 men who write poems, do three per cent ever become known? Of zoo men in any profession are three per cent made public charaCters by their talents? Of1oo men that become medical practitioners, how few are ever known to publish a book, or to advance the science? Of the thousands who have begun chemistry within the last 20 years, scarcely five can be got to filla professor’s chair when demanded. Do three per cent of those who enter Parliament ever become distinguished? To stop short. Three per cent of mankind do not rise above their fellows So as to become prominent, then why should we expect more from patentees? But the world does expect more, and we believe that even more would be found if the laws were just, for at present they do not elicit inventions from that class of mind well able to invent but afraid to fight before lawyers. VOL. VIII. (0.S.)—VOL. I. (N.S.) P 106 | Our Patent Laws. [January, However, there is still the real difficulty—what is an invention? One man makes an invention as described in the volume; another crushes him by manufacturing 300 specimens at a time instead of one. If the first man’s patent is held good, the delay of the second for 14 years may be a great loss to the country. Would it not, in such a case as this, be fair to compel the second to pay a sort of royalty to the first ? Many of these difficulties that have oppressed the bar would be easily removed by a tribunal of common sense. Could the lawyers not invent such a tribunal? We admire a judge against whose opinion an Act of Parliament was brought. He replied, ““ What! am I to put the young man in a position that will almost certainly ruin him merely because of an Act of Parliament.” It is such judges as this last that we think able to do justice by the use of common sense. Is there no hope of obtaining for them freedom of action. We must now for a moment revert to that frequent assertion that inventions rise up in various places at the same time; the argument seems to be that nothing is lost to humanity by the loss of an individual mind. This, we think, would not be asserted by any of the men who have spoken on patents. ‘They would be afraid to see the actual meaning of theirown words. But if men will rush upon great problems of psychology and history without considera- tion, we can expect only a superficial result. If we look at the subject from the narrow field of the daily patent lists only, we may imagine that somany minds are occupied that nothing can be lost; but if we look on the history of invention, we come to a different opinion. There are obvious conclusions drawn by _ several individuals at a time, many of such patents we should be glad to get rid of entirely, but good sound inventions come — rarely to more than one mind at a time. It is to the individual that Nature and Providence give the rich, rare gifts that advance humanity. The history of the few has been the history of human progress, and a lost thought may roll for ages through creation without finding a mind to comprehend it or a brain to make it useful to society. 1871.] (107 ) PROGRESS IN PHYSICS, (IncLuDING Licut, Heat, Evectricity, METEOROLOGY). LIGHT. Mr. C. B. Boyp has devised a novel form of telescope. It consists of a plane speculum, having an equatorial motion, which reflects. an object to a conclave speculum at a distance; this in turn reflects the image to the eye- piece situated behind the plane mirror; a hole in the centre of the latter allowing this to be done. This arrangement brings the mirror and eye-piece close to the observer, while, at the same time, it enables one to have a very long telescope, without any great extra expense, for an observatory: it combines, in fact, both observatory and telescope in one construction. A thirty-foot telescope needs an observatory that will cost £10,000; while in this arrangement the observatory proper needs only be sufficient to cover the equatorial, the instrument itself being 50, 100, or.500 feet long. In a letter from Professor Young, of Dartmouth College, N.H., we learn that he has succeeded in obtaining photographs of protuberances on the sun’s limb. They were obtained by attaching a small camera to the eye-piece of the telescope and opening the slit somewhat widely, working through the hydrogen line near G. Three-and-a-half minutes’ exposure was required, and the double- headed form of the prominence is evident. Professor Young has also designed a new form of spetroscope for observations upon the solar spots and protuberances, a detailed description of which appeared in the ‘‘Chemical News,” vol. xxii., p. 277. Although the instrument has the dispersive power of 13 prisms of heavy flint, each with an angle of 55°, it weighs less than 15 pounds, and measures only 15 inches in length, 8 in breadth, and 44 in height. The collimator and observing telescope have each an aperture of {ths of an inch, and a focal length of zinches. The light from the slit, after passing the collimator, is transmitted through the lower portion of a train of six pftisms of heavy flint glass, each 2} inches high, and having, as stated above, a refracting angle of 55°. A seventh half-prism follows, and to the back of this is cemented a right-angled prism, by which, after two total reflections, the light is sent back through the upper part of the same train of prisms, until it reaches the observing-telescope. This is placed directly above the collimator, and firmly attached to it. A diagonal eye-piece brings the rays to the eye in a convenient position for observation. Observations of the Solar Protuberances.—With this instrument Professor Young has observed about forty different prominences. Fig. 11 represents a small one, which was observed upon Fic. 11. the E. limb of the sun on September 14th, about 4.30 p.m. From the point marked a, which was very brilliant, a small fragment detached @ itself and rose towards a', enlarging @ in size and growing fainter as it rose. It disappeared (from faintness) in about twelve and a half minutes, at a distance of 2' 30’ above the limb of the sun, as determined by the time, 8°5'", which was occupied by the intervening space in passing over the slit of the spectroscope. Allowing for the obliquity of the motion to the parallel of declination, the length of 108 Progress in Physics. [January, path passed over by this cloud was more than 90,000 miles, and the velocity above 120 miles per second. Fig. 12 represents a prominence observed September 2oth, at 4 p.m., on the S.E. limb. _(Pos. S., 60° E.) It was a nearly vertical stream, made up of spindle-formed filaments, and had attained the enormous height of 3' 20", or go,000 miles (determined, as in the case above mentioned, by a time observation, corrected for inclination). It was very brilliant near the base, and at two or three other points along its length. At 4.30 it was nearly gone, only a few faint wisps of cloud remaining. Another observed on September 27th, at 4.10 p.m., and situated on the W. limb of the sun, is represented in Fig. 13. It was formed of separate, well-defined narrow streamers, which appeared to consist of matter, first violently eje@ted, and then as violently deflected, by some force acting nearly at right angles. The altitude of the highest point was 1' 25", the length of the whole about ar 20013 Bright Lines.—In the spetra of different protuberances, the following bright lines have me been observed, the numbers referring to Kirchhoffs scale: C; Dr; Dz; D3; 14743; 15153 613; 02; 63; b4; 1990; 2001; 2031; F; 2581°5; 2796; A—17 in all. On one occasion, September 27th, the base of a prominence on the N.W. limb, close to a spot just leaving the limb, exhibited as many as twelve or fifteen short bright lines between E and F, which are not included in the above enumeration. The line, 2581°5, which was conspicuous at the eclipse of 1869, seems to be always present in the spectrum of the chromosphere, and shows the form of its upper surface or of a protuberance nearly as well, though not so brightly, as the 2796 line. It has no corresponding dark line in the ordinary solar spectrum, and, not improbably, may be due to the same substance that produces D3. The reversal of the sodium and magnesium lines is not at all uncommon. In some instances these lines were so bright that, on opening the slit, the form of the prominence could be made out through them. This was the case with a small hand-shaped prominence observed on September 27th. Comparing the form thus seen through D,; and Dz, with that given by D3, it appeared that the sodium line was sufficiently developed for observation only along the edge and at one or two bright points in the prominence, most brilliantly neither at its summit nor Fic. 12. Pie. 13. Fic. 14. its base. Fig. 14 represents the appearance (the slit was perpendicular to the sun’s limb). The case was similar with the magnesium lines. Spectrum of Solar Spots.—The most interesting phenomena were exhibited by a large group, which was first observed near the E. limb on September roth. Changes of wave length were frequent in its neighbourhood. Figs. 7 and 8 1871.] Light. 109 represent the appearances assumed by the F and C lines respectively, at the times indicated below each figure, during an observation on the afternoon of September 22nd. The point where these changes of wave-length occurred was at the western edge of the penumbra. The C and F lines were reversed in some portion or other of the group nearly every time Professor Young observed it. On September 22nd, the sodium lines were both reversed for several hours, while D3 appeared as a dark shade. On September 28th, again, at 4 p.m., the southern nucleus of the group (which at this time contained four large umbre, Fic. 15. Fig. 16. C. B25 2,38 vn 24a 26 Bh besides many small ones), reversed all of the following lines, viz.: C; Dy; D2; D3; 14743 613 ba; b3; b4; F3; 2796; and h. All of these were con- spicuous, except 1474; D3 and bz especially so, and the latter (a nickel line) showed considerable changes of wave-length, alternate increase and diminution, which were not shared by its magnesian neighbours, 6;, 62, and by. At 4.05 p.m. the brilliance of the F line increased so greatly that it occurred to Professor Young to widen the slit, and to his great delight he saw upon the disk of the sun itself a brilliant cloud in all its stru€@ture and detail identical with the protuberances around the limb. Indeed, there were two of them, and there was no difficulty in tracing out and delineating their form. Fig. 17 represents them as they were from 4.05 HIG. 17. to 4.10; Fig. 18 gives the form at y 4.15-20. ‘They were then considerably fainter than at first. During the Ma intervening ten minutes the other lines | of the spectrum were examined, and it was found that the form could be distin&ly made out in all the hydrogen lines, even in 4; but that the reversal of the other lines, including D3, was confined to the region immediately over the spot-nucleus, where the smaller but brighter cloud terminated abruptly ; = or, rather, originated. The larger one faded out at both ends. When the clockwork of the equatorial was stopped, Fic. 18. ih nt a “ae : ; y ue pl : i pear ots eee SDS () ae tee the luminous cloud took 16°7 seconds of time to traverse the slit which was IIO Progress in Physics. [January, placed parallel to the hour-circle. This indicates a length of at least 130,000 miles, without allowing anything for the foreshortening resulting from the nearness of the sun’s limb. By 5 o’clock the clouds had nearly disappeared ; a little rack alone remained. In the telescope this group of spots, from their first appearance, exhibited a strong yellowish tinge, which appeared to overlie all the central portion of the cluster. So conspicuous was it that several persons, unaccustomed to astronomical observation, noticed it at once before their attention was called to it. The penumbra of the group was unusually faint. At a late meeting of the Manchester Photographic Society, Mr. Kershaw showed some very interesting photographs, illustrating one of the many uses made of photography in the war raging on the Continent. The subje@ con- sisted of the important portions of Paris newspapers cut out, arranged in columns, and photographed on tale. What would form nine columns of a newspaper was copied on a space about two inches by one inch and a half, and was perfectly legible with a glass of moderate magnifying power. These talc photographs left Paris by balloon post. Mr. Browning, the eminent optician, has arranged a spectroscope in which the prisms are automatically adjusted for the minimum angle of deviation for the particular ray under examination. In spectroscopes of ordinary construc- tion, when several prisms are employed, a great deficiency of light will be FIG. Ig. Vr, Tats Lm qty Uy noticed towards the more refrangible end of the spe@rum. This arises from the fa& that the prisms are adjusted to the minimum angle of deviation for the most luminous rays which occupy the middle of the spectrum. Fig. 19 shows the method in which the change in the adjustment of the prisms to the minimum angle of deviation for each particular ray is made automatically. In this diagram, P Pp, &c., represent prisms; all of which prisms, with the . exception of the first, are unattached to the plate on which they stand, the triangular stand on which the prisms are hinged together at the angles 1871.] Light. 1 corresponding to those at the bases of the prisms. To each of these bases is attached a bar, B, perpendicular to the base of the prisms. As all these bars are slotted and run on a common centre, the prisms are brought into a circle. This central pivot is attached to a dovetail piece of two or three inches in length, placed on the under-side of the main plate of the spectroscope; which is slotted to allow it to pass through. On moving the central pivot, the whole of the prisms are moved, each toa different amount in proportion to its distance in the train from the first or fixed prism on which the light from the slit falls after passing through the collimator, c. Thus, supposing the first prism of the train opposite c, represented in the diagram, to be stationary, and the second prism to have been moved through 1° by this arrangement, then the third prism will have moved through 2°, the fourth through 3°, the fifth through 4°, and the sixth through 5°. As these bars are at right angles to the bases of the prisms, and all of them pass through a common centre, it is evident that the bases of the prisms are at all times tangents to a common circle. Now for the contrivance by which this arrangement is made automatic. A lever, L, is attached to the corner of the triangular plate of the last prism. This lever by its further end is attached to the support which carries the telescope through which the spectrum is observed. Both the telescope and lever are driven by the micrometer-screw, M. The action of the lever is so adjusted that when the telescope is moved through any angle it causes the last prism to turn through double that angle. The rays which issue from the centre of the last prism are thus. made to fall perpendicularly upon the centre of the object-glass of the telescope, T, and thus the ray of light travels parallel to the bases of the several prisms, and ultimately along the optical axis of the telescope itself, _and thereby the whole field of the object-glass is filled with light. Thus the apparatus is so arranged that on turning the micrometer-screw, so as to make a line in the spectrum coincide with the cross wires in the eye-piece of the telescope, the lever, L, attached to the telescope and prisms, sets the whole of the prisms in motion, and adjusts them to the minimum angle of deviation for that portion of the spectrum. The Paris correspondent of the ‘‘ Engineer,” in an interesting letter sent by balloon post, speaking of the use of the electric light in war, says:—‘‘ War certainly does something for science. The use of the electric light is common to both sides in the present struggle, but the French have used it largely. The apparatus set up on Montmartre is arranged by M. Bazin, and is electro- magnetic. The central cylinder supports four series of double coils, covered with copper wire, enveloped in silk; the cylinder is rotated by a small steam engine of three-horse power, making 400 revolutions per minute. The lamp used is of the ordinary form, with the Foucault-Duboscq regulator. The reflector is parabolic in form, and the whole is surrounded by a shield to hide it from the enemy. This light, from its elevated position, commands the whole of Paris and the plains around. A spectator on Montmartre sees distin@ly the details of the facade of a building which stands 2600 metres off; at 2900 metres a man may be seen standing at a window; at 3000 metres a mass of cavalry or infantry is distinguishable ; and at 4000 metres the dome of the Invalides, with its bands of gold, is brilliant. A man cannot be seen on the dome at that distance, but on walking towards the building all soon becomes clear. On the ramparts, at 3800 metres from Montmartre, the light is sufficient to read an ordinary newspaper. Thus, though the practical effe& of the lamp only extends about 300 metres from its position, the field is illuminated to the extent of 700 metres, for the benefit of all placed between the light and the object. Thus a sentinel on the ramparts can see about 3000 metres from the encetnte, and by this means strict watch is kept upon the plains around the city at night, as far, in one direction, as 1000 metres beyond St. Denis. M. Bazin is now occupied in applying his apparatus to the purposes of night telegraphs, by the adoption of the system of flashes, and with the aid of coloured lenses. A corvette, the Coligny, already possesses such a signal apparatus, and thejsignals are distin@ly visible at more than eight miles distance.” 112 Progress in Physics. [January, The spectrum of the light during the magnificent Auroral display of the 24th and 25th of October was obtained by several observers. From the following abstract of their accounts it will be seen that there is a general uniformity in the results; the presence of hydrogen appearing to be _ established. Professor A. H. Church, of the Royal Agricultural College, writing to the ‘* Chemical News,” says that he was able to observe the spectrum of the aurora as seen at Cirencester. He saw a steady yellowish green line, and frequently a brilliant red line near that of calcium. A pale line was also seen in the green, and a more definite one in the blue—these last not being constant in occurrence. A correspondent of “ Nature,” ‘“‘ T. F.,” observing at Torquay, saw four lines in the rosy portion, and one in the greenish; one strong red line near C, one strong pale yellow line near D, one paler near F, and one still paler beyond. The C line was very conspicuous, and was intermediate in position and colour to the red of the lithium andcalcium. His opinion is that there were two spectra superposed ; the red portions showing the four lines (probably hydrogen) and the greenish only one, near D. Mr. W. B. Gibbs saw two bright lines ; one, a red, looking like the C hydrogen line, and one a greenish gray. Mr. Elger saw a red band near C, a bright band near D, a faint and rather nebulous line, supposed to be near F, and another very faint line between the latter two. Mr. H. R. Progr saw a brilliant red line more refrangible than the hydrogen C line. Mr. J. R. Capron saw a line in the red very much like the lithium line, and a line in the light green like one of the lines from the larger nebulz. It may be of interest .to compare these observations with those of other observers made previously. J. A. Angstrém found the light of the aurora to be almost monochromatic, consisting of a single bright line less refrangible than the red calcium lines. With a wide slit, traces of three other bands were seen. Professor Winlock found the spectrum to consist of four green lines and one blue line. Three of the green lines coincided with lines seen in the spectrum of the corona as observed by Professor Young during the total solar eclipse of August, 1869. Microscopy.—A correspondent of the ‘“*‘ American Naturalist ’ makes the old complaint as to the insecure mode by which dry obje&s are commonly mounted. Paper, paste, and gum are, as usual, the origin of all the mischief, affording no protection against damp, scarcely keeping out dust, and favouring the growth of numerous fungi, which, sooner or later, spoil the preparation. He suggests, as the only remedy, a steady refusal to purchase objets so mounted. This state of things is just as common in England; the majority of dry objects being mounted in the above well-known manner. To those who merely require a few showy preparations to gratify the taste of the moment for sensational objects, these defects may be of little importance, but to the student the storing of objects for reference at, possibly, a very distant period, is a matter of the utmost consequence. No dry preparations should be tolerated unless secured in air-tight cells, and every precaution should be taken not only to exclude damp, but also not to include it; the obje& should not only be thoroughly dried, but the mounting should be done ina dry atmosphere; there is no reason why as much pains should not be taken to keep the damp out of dry obje&s as there is to retain the liquid in the cell in the case of fluid mountings. Our microscopical cabinets ought to be available for the use of the observers of at least the next century. Mr. T. Greenish has examined microscopically the various articles sold as lint. The result appears to be, that those labelled “Lint” consist entirely of cotton, while, with one exception, those described as “‘ Flax lint’? contain more or less cotton, but by an ingenious arrangement of the materials the linted surface is composed almost entirely of flax. There is an idea prevalent that cotton forms an extremely bad application to sores, causing great irritation, and linen 1871.] Light. 113 is generally preferred in dressing : should this prove to be the case any adultera- tion of flax lint would be an undoubted evil, but lint wholly of cotton is used extensively in hospitals, and had it been productive of any bad consequences its use would soon have been discontinued. The peculiar lint known as charpie used in continental hospitals and the marine lint were also noticed. Microscopical examination fails to throw any light upon the alleged irritating properties of cotton, as, although, the fibres are flat, they have a perceptible thickness at the edges, and are, moreover, rounded; the section of a cotton filament being somewhat like that of a thin tube flattened. It was suggested that the cause of irritation was not owing to the form of the fibre, but to its hygroscopic power of twisting when moistened and causing irritation by its movement. Mr. J. W. Stephenson describes a new Erecting Binocular Microscope, which he has had constructed for the purpose of carrying on dissections under moderate powers. The pencils transmitted by the object-glass are equally divided and reflected by a pair of prisms, and again reflected by another prism into the two bodies, which are placed at a very convenient angle for dissecting operations; the-image is, as the name indicates, non-inverted, and the two fields equally illuminated. For ordinary observations the Wenham binocular will be found preferable, not only on account of one-half of the pencil being transmitted without reflection, but also from the facility with which it may be converted into a monocular instrument, But for the especial set of purposes for which it is designed nothing has yet equalled Mr. Stephenson’s instrument, either for comfort or convenience; the definition is also remarkably good when it is used with the low powers for which it is intended. In the “ Transactions of the Devonshire Association for the Advancement of Science,” Mr. E. Parfitt describes and figures twenty-seven sponge spicules from the greensand of Haldon and Blackdown, near Exeter. The specimens, which were obtained by Mr. Vicary, are in remarkably perfect condition, being imbedded in a very friable rock, from which they separated with the greatest ease. Many of the spicules are identical with those of recent species of sponges, described by Dr. Bowerbank, “ British Spongiade.” One, Fig. 13, closely resembles the spicules of Euplectella aspergillum (Venus’s flower- basket). Another, No. 26, is much like the spicules of Pheronema (Holtenia), dredged by Dr. Carpenter, in the “ Lightning ” and “ Porcupine ” expeditions. Spontaneous generation still furnishes matter for discussion; it is a good subject for controversy, and from the nature of the evidence procurable, is not likely to be satisfactorily settled one way or the other. Mr. B. T. Lowne states that he has boiled spores of penicillium in sealed tubes, in a solution of acetate of alumina, and that within twenty-four hours many of them had germinated. This goes very far to prove that some germs cannot easily be killed. If such is the case with spores known to exist, how many included germs that have escaped observation may retain their vitality, in spite of the severe treatment to which they have been subjected. The subject of high power definition, especially with regard to the nature of the markings on the scales of Thysanuride (Podure) and other insets, is now being actively discussed, and will probably give rise to as long a controversy as that on the Diatomacee. Mr. J. Beck believes, from the manner in which fluids diffuse themselves on the scale, that one of the surfaces (the outer when in situ) is smooth, the other, the inner one, corrugated, or strengthened by longitudinal ribs running from the base to the apex of the scale (‘‘ Monthly Micro. Journal,” Nov. 1870). Mr. S. J. McIntyre has examined not only the scales of most of the Thysanurida, but also those of several butterflies and other insects; the result is very fully described in his paper (‘‘ Monthly Micro. Journal,” Jan.). Mr. Slack, from evidence derived from torn and damaged scales, considers that the beaded markings shown by high powers under certain arrangements of the illumination are realities, the tear never passing through but between the beads. Dr. Piggott discusses the subje& from an optical point of view, and calls attention to the means by which false images are produced; he has carefully studied the shadows formed when light is VOL. VIII. (0.S.)—VOL. I. (N.S.) Q II4 Progress in Physics. [January, passed through arrangements of intersecting glass rods, spun glass, and other substances, and endeavours to explain the phenomena of the podura and other unknown markings by reference to the curious appearances so produced. Mr. Slack, as an example of deceptive appearances, cites an instance of minute cracks in a film of silica, which when focussed in the manner most satisfactory to the eye resemble tubes instead of fissures in the thin layer of silica.* Professor Huxley considers that, at present, we have arrived at the end of our optical resources, so far as histology is concerned, and does not believe that more can be seen by the aid of a 1-50th than with Ross’s 1-12th. Dr. Beale invites Professor Huxley, or other skilled microscopist, to examine a preparation to be made by himself, first with a 1-12th or 1-16th, and to make a careful drawing of all that he can discover, and afterwards to continue the observation with a 1-25th or 1-50th, and then to decide whether these higher powers do or do not reveal new strudtural details. Prolonged as the controversy will be, there can be but little doubt that it will ultimately tend to the further improvement of the microscope, by showing where high power definition is defective, and pointing to the means of eliminating errors which possibly may exist even in the best of our present objectives. Referring to the notice in a recent number of this journal, of the remarkable magnifying power of 100,000 diameters having been obtained by a New York pseudo-microscopist, an American correspondent says, ‘‘ It was done by eye- piecing and you know what that amounts to. But it was said that with this power they photographed the Pleuvosigma angulatum, showing dots two inches in diameter. This is hardly a correct statement. Looking at the angulatum through their microscopes, they made drawings of what they thought they saw; then made a pine model and photographed that! It was all done to advance the interests of a well-known manufacturer of cheap microscopes, but the parties have no scientific reputation with us. The photograph is now on exhi- bition in this country, but the true facts (which were related to me by one of the assistants who knew the facts but did not appreciate the rascality) are not generally known.” As we have had no means of judging for ourselves, or of making the necessary examinations, we do not accept the responsibility of our correspondent’s statements, but merely quote them from his letter. The death is announced of the President of the Royal Microscopical Society, the Rev. Joseph Bancroft Reade, M.A., F.R.S. The deceased was one of the founders of the society, also the author of many improvements connected with the microscope and microscopical research, and also a Fellow of the Royal Astronomical and Meteorological Societies. HEAT. M. G. Salet has described some peculiarities of the blue flame of sulphur and some of its compounds. This blue flame is not hotter than red-hot iron, and contains reduced sulphur; but, at the perisphere of the flame, very active oxidation takes place, and sulphuric acid is formed. By the same arrangement the author has shown that the zone of aqueous vapour which en- velopes the flame of burning hydrogen, contains nitric acid and binoxide of hydrogen. ; M. Toselli, the inventor of a very ingenious ice-making machine, states that experience has proved that ice made by his process withstands the influ- ence of a high temperature better than natural ice, or than any other ice obtained by artificial means. To illustrate this fa&t, he adduces the instance that a block of ice weighing 20 kilos., made by the author’s process in 18 minutes, and sent off from Paris to Algiers on the 30th of June last, arrived, properly packed, at its destination late in the afternoon of the 5th of July, the block of ice then remaining still weighing ro kilos. The loss, by fusion, ena journey through a warm climate in the middle of summer was, therefore, only 84 grms. perhour. 100 kilos. of ice made by the author’s process would require, under the same conditions of temperature, 49} days to liquefy it; whereas é * A specimen in illustration was exhibited at the November meeting of the Royal Microscopical ociety. 1871.] Electricity. II5 100 kilos. of the ice artificially made by another process has been found to melt in six days under the same conditions. The secret of this appears to reside in the high degree of compactness and freedom from fissures in the ice pro- duced by M. Toselli’s machine. A short time ago, a fire broke out at the premises of MM. Behague and Paxer, wholesale silk mercers; the fire was, however, very quickly. discovered, and this gave rise to the discovery that it originated inside a large parcel of black-dyed silk which had been returned from the dye-house only 24 hours previously. That black-dyed silk is somewhat liable to spontaneous com- bustion has been a well-known fact for years, but, notwithstanding the researches of Persoz and others on this subject, the real cause is not quite elucidated. In some researches on “* The Simultaneous Boiling of Two Liquids which are not Miscible,” M. A. Kundt gives an account of a series of experiments made with water and benzol, water and oil of cloves, water and sulphide of carbon. The chief point of interest in his results is that two liquids, not miscible with each other when in contaé, boil at a lower temperature than when the most volatile of these liquids is brought to ebullition by itself. Mr. M.G. Farmer, of Boston, has fused the native iridosmine by placing the natural grains in a groove in charcoal, and subjecting them to the action of a current of voltaic electricity from sixty large Bunsen cells, using large platinum wires to make contact with the ends of the groove. He obtained in this manner bars of perfectly compact metal, brittle and very hard. The operation was anything but pleasant, on account of the intense light emitted and the fumes of osmic acid, which attacked the eyes and nostrils, producing the phe- nomena of rose or hay fever, and sunburning the face. Mr. Farmer estimates the temperature of the fusion at about 10,000° F. The object of the experi- ment was to prepare a bar of the alloy for the purpose of electric illumination. On rendering it luminous by an eletric current, he found that when near the melting-point one square inch of surface evolved light equal to 2800 candles, which threw shadows in broad daylight at noon, and produced excellent photo- graphs. The same battery converted solid bichloride of iridium into fused metal as soft and ductile as platinum. Messrs. Mottershead and Co. have just brought out an improved automatic regulator, maintaining constant temperatures in laboratory operations, which is applicable to any operation in which gas is used as a source of heat. When fitted to copper drying closets or air-baths the temperature may be limited to any degree from 75°F. upwards. This apparatus acting automatically, the temperature is unaffected by varying pressure of gas, the common source of accident in ordinary drying closets. Drying closets and evaporating basins are also fitted on a slightly modified plan, in which a reservoir of air placed inside the oven is made to act on the regulator, thus avoiding the necessity of a double copper chamber, and at the same time forming a sufficiently sensitive apparatus for many practical purposes. ELECTRICITY. Dr. J. G. Fischer has described some curious effects caused by lightning striking his house, a detached residence situated near Hamburg; the lightning first struck and demolished a stack of chimneys, and next found its way to the soil along a zinc pipe for conveying the rain-water from the roof downwards ; the pipe alluded to, previously sound, was perforated in three places in a very curious manner; at one of the holes the metal was forced outward, while at the two other holes the metal had been forced inward in such a manner as to close the tube for the passage of water, at the point where the tube reached at the bottom the earthenware drain-pipe; the latter was smashed, the soil which covered it having been scooped out; no fire ensued by the striking of the lightning, nor was fusion of metal anywhere perceptible. The substitution of aluminium for platinum in Grove’s batteries has been successfully tried by Mr. Nettleton. Two small cells, the size of the aluminium 116 Progress in Physics. (January, plates, being 4 inches by 13, decompose water very energetically. The metal aluminium possesses the advantage of costing (for equal surfaces) about one- tenth the price of platinum, being about 5s. per ounce, cut to size. The subje& of the eleGtro-deposition of brass is one of some commercial importance; it has been recently studied with considerable success by Mr. W. H. Walenn. The history of electro-metallurgy, as set forth by Smee, in 1851, comprises only that part of the subje& which relates to the eleGro-deposition of metals from their neutral or acid solutions. With some isolated exceptions, no alkaline solution is there treated of. Mr. Walenn uses potassic cyanide and neutral ammonium tartrate, when mixed with water, to form the solvent solution for brass. The quality of brass (yellow or red) depends upon the heat of the solution. Acid solutions, in general, give a spreading, or matted deposit; alkaline solutions, a bristling one. The contac of the coating is promoted by working the solution hot. Thearticle should be pickled, scrubbed with sand, washed, scrubbed with a portion of the depositing solution, and then placed in the depositing trough; after deposition the article is washed, and dried in hot mahogany sawdust. Complete protection from rust, anda satisfactory coating for any purpose, is given by the use of an acid-depositing bath subsequent to that of the alkaline bath. The self-recording instruments at the Kew Observatory, showed a large amount of disturbance of the magnetic declination and horizontal force during the progress of the Aurora of the 25th of October. Dr. Joule also observed the changes which took place in the magnetic dip, at Broughton, near Manchester. The most remarkable variation occurred during the interval from 6h. 15m. to 6h. 23m. G.M.T., when the dip increased from 69° 8’ to 70° 30’. Apropos to a statement which appears to be authentic, that there has been in Versailles during the investment of Paris a telegraphist who has secretly rendered most important services to his country, by transmitting information from the head-quarters of the German army to the imprisoned authorities in Paris, the ‘‘ Electric Telegraph Review” enters into some interesting specu- lations on the subject of secret telegraphy. It is considered by most persons impossible that telegraphic communication could be carried on between Versailles and the besieged capital without being discovered; for, they argue, even if we could not hit upon the line wire, we should obtain speedy information of the locality where it terminates, and where this ingenious individual manipu- lates his instruments. Is a secret telegraphic circuit, hidden from all ordinary means of search, and capable of being worked from one extremity without the exhibition of batteries, signalling instruments, or even a conta@ key—nay more, without any appearance of “line” and ‘“‘earth”’ terminals, beyond the resources of modern telegraphic ingenuity, to say nothing of modern eleGrical science? Our contemporary thinks not. It appears certain that the subje& of secret subterranean telegraphs is one which has from time to time received some attention in France; and it is one which, sooner or later, would probably well repay alittle investigation on the part of ourown Government. The data, even as at present understood, seems to be nearly, if not quite, sufficient to realise the object in view. LEmployés in the secret service would need to be trustworthy and thoroughly efficient telegraph clerks, trained to send signals rapidly and accurately without a ‘“‘key”’—or with merely a common-place latch-key, bringing into interrupted contaé& an innocent-looking bell-wire and a harmless gas pipe. They would require also to be thoroughly conversant with the art of converting the tongue into a delicate receiving instrument. The lines must be buried deeply, and excavations for other purposes, such as gas and water pipes, and sewers, should be utilised when possible. The choice of the locality for one terminal is of importance; an out-of-the-way bedroom ina public building, or in premises adjoining it, is generally to be preferred. The outward appearance of the terminal has been already hinted at; it may bea veal bell wire,—the point where this is conneéted with an insulated wire, led below the foundations of the building, being of coure care- fully concealed. “Earth” of course can be obtained wherever there is a gas or water pipe. Devices such as these are very simple; but it does not seem to » a 1871.] Electricity. 117 occur to the mystified authorities at Versailles that, by means of them, telegraphic communications may be sent, and even received, without any of the paraphernalia of an ordinary telegraph office, provided some of the latter are at the other extremity of the line-wire. If the French telegraphists have outwitted the Germans at Versailles, the latter have retaliated at Meudon, where a complete underground electric telegraph was discovered in one of the cellars. For days the unconscious French were sending messages, which were “ tapped” by the Prussians to no great purpose, however, as they were generally in cypher. Varley’s Singing Telegraph.—Mr. C. F. Varley, C.E., of Fleetwood House, Beckenham, Kent, has just invented some telegraphic apparatus, whereby two, three, or more messages can be sent on one line wire at the same time, and without interfering with each other. This invention, therefore, is likely to prove of considerable value, since it will so largely increase the transmitting power of line wires at present overcrowded with work, and will save the cost of hanging additional wires between London, Liverpool, Manchester, and other large centres of industry. Another remarkable feature of the invention is, that the instruments sing, or rather, “‘ hum” their messages. The Morse alphabet is used ; a loud, long hum is given for a dash, a quieter and a shorter hum is given fora dot. When one of the instruments is at work it sounds as if a big bee were teaching a little bee to exercise its voice, because, as a general rule, the loud and softer sounds are given alternately. The sounds are caused by the vibrations of a thick iron wire, the instrument being something like a violin, five feet long, with one thick string. The first instruments, made for experi- mental purposes, worked well; the writer read off messages by them, which Mr. Varley sent from another part of the house, through a hundred miles of wire, of the electrical resistance of that ordinarily used on land for telegraphic purposes. By the new apparatus, waves are superimposed upon the currents ordinarily used in working a Morse circuit, and the receiving instruments respond to the action of these small waves. Suppose a long rope, with a weight at each end, were passed near the ends over two pulleys; signals might be transmitted by pulling the rope at either end, and lifting the opposite weights up and down; if now, at the same time, vibrations or waves were set up in the rope by striking it with a stick, and an observer could read off messages sent by these small undulations, we should have an effe@& analogous to the new system of telegraphing. 3 Let A B, Fig. 20, be the line wire; Mr. Varley attaches a condenser, D, to it ; the other side of the condenser is attached to the sending apparatus, which Fic. 20. Fic. 21. charges and discharges the condenser with great rapidity ; consequently, these impulses add to and take from the line a number of small waves, without affecting the mean magnetising power of the ordinary Morse current. The diagram shows how the apparatus is connected for receiving messages. The “key”? or commutator, E M H, when not in use for sending messages, keeps the condenser, D, in contact with the receiving instrument, x, through the 118 Progress in Physics. [January, metallic stud, M; the other side of the receiving instrument is connected with the earth at N. When the key is depressed, conta& is broken at M, and the condenser, D, is placed in communication, through the stud, H, with the wave- generating apparatus beyond R. A convenient condenser to use is one of three microfarads. The vibrations of the tuning-fork, a, Fig. 21, are employed to set up the waves, and the fork is caused to vibrate incessantly by power obtained from the battery, B, one pole of which battery is connected with the fork; the two light springs, E F, have small platinum studs at the end, and when the fork is at rest, the light piece of metal, r, attached to one of its legs, is in conta@ with the spring, E. A current then passes from E, round an electro-magnet, the poles of which are shown at H kK. Instantly, of course, the prongs of the fork are pulled outwards by the attraction of the magnet, conta& with E is broken, and with F established ; the fork, however, at once springs back again, and thus continuous vibrations, at the rate of about 200 per second, are produced. The battery power used for generating the waves is ten-quart Daniell’s cells. Some electro-magnetic apparatus is fixed between the tuning-fork and the condenser, and this apparatus sends the impulses into the condenser when the key for sending signals is depressed. The principle of construction of the receiving instrument is shown in Fig. 22. ADB E is the iron frame of a sounding-board, which board is 4 feet 6 inches long between the bridges, H H. The thick iron wire, A B, is No. 14 gauge, and its tension is regulated by the two screw nuts shown at the ends of the iron frame. ‘This wire passes through the hollow helix, nN, which helix is 3 inches FIG. 22. long and } inch internal diameter. This coil is attached to the iron frame, and does not touch the sounding-board. Two horse-shoe magnets, K K, are placed one on each side of the wire. One end of the coil, n, is connected with the con- denser while a message is being received, and the other is connected with the earth. The rapid currents from the condenser magnetise the wire within the helix, so that it is attra@ed or repelled by one of the two magnets, K K. By this means rapid vibrations are set up in the wire after the wire has been “tuned,” by turning the screw A or B, so that it has a tendency to vibrate synchronously with the pulsations of the fork at the sending station. When it is properly tuned, very feeble currents will give a distinctly audible sound. There are various ways of augmenting the sound if desired, by means of vibrating tongues, strained diaphragms, the use of the stethescope, and other appliances; the signals can also be made visible by optical apparatus, or be made sensible to the touch. In the experiments above mentioned the sound was full and clear, without such additional aids. There are also various ways of originating waves in the sending portions of the instrument. By this apparatus, while messages are being transmitted from London to Brighton by the ordinary Morse apparatus, through one line wire, the singing instruments may be placed at half a dozen intermediate stations on the same wire, and each station may communicate with its next neighbour, without interfering with the main line work. The singing instruments on one length of the wire are prevented from interfering with those on the next length by the interposition of an electro-magnet, for an eleGro-magnet offers at the first moment considerable opposition to the passage of a current of electricity, so may be considered to be opaque to rapid waves. By the arrangement just described, half a dozen or more messages may be traversing the same wire at the same time. Or, if there be no intermediate stations, two messages at the 1871.) Electricity. 119 same time may be traversing the wire from end to end, and even here the limiting power of transmission of the wire is not reached. Two sets of wave- signals may pass through the wire independently of each other, if a sufficient difference be made in the periods of the two sets of waves; and Mr. Frederick Varley, who made much of the apparatus, informs the writer that he has very readily sent three messages from end to end of the same length of wire at th same time. Where the distance between any two singing instruments exceeds 100 or 150 miles, the difficulties in signalling with them are increased; transmitting intermediate stations may therefore be necessary for very long distances. The instruments have also to be tried on ordinary telegraphic lines, to find out their real practical value. Whether the commercial value of Mr. Varley’s plan of telegraphing be very great or very small, it is certainly one of the cleverest scientific inventions of the present age. Siemens’s Electrical Pyrometey.—Mr. C. W. Siemens, C.E., F.R.S., of Great George Street, Westminster, has recently invented an ingenious pyrometer, the principle of which is, that as the electrical condudtivity of platinum, iron, and other metals decreases as they rise in temperature, their increase of resistance to the passage of the current is a measure of the heat to which the metals are _ subjected. The principle of construction may be explained by the aid of Fig. 23, in which FABisa tube of pipe-clay, and the length between the projections, A and B, has a screw-shaped spiral groove cut on its outer surface; the F1G. 23. length of this part of the tube is about 3 inches. A spiral of P fine platinum wire lies in the groove, each turn of the platinum spiral being thus protected from lying in contac with its neighbour by the projecting edges of the groove, by which plan of insulation the current is forced to pass through the whole length of the fine wire. pD is a little platinum clam, connected with one pole of the battery, and the position of E this clam on the spiral regulates the length of platinum wire through which the current shall pass. By this plan of adjust- ment, all the pyrometers constructed by Mr. Siemens are made to agree with each other. At F, the ends of the thin platinum wire are connected with very thick platinum wire, and higher up, near £, where the heat of the furnace is less felt, the thick platinum wires are connected with thick copper wires, shown at P; from E to F, these connecting wires are protected by clay pipes, as shown in the cut. When this arrangement has to be used, the whole of it is dropped into a thick metal pipe made of iron, copper, or platinum, according to the heat of the furnace to be tested. The lower end of this outer pipe is shown at kK M, and when it is used, the spiral aA B, lies inside it atn M. AtR there is a very thick collar of metal in which the heat accumulates, and this prevents the cooling action of the length k R (most of which does not enter the furnace), from interfering with the accuracy of the indications. The ends of the wires, P, are connected with suitable and very delicate electrical apparatus, by which the increasing electrical resistance of the hot spiral is measured. To measure low temperatures on the same principle, several miles of insulated iron wire are enclosed in a tube containing dry air, and hermetically sealed. This instrument is very useful to measure underground temperatures, as the indicating part of the apparatus may be far away from the thermometric portion. Dr. Carpenter used this appa- ratus, with some modifications, in ascertaining deep sea temperatures. 120 _ Progress in Physics. (January, Thompson’s Syphon Recordey.-Among the inventions of Sir William Thompson, is one, which has recently come into use for registering feeble indications, made by weak currents of eleGtricity, such currents, in fac, as are used in working Atlantic cables. The principle of the invention may be explained by the aid of Figs. 24, 25, and 26. In Fig. 24,Ns are the poles of a powerful permanent magnet, capable Fic. 24. Fic. 25. b fk of lifting several pounds. To still further increase the power of the magnetic field Mr. Varley’s plan of placing a piece of soft iron, s n, between the poles without touching them is adopted. ABDEis a very light coil of a small number of turns of fine wire, through which the feeble current from the line- wire passes. This coil is kept stiff by being stretched over pieces of any light stiff material, like the boom in the rigging of a ship. By Fic. 26. this arrangement, whenever the current from the line passes through the coil, the coil will move in or out according to the A direction of the current. Fig. 25 is a diagram of the same arrangement viewed from above, nN s being the poles of the magnet, and 8 the D F coil. A silk thread, p, conneés one side of the coil with one of the bends of the syphon, E, so that as the coil, B, moves to and fro, the leg of the syphon, E, moves to and fro near the surface of the slip of paper, R, which is drawn by E clockwork over the brass roller, F F. This roller is insulated with vulcanite supports, and is connected with an electrical machine, in consequence of which the liquid or ink in the capillary syphon made of glass spirts out against the paper, y and thus the motions of the syphon and coil are recorded. Fig. 26 is another view of the same apparatus, A being the vessel containing the ink, p the syphon, © the brass roller, and F F the paper. New Experiments in Diamagnetism.—The following experiments were made ~ with a powerful electro-magnet belonging to Lord Lindsay; the iron horse- shoe is four inches in diameter, and the bent bar is seven feet long. The two helices are of copper wire nearly a quarter of an inch in thickness, and a very powerful Grove’s battery is employed to excite the magnet. The experiments hereinafter described were devised by Mr. C. F. Varley. Some rings were prepared, consisting of pieces of bent copper wire, soldered together at the ends; the wire was 7, inch in diameter, and the ring 1} inch. When the ring, a, Fig. 27, was inserted between the movable poles, ns, of the electro-magnet, each pole 2 inches square, the ring fell gradually and slowly until the upper part of the ring, c, was level with a, or about 4 of an inch below the — upper surfaces of the two poles. It then fell rapidly until the lower portion of the ring arrived at b, when it commenced to fall slowly once more, and soon ~ afterwards it passed out of the magnetic field, when it fell at the ordinary rate. — While the ring was going into the magnetic field it experienced great resistance to its fall; the moment it passed into a sensibly uniform magnetic field, it fell 1871.] Electricity. 121 unimpeded; on attempting to get out of the magnetic field it experienced the - same resistance as in the first part of its fall. The ring was seven seconds in falling through the two inches of magnetism. But on breaking the soldered junction, k, of the ring, A, and thus preventing the formation of eletric currents therein, the ring, to all appearance, fell between the poles as rapidly as Fic. 27. if there had been no magnetism 3 there at all. Therefore, electri- city, which has no weight, actually helped to keep the : heavy metal copper in suspen- K \ sion in the air, notwithstanding ) the attraction of gravitation. Mr. Varley concludes from this experiment that ‘a current of electricity is as solid and material to a magnetic field as is a plate of iron to a bar of copper.” The following is another curious experiment made with Lord Lindsay’s large magnet. A horizontal piece of vulcanite, v, was placed between the square poles, N s, Fig. 28. An end view of one of the poles, with the vulcanite, v, is shown in Fig. 29. When one of the copper rings was placed rather more than half way in between the Fic. 28. FIG. 29. poles, as in the cut, the magnetisation of the magnet drew the ring inwards. When the ring was a little less than half way in, as shown by the dotted lines, the magnetisation of the magnet repelled the ring. Although the movement of the ring was not more than 3 inch, yet there was power enough to roll it up an incline of thirty degrees. Another experiment made by Mr. Varley is shown in Fig 30. Two hollow Fic. 30. poles were placed upon the magnet; when the magnet was not magnetised, and a burning taper, a B, was thrust in until the burning wick was opposite the opening between the poles, sufficient air did not pass between them to Support combustion, and the flame was extinguished after burning a few seconds, On the other hand, when the poles were magnetised, and the taper VOL. VIII. (0.8.) VOL. I. (N.S.) R 122 Progress in Physics. [January, was thrust in as before, the burnt air was driven out in the dire&tion shown by the arrows, and the flame continued toburn. On demagnetising the magnet the flame went out, and on immediately magnetising again, the wick, which had become nearly black, began to glow again, and clouds of smoke poured out at each end of the hollow poles in the dire@tions shown by the arrows in the cut. This smoke was of course driven out by the diamagnetism of the heated vapour. On one occasion the heat produced in the wick was sufficient to re-light the taper. Some, but not all, of the experiments herein described were shown a few months ago by Mr. Varley and Lord Lindsay, to the Prince of Wales, ata soirée held at the house of Mr. John Pender, 18, Arlington Street, London. The Deposition of Iron on the Poles of a Magnet.—At the last meeting of the British Association, a paper was read by Mr. Frederick Varley, F.R.A.S., on ‘‘ The Deposition of Iron on the Poles of a Magnet,” which paper, it will be remembered, attracted considerable attention. He has favoured us with the following details of his plan of coating the magnet; these details may be of interest, as it is difficult to get a satisfactory deposit, notwithstanding the discoveries of Jacobi in this direction. The electro-deposit of iron was thrown down on the poles of a permanent horse-shoe magnet, composed of several bent bar-magnets. Each of the poles - was 7 of aninch square. This magnet was made the electrode of a battery, and the poles were immersed about ? of an inch in the solution hereinafter described. A Daniell’s battery of one cell with large plates, and having a resistance of 0°33 Ohms was used. The plating solution consisted of equal volumes of saturated solutions of sulphate of iron and sulphate of magnesia mixed together, after which sufficient water was added to make the sp. gr. of the liquid 1400. The plating was effected in a large cell holding about 3 pints of solution, and from the size of the cell the resistance was practically equal in all dire@ions. The cathode consisted of two small pieces of iron, placed at opposite sides of the cell, the magnet being over the centre; about 1 inch of iron surface was exposed on each side of the cell opposite to the poles of the magnet. The magnet was allowed three months in the solution to receive its electro-deposit of iron, and during that period the mean temperature was 60°. At the end of this time it was found that the iron instead of being uniformly deposited on the surfaces of the poles, as in the case of ordinary ele@trotyping, was deposited chiefly on the sharp edges of the poles. A bridge of iron was not made from poleto pole as might have been expected, or as would have been the case had iron-filings been scattered over them, but, on the contrary, the growth was equal on all sides of the square poles. The greatest deposit was at the corners of each of the poles. This experiment opens the way to a new field of research. For instance, experiments may be made on the deposition of iron inside helices, and the plan shows how magnetic rays may be stereotyped. It also suggests that experiments should be made with thallium, bismuth, and other diamagnetic metals which are easily eleCtrotyped ; the cells in which the work is carried on should be placed between the poles of powerful electro-magnets. Under these conditions, it is reasonable to suppose that the form of the deposit will be modified by the action of the diamagnetism. An Improved Daniell’s Battery.—The Daniell’s battery now commonly used for telegraphic, purposes has held its ground so long against all competitors, that at first sight there would seem to be little scope for inventive power applied to its improvement, yet a considerable improvement has just been made by Mr. Octavius Varley, and it is patented by Messrs. O. and F. Varley, of 11, Poultry, London, E.C. The following are the defects of the ordinary Daniell’s battery :—The sulphate of copper solution diffuses through the porous diaphragm, so that it reaches the zinc plate and covers it with copper; thus the surface of the zinc which should be positive is made negative, the action of the battery is paralysed, and the zinc plate has to be scraped before the proper electrical action is set up once more. Owing to this defe& the full potential of the battery is scarcely ever obtained. Moreover, there is a great waste of the copper salt, for whether ; 4 J 1 J 1871.] Meteorology. 123 the battery be in or out of use, the consumption of the sulphate of copper goes on very nearly the same. When one firm alone sends out £10,000 worth of sulphate of copper per month for telegraphic use at home or abroad, the value of any invention which will prevent waste of this salt in the batteries may very readily be judged. _The improved form of battery is shown in Fig. 31. The great obje& to be achieved is to stop the sulphate of copper, k, from Fic. 31. reaching the zinc plate, z, by diffusion. This is N_ effected by placing the copper salt in a compartment, k, which is watertight at the sides and bottom of the partition R. Thus the strongest part of the sulphate yw of copper solution lies at the bottom of the compart- ment, K, and only the weakest part diffuses over the top of the partition R. The level of the solutions in the ‘battery is represented by w w. Another water- tight partition, B, is so fixed that the electrical current has to pass through the diaphragm of wet sawdust, E. This sawdust is well soaked in sulphate of zinc before it is placed in the cell, therefore, it remains at the bottom of the cell, and does not float on the surface of the liquid. In charging the battery the compartment z is filled with weak sulphate of zinc, and the compartments P and kK with water. The copper plate, k k, has a band of copper, N, attached to it; the electro-deposit of copper begins on the top of this plate, and very slowly spreads downwards. When the battery is not in action, the weak solution of sulphate of copper diffuses into Pp, but when the battery begins working again, the copper is driven back, and the liquid in p becomes once more colourless. Although there are convection currents in the liquid, the faé& that the cell is divided into three. parts prevents these currents from carrying the sulphate of copper to the zinc late. x The result of all this is, that the zinc plates are found to work away till they become as thin as paper, and drop off the connecting band. The battery will go on working for nine or fourteen months when employed in ordinary telegraphic purposes, and it requires no attention beyond charging afresh about once in three months. Some of these batteries have just been ordered by the Government for trial. quae METEOROLOGY. Meteorology was fairly well represented at the British Association. The Report of the Rainfall Committee contained a notice of some experiments carried out at Calne by Colonel Ward, with the object of determining the difference in the amount of rain collected at various heights above the ground. The results of these aré not in accordance with former theories. For instance, we may take the comparison of the quantities collected on the ground, and at a height of 20 feet above it, from which it appears that the difference is, nearly three times as great in winter as in summer, so that the mean annual cor- rection is only applicable to the total yearly fall, separate coefficients being required for the several months. A paper was read by Mr. Charles Chambers, of Colaba Observatory, Bombay, on the cause of the variations of rainfall just alluded to, which he thinks is to be found in electrical ation. He supposes that the globules of water are polarised by induction from the ground, and that according as they coalesce drops are formed. This a@ion would be most rapid close to the ground: it would also be more active over vegetation than over bare earth, and it would be stronger on hills than over plains, owing to the greater electrical tension on the summits. Mr. F. Galton read a very ingenious paper on “ Barometrical Predictions of Weather,” based on a comparison of the continuous records from Falmouth, publishedin the ‘“‘ Quarterly Weather Report of the Meteorological Office.” The. result at which he arrived was, that if we use the ordinary rules given in the text-books for barometrical fluctuations, and the indications of weather they 124 Progress in Physics. (January, afford, ‘“‘judging by the experience of 106 well-marked instances of change occurring at Falmouth during the first quarter of 1869, it is more unwise in the ratio of I0‘o to 7°7 to be guided by the barometer, than to say off-hand that the weather will continue as it has been.” The interpretation to be placed on this apparently paradoxical statement is clearly this. When we consult a barometer, we involuntary interpret its changes with reference to the present appearance of the sky, the direGtion and force of the wind, and ordinary local signs of weather. It is perfectly evident that the use of the barometer by itself could scarcely fail to mislead us. Mr. Laughton read a resumé of his work on “‘ Physical Geography,” noticed in our last number. We did not then explain the agencies to which he attri- butes the cause of atmospherical circulation. His views are concisely stated in the following sentence :— ‘*« All observation shows us that there is not a permanent current (of wind) towards the west, but that there is one towards the east; and although we are unable at present to master all the details of the manner of the motion, the evidence of geographical fact, combined with that of astronomical possibility, justifies us in inclining towards the belief that the motive force for which we are seeking is really the disturbing force of the attraction of the heavenly bodies.” It will be seen that the proofs he adduces for the existence of the celestial influence are not of a very convincing nature. ** The Journal of the Scottish Meteorological Society’ contains a continua- tion of Mr. Buchan’s discussion of the ‘‘ Rainfall of Scotland.” The distri treated of is that of the basins of the Forth and Tay, up to the line of the Grampians. The average fall in the upper valleys of these rivers, in the West of Perthshire, amounts to about go inches per annum, being 20 inches or so more than that colle¢ed at Ettrick Pen, the wettest station in the south- west of Scotland. This result appears to be attributable to the fa@ that the mountains of Ulster drain the south-westerly winds which come to the south of Scotland, while the Perthshire hills receive the air from the open Atlantic. The evidence against the dependence of the amount of rain upon mere height, and in favour of its relation to local conditions, is very clear. Thus, for the region about Loch Katrine, we find that “the absolutely largest average obtained is g1°go inches at Glengyle, which is only 580 feet above the sea. At Loch Dhu, 325 feet high, the quantity is 87°62 inches; whereas, at the Head of Duchray Valley, 1800 feet high, the annual average is only g1°50 inches. Even more striking is a comparison of the rainfall at Leng with that on the west shoulder of Ben Ledi. At Leng, 345 feet in height, the annual quantity is 66°37, whereas on Ben Ledi, at a height of 1800 feet, the amount is only 58°43 inches.” Owing to the war, the foreign periodicals have not come in regularly. We have only received the “ Austrian Journal” upto July15. The papers of most interest in the latest numbers have been those on the climates of the Straits of Magellan and of Bear Island. The first has been extraéted from the «« Anales de la Universidad de Chile,” and great credit is due to Dr. Hann for having rescued it from its comparative oblivion. The observations were taken at Punta Arenas, about the middle of the Straits, by Senor Jorje Schyte. The following table of mean temperatures for the station, compared with those for Dublin and Barnaul, in the corresponding latitude in the Northern Hemis- phere, gives a fair idea of the clynate — Pane Arenas, Dublin, Barnaul, 53°2’ S. 53°3' N. 53°3' N. Winter ne. 20 a eae sk 41°36 Pe o'I4 SPEHAS 5. ale ee AS Ge ae 46°22 se 32°72 WHUMMet | De ee Oa: a 56°84 oe 64°04 AMIE S675. t) tee AA2 2 aA 48°92 a 32°18 Year a Wk vies. AZo oi 48°38 30 32°36 Ranse (sae wee aoe ae 17°60 “i 72°00 a 1871.] Meteorology. 125 The climate is therefore distin@ly “insular,” but cooler than that of these islands. It is also slightly cooler than that of the Falkland Islands. The rainfall is not so heavy as at most of the stations on the West Coast of Patagonia. Inconnection with this statement, Dr. Hann cites Darwin’s remark that the eastern entrance of the Straits is barren and rainless, while at the other extremity the hills are well wooded and watered. We are glad to say that this paper is only the precursor of others on the climate of South America which Dr. Hann promises to give us. The notice of Bear Island is based upon observations made by a Norwegian, Captain Tobiesen, who spent the winter of 1865-6 on the island. The chief point to which we should draw attention is the extreme lateness of the winter ; the coldest month is March, the climate being mainly regulated by the sea surface temperature, which reaches its lowest point in that month. Professor Mohn, Director of the Meteorological Institute of Norway, has made a most valuable contribution to the science of weather in his Storm Atlas, which has just appeared. This contains an account of several storms felt in Norway in the years 1867-8. One of these, that of March 31, 1868, was chiefly felt at the Loffoden Islands, and was in a more northerly locality than any storm which has hitherto been studied. Each period is copiously illustrated by charts. We have first a chart of the entire disturbance, with the paths of the several centres of depression which may have been noticed. For each day four charts are given: one large one, showing the observations of the barometer, wind, and weather, for 8 a.m.; a second smaller one gives the same information for 8 p.m. The other two charts show the variations of the barometer and thermometer respectively for the twenty-four hours succeeding the date of the large chart. Thermometrical readings are not given, except in the form of the variation chart just referred to. On one chart, as a specimen, the tension of aqueous vapour is given. Professor Mohn prefers this mode of representation of moisture to charts of either humidity or the hygrometrical state of the air. The charts show a number of barometrical maxima and minima, each surrounded by isobaric lines. The minima are usually indicative of storms. The form of the innermost curve is generally oval, its major axis lying— E. and W. seven times; N.W. and S.E., twice; N. and S., eleven; N.E, and §.W., five; and indeterminate, seven times. In the cases in which the direction of advance of the minima was clearly marked, it was found to be, on the average, Eg°S, and its mean rate 26 miles per hour. All the storms travelled fastest over the ocean, slackened in speed when crossing Scandinavia, but increased again over Russia. In all cases the easterly component of this motion diminished regularly as the storm advanced from the sea into the interior of the continent. The mean barometrical reading at the centre of the depression was 28°84 in. over the Arctic and Atlantic Oceans ; 28°68 in. over Scandinavia ; and 29°14 in. over Russia. The storms, therefore, increased in violence when passing over Norway, and died out gradually on reaching Russia. The mean direction from which the wind blew during the storms was S.E. on nine occasions; S.W. on sixteen; N.W. on twenty-two; and N.E. on thirteen. Aqueous vapour is always in greatest abundance on the southern side of the path of the centre of depression. It does not, however, travel onwards with the advance of the storm. ‘There appear to be certain distri@s where moisture is constantly present in quantity. These are Portugal, the Mediterranean, South of Sicily, and the Atlantic, off the coast of Ireland. The variation charts show some very interesting facts. Thus, the probable advance of the centre of depression on any day is shown by the next succeeding variation chart. However, on this entire question, which is quite novel, we must look to Professor Mohn to explain his views more thoroughly, for his present statement of them is not at all clear. The second portion of the work is a theoretical account of the origin of storms in general, which, on the whole, agrees with that given by Mr. Buchan, 126 Progress in Physics. [January, as it assumes a spiral motion of the air in the storm; an ascending current at its centre, and a descending counter current outside. The admission is made that the relative influences of the respective causes of these motions cannot be exactly determined. The explanation given of the effect of aqueous vapour is, however, very good. The precipitation of this vapour as rain is acknowledged to be a very active agent in depressing the barometer, and, according to M. Mohn, the direction and rate of advance of the storm area is determined mainly by it. He illustrates this statement by the following instance :— When a storm is advancing across the Atlantic its velocity is great, and its motion is towards the east, owing to the fact that the vapour is transferred over the sea surface so rapidly from the great reservoir of this element, lying to the south of the trajectory of the centre, that it sweeps round in the spiral to the front of the storm, and falls there with a S.E. wind. When the storm reaches Norway the condensation is accelerated by the action of the coast, the barometer at the centre sinks lower, and the rain falls principally with S.W. winds, as mechanical obstacles prevent the free passage of the moist air to the point where it would blow as a S.E. wind. This change in the conditions causes the greatest barometrical variation to be very local, and to be situated to the south-east of the centre. The depression at the centre becomes more serious, the storm slackens in its rate of progress, and begins to move towards the south. When the disturbance has crossed into Russia the supply of vapour is drawn from the Mediterranean. The air which brings it is partially dried in its passage over central Europe; so that by the time it arrives at the storm region we find that the rain falls with westerly winds, the barometer falls fastest to the south of the centre, and the easterly component of the advance of the depression is entirely cancelled. The rain is less in absolute quantity, so that the depression is not ‘“‘ fed” with moisture, and the whole storm gradually disappears. Similar principles are applied to explain the phenomena of the storms of North America, and of tropical cyclones. It is stated that since the opening of the present war in Europe that part of Germany in the vicinity of Frankfort has been almost constantly visited by rain and thunder storms, a most unprecedented thing at this season of the year. In the light of other recorded faéts, the German press has almost unanimously attributed these unusual storms to the firing of cannon and small arms in Alsace and Lorraine. The attention of scientific men is, however,. so well directed to observation of the meteorological events succeeding heavy cannonading that the question of the correlation of artillery discharges with rainfall will eventually be settled. The ‘‘ Ungarische Lloyd,” in an interesting article on this subject, says that the history of the wars of the last eighty years are full of accounts of the great meteorological changes which have followed violent engagements in war. In 1861 Lewis, in an article in Silliman’s «‘ American Journal,” said:—‘‘ In October, 1825, I observed a very plentiful rain immediately after the cannonading which took place in celebrating the © connecting of Lake Erie with the Hudson. I published my observations on this event in 1841, expressing the opinion that the firing of heavy guns produces rain in the neighbourhood. After the first battle in the last war between France, Sardinia, and Austria, there followed such important rains that even small rivers were impassable, and during the great battle of Solferino there broke out such a violent storm that the fighting was interrupted. In July, 1861, M‘Clellan’s troops on the Upper Potomac had four separate engagements on four days, and before the close of each violent rains fell. On the 21st of July Bull Run was fought in Virginia, and on the 22nd rain fell the whole day till late at night. Under the heading, ‘Can we Produce Rain when and where we like ?’ the Cincinnati ‘ Woechtenliche Volksblatt’ for the roth of July, 1862, remarked :—‘ The cannonading (during the war) on the York River and James River, as well as the cannonading of Corinth and on the the Mississippi, were followed by such fearful storms that the land was inundated.’ The Bohemian campaign of 1866 was accompanied during the whole course by violent rains.” 1871.] (127) PROGRESS IN CHEMISTRY, (INCLUDING CHEMICAL SCIENCE, TECHNOLOGY, AND MINERALOGY). CHEMICAL SCIENCE. Tothe list of earth-eating people the Javanese must be reckoned; and Professor C. W. C. Fuchs has given a full account of the edible earth in use by this people. One deposit possessing an intensely red colour, exists in the neighbourhood of Sura Baja, between strata referable to the time of the latest tertiary. This earth is formed into thin cakes, having a diameter of from 1 to ri inches; it is then dried over an open fire, and in this condition is brought into the market. It is perfe&tly smooth to the touch, and is composed of materials in the finest state of subdivision. By a chemical analysis it is found not to contain the slightest trace of an organic substance. It is apparent that the earth consists of a clay rich in iron, in which is still retained small quantities yet undecomposed, of the minerals from which it derived its origin. Upon rubbing it, not the slightest grittiness is perceptible, and on being moistened with water it forms a smooth and unctuous mass. The enjoyment derived from eating it seems to reside in the similarity of the sensations it produces with those derived from the eating of fatty substances. In many parts of Wirtemburg the quarrymen have the habit of eating the smooth, unctuous clay which collects in the fissures of the rocks. The term ‘‘ Mondschmalz,” which they apply to it, would seem to refer to the enjoyment they experience in the process of eating. Dr. Hofmann has discovered a most delicate test for chloroform, based upon the faé that, when chloroform is mixed with aniline and an alcoholic solution of caustic soda, a very strong reaction takes place, and isonitrile is generated, which is readily recognised by its peculiarly characteristic smell; this reaction is so delicate that, when 1 part of chloroform is mixed with from 5000 to 6000 parts of alcohol, the first-named substance is readily detected. Professor Seely has made the discovery that anhydrous liquid ammonia has a solvent power upon certain metals, and he has actually succeeded in obtaining a solution of sodium in liquid ammonia. This solution presents all the physical characteristics of a true solution. On evaporation, the sodium is gradually restored to the metallic state in the same continuous manner in which the solution has been affected. The colour of the solution is a very intense blue, of high tinctorial power. A very simple and powerful method of resolving minerals in analysis has been devised by Dr. Schonn. A steel crucible is heated over a lamp; into this is projected a few pieces of metallic sodium, and afterwards the finely-divided and dry mineral is added. The crucible is then covered and heated to redness. As soon as the the reaction is finished the contents of the crucible are allowed to cool, and water is cautiously added, sufficient for the purpose of filtration. The fused mass is then thrown upon a filter and thoroughly washed. In the filtrate will be found the eleCtro-negative constituents of the mineral combined with the sodium, such as sulphur, cyanogen, chlorine, chromic acid, silica, molybdic and tungstic acids, and such oxides as are soluble in soda-lye. On the filter will be found the metals and their oxides, also the lower oxides of titanium, molybdenum, tungsten, and possibly silica and alumina. The contents of the filter and the solution in the filtrate can be further treated according’to the order of analysis. In this way all minerals can be readily tesolved, and their constituents determined either qualitatively or quantitatively. In a paper on organic matter in water, Mr. C. Heisch indicates a very simple test for the presence in water of organic matter arising from sewage contamination, which consists in adding ten grains of pure loaf sugar to six ounces of the suspected water, and setting the bottle aside for a few days in a warm place exposed to light, when, in the event of a sensible quantity of this 128 Progress in Chemistry. |January, unwholesome form of organic matter being present, the germs become developed with generation of small spherical cells and strings, which are easily discoverable under the microscope, and, in extreme cases, cause a general turbidity, with production of a butyric odour. Filtration through the finest quality of Swedish paper was found to be ineffectual in keeping back this kind of impurity; but treatment with animal charcoal and subsequent filtration proved much more efficacious in removing this source of contamination. Recent events on the Continent have rendered all subjects connected with the economy of food or of counteracting the effects of insufficient food of the highest importance. A French experimenter, M. Rabuteau, suggests that a man may live for several months, and keep active, strong, and healthy, by consuming daily 150 grms. of a mixture (dry) of powdered cocoa, 1000 grms. ; infusion of coffee, 500; infusion of tea, 200; sugar, 500 grms. The two infusions, as strong as can be made, to be evaporated to dryness previous to being mixed with the rest of the substances, The whole weight of this 2220 grms. would be only about 1600, and would be sufficient food for ten - days; when taken it is to be mixed with some boiling water. The author states that it is highly agreeable, he having purposely experimented with this mixture upon himself while abstaining from other food. Speaking of the great tinctorial power of some of the aniline dyes, Dr. Hofmann quotes the following :—The solution of a salt of rosaniline, mixed with a few drops of acetic acid, and so diluted with water as to have 1 part of the rosaniline salt to 1,000,000 of water (1 milligrm. to 1 litre of liquid) is deeply carmine-coloured, and yields a fluid capable of dyeing silk thread, previously moistened with dilute acetic acid. When the coloured liquid is diluted with water, so that 25,000,000 parts of that liquid are present (1-25th of a milligrm. of the salt to the litre), the liquid is yet distin&ly cofoured ; and silk,immersed in this bath for a quarter of an hour, is dyed a pale rose-colour when removed from the liquid. Even 1 part of the rosaniline salt in 100,000,000 parts of water is visible, if the layer of liquid seen through is about half a metre thick. Dr. Klein, a pupil and collaborator of Professor Jacobi, of St. Petersburg, states that the iron obtained by electrolysis is not, as has been often thought, the pure metal, but, on the contrary, a compound of iron and hydrogen, which, when heated to redness, gives off an enormous amount of that gas, and becomes, while greatly increasing in bulk, a silver-white, very soft, dudtile, and malleable metal, which decomposes water readily below its boiling-point and oxidises most rapidly. A lengthy memoir of a series of experiments on the venom of the Scorpio occitanus, has recently been published by Dr. Jousset. The author draws, from his experiments, the following ‘conclusions:—The venom of the Scorpio occitanus acts direG@ly and solely upon the red blood globules. This action consists in withdrawing from the globules their property of gliding over each other. By losing this property, the blood globules become glued together, and, by thus becoming an adhesive mass, obstruct the circulation of blood in the capillary portion of the vascular system, thereby causing a stasis which is altogether incompatible with the proper conditions of life. Since the ation of — the scorpion’s venom is purely chemical, and a certain quantity of it (the venom) is required for exerting its action, it essentially differs from virus, which — acts as a ferment. - Dr. W. Wenzell finds that a solution of 1 grain of permanganate of potash in 2000 germs. of sulphuric acid is, far excellence, the test for the successful demonstration of traces of strychnine. The limit of positive recognition by © the bichromate of potash and sulphuric acid test may be placed at 1-100,000th, ~ that of the chromic acid test at 1-600,oooth, and that of the permanganate at 1-900,000th. The discovery of this use of permanganate is due to Dr. Guy, of London. ‘ 1871.] Technology. 129 TECHNOLOGY. To separate or distinguish the fibres of silk, wool, cotton, jute, &c., when interwoven or composing the structure of mixed fabrics, Mr. Spiller employs concentrated hydrochloric acid, which has the property of dissolving silk immediately and completely, without appreciably affecting any woollen or lignine fibres (cotton, linen, jute, &c.) with which the silk may have been interwoven. Having submitted the material to the action of hydrochloric acid and noted any indications of rupture or solution of the fibres, the residual fabric or loose fila- ments may be washed and collected, and will usually be destitute of colour. The presence or absence of wool in that portion of the fabric which resists the attack of hydrochloric acid is then determined. A warm aqueous solution of picric acid instantly imparts a full yellow tint to wool, but does not in the least affect cotton, linen, jute, or China grass, so that it is only necessary toimmerse the fabric or fibres in the dye, wring out, and wash well with water in order to remove the adhering yellow solution, and note any indications of the existence of wool. In the examination of ribbons and some other stiffened goods it is often necessary to immerse them for a few minutes in boiling water, to dissolve out the starch or size prior to applying the hydrochloric acid test, for, by this simple expedient, the results are rendered much more decisive. A new sulphur deposit has been discovered in the Island of Saba, a Nether- lands’ possession; it was accidentally discovered by an enterprising New Yorker, who visited the island in search of health. With the aid of some of the natives, he succeeded in quarrying about two sloop-loads of the crude mineral, which, on being brought to New York, was found to yield, on an average, rather over 60 per cent of sulphur, while the Sicily mineral only yields about 30 percent. The deposit is, considering the small size of the island, very extensive, and will be of great value for the manufacturing interests of the United States, being distant only about 1500 miles from New York. When glue, in thick solution, is mixed with tungstate of soda, and hydro- chloric acid is added, there is thrown down a compound of tungstic acid and glue, which, at from 30° to 40° C. is so elastic as to admit of being drawn out into very thin sheets. On cooling, the mass becomes solid and brittle; but, on being heated, it becomes again soft and plastic. This material has been suc- cessfully employed, instead of albumen, in calico-printing, in order to fix the aniline colours upon cotton. M. Méne has effetted some considerable improvements in the treatment of wood for paper manufacture. The wood, previously reduced to the state of shavings or sawdust, is placed for a time in water, and is left there to rest. The rotting in water has the effect of disintegrating and partly decomposing the nitrogenous matter of the wood, and the fibre is also afterwards more readily bleached, not becoming yellow by the use of chlorine, as is the case where these matters have been left in the wood. The rotted wood is tho- roughly washed with boiling water and steamed, and next treated with an alkali. Experiments with gun-cotton have recently been made at Chatham on an unprecedented scale of magnitude, and in connection witha system of electric-torpedo defence. Charges of 432 lbs. weight Hie. oo have, upon two separate occasions, been fired by Messrs. Abel and Brown, with results which are stated in the official reports to be of the most decisive character, and such as would un- doubtedly have sent to the bottom the largest iron-clad vessel in the world, had she been within range. There are many locations in which the Bunsen filter pump cannot be employed on account of a deficiency in the water supply. For such cases a plan has been devised by Dr. Walz, of New York, which has been proved in pradice to be efficient. | The accompanying cut shows the outline section of the most important part of the apparatus. a is a tube supplied with steam from a flask or boiler; E is conne@ed with the ex- haust of the filter. By the action of the steam jet identical with that known as the “ exhaust” in a locomotive, a vacuum VOL. VIII. (0.S.)—VOL. I. (N.S.) S 130 Progress in Chemistry. [January, is produced in BC D. By sliding the tube, a, back and forward in the cork, B, an adjustment can be given to the outlet within D, so as to secure the best effet. The conditions of best effect here are identical with those in the inner nozzle of the Giffard injector when it is starting its water supply from a lower level, and no doubt the proportions found most efficient in that instrument will prove also in this. According to Dr. Wiederhold, genuine Chinese lacquer-work is done over tin-foil, and consists of a mixture of 2 parts of copal and 1 of shellac, melted together. When fluid, there are added 2 parts of boiled linseed oil; and, after the vessel containing this mixture has been taken from the fire, there are gradually added 10 parts of oil of turpentine. If colour is required, gummi- gutta, dissolved in oil of turpentine, yields yellow, and dragon’s blood, dissolved in the same liquid, yields red. A plastic material of great resistance, suitable for a variety of uses, is pre- pared by M. Rost, as follows :—He mixes litharge and glycerine, so that they may form acreamy liquid. The mixture becomes, in a short time, a hard, homogeneous mass, which readily adheres to metals, resists the action of water and steam, and a temperature of 275° C. In many instances, this paste is preferable to red-lead cement; and this glycerine-litharge paste may be even used, when in very fluid state, for galvano-plastic copying, since the material preserves even fine engraved lines. Dr. Béttger prepares a glue which stands moisture without softening, by dissolving in about 8 fluid ounces of strong methylated spirit } an ounce of sandarac and mastic, and next adding 3 an ounce of turpentine. This solution is then added to a hot, thick solution of glue to which isinglass has been added, and is next filtered, while hot, through cloth or a good sieve. MINERALOGY. It must be confessed that when the discovery of diamonds in South Africa was first announced in this country, some three or four years ago, there was a tendency among many men of science to indulge in a little incredulity as to the genuineness of the reputed discovery. But, whatever may have been the doubts which were conscientiously entertained at that time, they have assuredly been long since dispelled by the glowing accounts which have since reached us—substantiated as those accounts have been by the arrival of larger consign- ments of the veritable gems, especially by the Cape Mails during the past quarter. Whilst the majority of these stones are, as might be expected, of only small size, there are, nevertheless, an unusually large number of them which exceed the average weight. One South-African diamond weighs 56 carats, and a second stone—now in the hands of Messrs. Hunt and Roskell* —reaches 83 carats, while a correspondent of ‘‘ The Times”+ has recently alluded to a fine octahedron of not less than 107 carats. Of course it is not to be expected that all the stones are of fine quality, and, indeed, it appears that a large proportion of the Cape diamonds are very defective. As to the conditions under which the gems are found in these new distrits—a subje& of the first importance to all who purpose adventuring forth to the diamond-fields —it appears that they are commonly found, not in the beds of rivers as is elsewhere generally the case, but rather on the summits or on the slopes of the little kopjies or hillocks, where they are sparsely disseminated amid detrital accumulations, which consist of water-worn pebbles of quartz, agate, cornelian, jasper, iron-ore, itacolumite, and basalt; while in many places they occur in a ferruginous gravel associated with a conglomeratic rock. We understand that many practical men at the diggings believe that the distribution of the diamonds bears some relation to the occurrence of certain trap rocks in the distri, and even suspect that. in or near such rocks they may find the original matrix of the gem. Without admitting for a moment that the enigma of the genesis of the diamond is yet completely solved, it may be well to * * Journ. of the Soc. of Arts, Nov. 25, 1870. + Nov. 11, 1870. 1871.] Mineralogy. 131 remember that we are in possession of a large body of evidence tending to show that the diamond is probably of vegetable origin, or has at least been formed by the wet way, and that, therefore, its occurrence is not to be expected in an eruptive rock, although the presence in such a rock may have influenced its development. It may not be amiss to direct the attention of diamond-seekers at the Cape to the probable occurrence of the substances known as bort and carbonado in association with the true diamonds. These minerals are, from their unattractive appearance, likely to be overlooked by those who are absorbed in looking for the more precious gem, and yet they possess, in consequence of their extreme hardness, a very high value for polishing purposes. The black metallic-looking carbonado accompanies the diamond in Brazil, where it was entirely overlooked until a comparatively recent date, and we believe that it has already been found in South Africa. Whatever may be the future prospects of the South-African diamonds-fields, it is certain that we must henceforth register in our mineralogical text-books such parts of the valley of the Vaal as Pniel and Hebron as important diamond-bearing localities. In New South Wales the search for diamonds has also been prosecuted with some measure of success, and according to Mr. John Hunt,* who has acted as Manager of the Australian Diamond Mining Company’s Works, there have hitherto been found in the colony about 5500 diamonds, averaging one grain each. He believes that an excellent clue to the presence of diamonds, there and elsewhere, is afforded by the presence of a certain green mineral containing phosphate of iron. The diamonds of New South Wales are found, accom- panying gold, in the alluvial drifts, and especially in the neighbourhood of basaltic rocks. Some time ago we hinted that diamonds had been reported from Bohemia. The report was circulated in many of the German and Bohemian journals, but according to Professor Zepharovich,+ it rests upon a very insecure basis. Indeed, it appears that only a single stone has been found, and this under conditions far from satisfactory. As is well known, the pyropes, or “garnets,” found in the sands of some of the Bohemian rivers are extensively cut and polished for the purposes of the jeweller; and it was among a number of these stones at the polishing-works of Dlaschkowitz that the diamond in question was found. Thata diamond has been discovered among Bohemian garnets is, therefore, certainly a fact; but that it was derived from the same deposit with the garnets is, at present, merely an assumption. When we remember that diamonds are in daily use in the workshop for the purpose of boring the garnets, a suspicion arises that after all the so-called ‘‘ Bohemian diamond” may be merely a stray stone from the lapidary’s stock. At least it behoves us to be silent upon the subject until we shall hear that diamonds have a@ually been found in the garnet-bearing sands. More than twenty years ago the Italian mineralogist, Professor Scacchi, described a new arsenical sulphide from the solfatara in the Phlegrcean fields, where it occurs in the form of minute orthorhombic crystals difficult of measurement, but still sufficiently perfe& to exhibit, in different specimens, two distiné sets of axial relations, whence the mineral received the name of Dimorphine. Dr. Kenngott has recently made some observations on the crystalline forms of this so-called species, and finds that not only are the two types of form closely related to each other, but that-they stand extremely near to the crystalline forms of orpiment. Dimorphine appears, therefore, to be crystallographically nothing more than orpiment, but while orpiment contains As2S3, it appeared from Scacchi’s imperfect examination that dimorphine had the composition of As,S3. Nevertheless, the specific gravity and the colour of the two minerals are almost identical, and, on the whole, Kenngott is disposed to lay aside Scacchi’s formula, and to believe that dimorphine must be united with the species orpiment. * Mining Journal, Nov. 12, 1870. + Poggendorff's Annalen, 1870, No. 8. : j t Leonhard and Bronn’s Neues Jarbuch fiir Mineralogie, 1870, Heft 5, p. 537. 132 Progress in Chemistry. (January, Some simple experiments of considerable interest to the mineralogist have been made by Herr Credner, in Kolbe’s laboratory at Liepzig,* with the view of determining what influence is exerted upon the crystalline form of carbonate of lime by the addition of certain substances to the solution from which it crystallises. It is generally believed that aragonite is deposited at high and calcite at low temperatures, but Credner finds that aragonite may be obtained from a cold solution of bicarbonate of lime, if a small quantity of bicarbonate of strontia be present; and that on adding very slowly the strontium’ bicarbonate to the lime solution, the rhombohedra of calcite which are deposited are accompanied by short acicular crystals of aragonite. The dimorphism of calcic carbonate is seen, therefore, to depend not only on temperature, but also on the presence of foreign substances in the mother-liquor. Again, while calc-spar crystallises in rhombohedra from a pure solution, these simple forms are much modified by the presence of a small proportion of nitrate or carbonate of lead, or of silicate of potash or of soda. A specimen of obsidian, or volcanic glass, from Hecla, in the mineralogical collection of Zurich has recently been made the subje& of careful microscopic examination by Professor Kenngott.t These observations may be said to supplement those of Zirkel on a like subje&. Kenngott’s specimen exhibits a brown vitreous base, in which may be detected a number of dark-coloured concretions, each surrounded by a pale ring formed of yellow acicular crystals arranged in a radiate form, whilst certain other smaller concretions are surrounded by fine black hair-like bodies. A few minute crystals of belonite were observable, and throughout the whole base were abundantly strewn certain small black particles, which are probably crystals of magnesian mica. Two parallel layers run across the specimen, and exhibit oblique striation; the striz may be resolved by a high power into a system of markings, the ultimate lines being merely rows of points which are really small crystals. The joint work of Professor Maskelyne and Dr. Flight contains much that is valuable, both chemically and crystallographically; but as it has been submitted to the Chemical Society, we need do no more in this place than call the attention of the crystallographer to the interesting example of hemi- morphism—not hemihedrism—presented by the crystals of cronstedtite which have recently been found in Cornwall. A number of newly-described species and varieties, as usual, call for attention, but must be noticed as briefly as possible. Rzonite is the name of a bismuthic variety of fahl-ore from near Cremenz, in the Einfischthal, in Switzerland, where it is worked for the sake of the bismuth which it contains and which amounts to upwards of 13 per cent.{ A manganese ore containing lithium was discovered some time ago by Herr Frenzel, and has been lately described under the name of Lithiophorite.|| It occurs in some of the iron-lodes of the Erzgebirge, in Saxony, and is merely a produé of alteration, derived probably from psilomelane. Professor C. U. Shepard calls attention to some new minerals from the guano deposits in the Guanape Islands.§ One of these, termed Guanapite, contains sulphate of potash with sulphate and oxalate of ammonia; whilst a second species, named Guanoxalite, contains sulphate of potash, oxalate of ammonia, and water. Ambrosite is Shepard’s name fora resin resembling amber, and occurring in the phosphatic formation near Charlestown, South Carolina. In compliment to the Tyrolese geologist, Herr Trinker, a new mineral resin, allied to Professor Church’s Tasmanite, has been described by Tschermak under the name of Trinkerite.§ It occurs in red or brown masses in the lignite of the fresh-water beds near Carpano in Istria, and has the following percentage composition :—Carbon, 81'1; hydrogen, 11-2; sulphur, 4°7; and oxygen, 3. Uvanotile is Boricky’s name for a new mineral * Leonhard’s Jahrbuch, 1870, p. 603. + Ibid., 1870, p. 529. + Ibid., 1870, p. 590. | Journ. f. Prakt. Chemie, 1870; Bd.2(N.S.), p. 203. § “The Rural Californian,” Silliman’s Journal, Sept., 1870, p. 273. { Jahrb. d. Geol. Reichsanstalt, xx., p. 279. 1871.] Mineralogy. 133 from Wolsendorf, in Bavaria,* where it occurs in the form of yellow acicular erystals in druses of quartz encrusting fluor-spar. The crystals, which belong to the rhombic system, contain—Silica, 13°781; phosphoric acid, 0448; peroxide of uranium, 16°752; alumina and ferric oxide, 0°511; lime, 5-273 ; and water, 12°666. Excellent information on the mines and minerals of Elba—an island to which we are indebted for those wonderful specimens of specular iron-ore, iron-pyrites, and lievrite, which grace the cabinet of every mineralogist,—will be found in Von Rath’s recently-published mineralogico-geological essay on that island.t Gustav Rose has shown} that in iron-pyrites and cobaltine a close relation exists between the hemihedral forms of the crystal and their thermo-electric properties. The same author announces the discovery of zircon in the hyper- sthenite of the Radauthal inthe Hartz.|| Dr. Scharff has published a crystallo- graphic paper in which he seeks to determine what influence twin-growth exerts upon crystals of calcite. § So full of interest are the volcanic rocks which occur in the neighbourhood of the Laacher See, in the Eifel, that they have often courted investigation by the mineralogist and geologist. We need not, therefore, do more than call attention to a series of papers in course of publication by Herr Dressel, whose long residence at the Abbey of Laach has given him more than usually good means of observation. His first contribution deals with the trachyte of Laach. 4 The Townshend $ewels——Much scientific as well as artistic interest centres about many of the minerals which have been used for purposes of ornament. The study of the intruding substances and the cavities often occurring in quartz, ruby, and topaz, has led to the discovery of many singular fats, and has partially lifted the veil which shrouds from curious eyes the origin of some of the most beautiful products of the earth. So also the crystalline forms and optical properties of precious stones, together with the action of heat and other forces upon them, have afforded ample and profitable materials of research for the mathematician and the physicist. Thus it would be easy to vindicate the claims on scientific consideration which jewels possess. Were we to travel for a moment out of the path which we intend to follow in the present notice, and to speak of the artistic qualities of precious stones, we should have a rather difficult task to accomplish, for strange to say, it has become usual, amongst a certain clique of artists and connoisseurs, to depreciate their beauty. Professor Ruskin,** for example, talks of the colours of gems as “ entirely common and vulgar;” he calls the green of the emerald as “vulgar as house- painting,” and states (what is absolutely incorre&t) that ‘‘no diamond shows colour so pure as a dewdrop.” ‘ The ruby,” he adds, ‘is like the pink of an ill-dyed and half-washed-out print compared to the dianthus.” Other writers on art, ignorant of those wondrous properties of jewels which are developed only by judicious cutting, would not allow a specimen to be facetted, but simply rounded and polished in the way known as en cabochon. Our present purpose, however, is not to offer a logical justification of the fondness for precious stones, which most people exhibit to some degree, but to dire the attention of our readers to the superb suite of specimens which has been recently bequeathed to the nation by the late Rev. C. H. Townshend. The colleGtion is to be seen in the South Kensington Museum, and is, or was recently, in one of the picture galleries. A catalogue++ of the specimens has been published under the auspices of the Science and Art Department, but, * Leonhard’s Jahrbuch, 1870, p. 780. + Zeitsch. d. Deutsch. Geolog. Gessell, xxii., 1870, p. 591. ~ Monatsbr. d. k. Akad. d. Wissensch., Berlin, 1870. | Zeitsch. d. Deutsch. Geolog. Gessell, xxii., 1870, p. 754. § Leonhard's Jahrbuch, 1870, p. 542. {1 Ibid., p. 559. ** Ruskin’s Lectures on Art, pp. 176 and 177. (1870). ++ Catalogue of Gems and Precious Stones [Townshend Bequest], by J. Tennant. (1870). 134 Progress in Chenustry. [January, unfortunately, it is in many points an inadequate’ production: for ease of reference it will, however, be expedient to follow the order in which the speci- mens are therein described. A fine large crystal of diamond (No. 1172) affords an example of the pecu- liarly brilliant lustre which distinguishes even the natural surfaces of this stone, and permits any one who appreciates its character to single out a rough diamond from all other stones. The specific gravity of the diamond (3°53) does not enable us to distinguish it from glass or white topaz with certainty, though it separates it from white quartz, which is only 2°65, and white beryl, which is only 2°71. There is a black diamond (No. 1173) in the colleGion, which displays on its facets the characteristic lustre of the stone. A colourless diamond of pure water, and about ;5, of an inch across, is a splendid brilliant from the Hope collection. A lustrous yellow diamond of the same size should also be noticed. Of other coloured diamonds there are two green specimens, one of a pale blue hue, one of a curious and very rare puce tint. It will not be necessary to dwell upon the peculiarities of any of the many forms of silica represented in the collection. Almost all the ordinary and most of the rare varieties may be here seen mounted in rings, and in some cases set off by borders of diamonds. One amethyst (1187) is remarkable for containing several cavities partially filled with fluid. Some of the translucent specimens known as cat’s-eye, of a yellow or brown colour, are good examples of the peculiar “ chatoyant ” effect produced by regularly disposed asbestos filaments penetrating the quartz. Several of the specimens catalogued under the heading Silica belong, however, to far more récherché species. One, for instance (No. 1188), is probably a pink topaz, and not an amethyst; another, called Burnt Quartz (No. 1194), appears to be a splendid chrysoberyl, the dispersive power of the stone being far too high for silica. Burnt quartz is the name given (after strong heating) to a dark variety of rock crystal from Portugal and Brazil, which assumes, after having been submitted to a high temperature, a sherry-brown or red colour. Of opals there are more than a dozen in the Townshend collection ; many of them exhibiting the most superb play of prismatic colours. One is pale grey, and shows a fine blue iridescence. The sapphires and rubies include a series of fine specimens of the highly- prized deep velvet blue, and the pigeons’-blood red colours. There are also some violet and salmon-coloured corundums of great rarity and beauty. A golden-yellow one, of great brilliancy (No. 1312) is included with the topazes. The star-rubies and star-stones are well represented. These stones somewhat resemble the cat’s-eye, but they show a six-rayed star, which is best seen when the gem, cut across its principal axis, and left with its top en cabochon, or rounded, is viewed in sunlight or in the focus of a-condensing lens. In the case of these star stones, the internal reflection is due, not to intruding sub- stances, but the mode in which the crystal has been built up of symmetrically disposed but'not perfe@tly regular layers. The turquoise comes next in order. The true turquoise is a phosphate and hydrate of aluminium coloured by a little phosphate of copper. The false, or bone turquoise, is merely fossil ivory tinted with phosphate of iron, not phos- phate of copper, as stated in the catalogue. Several of the most beautiful varieties of garnet are seen to perfection in the Townshend series. Two of the specimens (1306, 1307) are wrongly labelled “‘jacynth,” and included under the heading Zircon in the catalogue. One of the so-called garnets, of an amethystine colour, seems likely to belong to another species. A fine inscribed emerald, from the celebrated collection of the late H. P. Hope, is the first beryl in the list. It is of rich colour, and nearly % inch by # inch in dimensions. Another stone (No. 1284), though smaller, is a still finer speci- men, faultless in cutting, shape, and colour, and almost half an inch across. The aquamarines in the colleGion are of immense size and rich hues. One of them presents almost the exact tint of the more valuable blue topaz. Nine specimens are catalogued as chrysolites, but at least four of these are incorre@ly assigned to this species. Nos. 1297 and 1304 are chrysoberyls, while 1304 is a zircon of the variety known as jargoon. 1871.] Mining. 135 The white topaz is not well represented in the collection, and there is great confusion amongst the coloured varieties of this stone. No. 1309 is much more like a spinel than a topaz, while No. 1312 is a splendid yellow sapphire. No. 1318 seems only quartz. Of the five stones labelled as tourmalines, one, No. 1322, is certainly a jargoon. The green tourmaline (Nos. 1321, 1323) is a beautiful but not brilliant stone. A peculiar interest attaches to this species, owing to its optical cha- tacters. It is a striking instance of dichroism, the rich grass-green specimens being perfectly opaque when viewed along instead of across the principal axis of the crystal. Among the spinels is one of an indigo-blue colour (No. 1325), and two fine pink-coloured specimens. There is a splendid suite of chrysoberyls, although some of them are incorre@ly included under quartz and chrysolite. The precious cat’s-eye, or cymophane, is a variety of chrysoberyl. Its opalescence is due to its intimate structure, and only appears when the light is incident at a particular angle. The line of light should be straight and clear as silver wire, and shows to the best advantage when the stone is of a clear green tint. We have not space to-record the peculiarities of the remaining species represented in the Townshend gift. There are moonstones and sunstones, with examples of labradorite, kyanite, and pyrite, all gorgeously mounted in gold coronet rings, and in many instances set off by rows of diamonds. We have merely noticed the existence of this very interesting and valuable collection in the hope that it may receive that attention at the hands, both of artists and mineralogists, which it deserves. The names assigned to about twenty of the specimens should be revised, and then we should possess in London three fine suites of authentic precious stones, from which their characteristics might be readily learnt. The other two public collections are in the British Museum and the Geological Museum of Jermyn Street. It is greatly to be desired that the specific gravity, hardness, crystalline system, and refractive and dispersive power should be noted on the label of each specimen. inn lale (G- PROGRESS IN MECHANICS, (IncLuDInNG Mininc, METALLURGY, AND ENGINEERING). MINING. ALTHOUGH the Statistical Returns which for many years past have issued with great regularity from the Mining Record Office, under thé direGion of Mr. Robert Hunt, F.R.S., have this year been delayed in publication, owing to the illness of their respected editor, they have appeared sufficiently early to enable us to publish in this number our usual summary of their contents. The following statement shows the quantity and value of the several minerals raised in the United Kingdom during the year 1869* :— Tons. Lites Coal .. oe tech rvek Miual 107,427,557 26,856,882+ HER OTRIMON tcc en ines hate) keoslt ate sinh, (aSpn Loi 11,508,525 35732,560 PAMOGE ait ros a,c notes | Bey tie) / leva 14,725 1,027,805 Copper ore PUR RS SNE gE lence 129,953 519,912 PRG AORONE: verte cas? ever ate 96,866 I,189,030 Zinc ore 15,533 49,366 Iron pyrites 75,948 41,023 * “Mineral Statistics of the United Kingdom for 1869.” By Robert Hunt, F.R.S., Keeper of the Mining Records. + Calculated before any charges for movement are added. 136 Progress in Mechanics. [January, Tons. te APSenic ‘OFESi 41," eee ee ee 25505) see 11,464 Gossans, ochres, &c. (returned) .. .. FOO. ae 943 i. (estimated) aya aie 5,000 ns 4,000 Wolfram and tunsgate ofsoda .. .. 2 ee 323 WMASAneSC seen aoe eee ete 15550 ee 7,807 BatyteS.© so ceease both mire ate ee S007 ee 3,415 Clays, fine and fire (estimated) .. .. 1,200,000 .. 450,000 Earthy minerals, various (estimated).. = 34 670,000 Sale AS NOME ee ee ee Pee ae 1,250,000 .. 687,500 Total value of the minerals produced in the United Kinedom dase <.2)