P' being the point where the perpendicular to the plane, henceforth to be called its normal, meets it: and the expressions previously obtained for an edge, a zone line, or a zone, are equally applicable when the axes are taken as oblique. The next step to be taken is to extend this idea of normals drawn to all the planes of a crystal to that of their continuation until they meet the surface of a sphere which is supposed to be described round the origin of the axial system as its centre. The faces of the crystal may be conceived as drawn so as to be tangent planes to such a sphere; or, again, we may suppose their normals to be continued onwards through the planes until they penetrate the sphere's surface. In either case, the points at which they meet that surface will be termed the poles of those planes. It is evident that by this means the situation of a plane is known when we know that of its pole upon the sphere. Any great circle of the sphere passing through a pair or a Beyond P' again, let Q become Q'; and now the ratio Q'P P P' series of such poles will offer, in the arcs intercepted The lecturer next made a digression into the subject of the different methods employed for the graphic representation of crystals; and, after alluding to the usual orthographic representation of their edges in the pictures met with in crystallographic treatises, he proceeded to consider the simple and comprehensive method afforded by projecting their poles in what is termed the stereographic projection. The eye, being supposed to look into the sphere from a point on its surface, sees the poles distributed on the hemisphere opposite to that point, as though depicted on a screen passing through the centre of the sphere, and bounded by the great circle of which the position of the eye would be the pole. All great circles of that opposite hemisphere are now projected on the plane dividing the sphere as circular arcs, except such as pass through the pole opposite to the eye, which are presented as straight lines passing through the centre of the circle of projection. These points were illustrated by a working model, as were also the means of measuring arcs on a projected circle by drawing lines from its projected pole to the circle of projection. Methods for finding the centres for these projected arcs were also illustrated by the model in question. The lecturer finally dwelt on the great importance to approximates to 1+0. If now we consider the ratios of the parts into which the line is divided internally to P P' by Q, and externally by Q', these ratios— QP Q P and Q' P of Q', there may also be found one corresponding position offer us a series of values, among which, for every position of Q, such that =1 Q' P and this is what has long been known as the harmonic Reckoning magnitudes as positive in the direction P P', = or : =-I. This equality of the ratios, however, is only a particular case of that more general proportion with which we have to deal. Mr. Maskelyne then proceeded to state some of the more general properties presented by what have been called anharmonic ratios by M. Chasles. Thus, if four rays are drawn through a point, and any line cut these In reverting to the subject discussed in the last lecture, Mr. Maskelyne showed that, if two of the rays in a sheaf of four be perpendicular to each other, and one of them bisect the angle between the remaining two, the ratios of the sines of their angles become harmonic. a continuous chain of reasoning, will at least have become accustomed to the ideas and the terms expressing them own; and with this preparation we can enter at once on the which even the exoteric crystallographer has to make his subject of crystal symmetry. (To be continued.) ON THE WOOL. By E. SCHULZE and A. URICH. Reverting from this digression to the subject of a zone, and considering the radii of a sphere drawn to a series of poles on the same zone circle, which represent, therefore, COMPOSITION OF THE FATTY MATTER OF the normals of the planes of that zone, he stated, as one of the many contributions of Professor Miller to crystallographic science, that he had shown that the anharmonic ratios of the sines of the angles between any four such normals are identical in value with the corresponding ratios of the determinants of the symbols for the four planes. Consequently, we may say that the anharmonic ratios yielded by the normals of four tantozonal planes, and, therefore, also by the planes themselves, must in a crystal be rational, since the symbols of the planes involve only rational numbers. This is a result of the greatest importance, as limiting the kinds of symmetry that are possible in crystals, as will be hereafter seen. Another important result of this great principle-a principle which, in fact, is only another way of stating the fundamental crystallographic law-is, that we are hereby enabled to deduce relations of great practical value between the angular inclinations and the symbols of four tantozonal planes; the expressions relating to three planes only in a zone not being capable of affording this result. From what was said at the opening of this lecture, it now becomes clear, as an illustration of this point, that if one plane in a zone is equally inclined on two other planes in it (Fig. 6), a plane perpendicular to the first must be a possible plane of the zone, since the normals of the four planes form a harmonic sheaf of lines, and vice versa. Proceeding to discuss the conditions requisite for three successive angles between the planes of a crystal zone being equal, Mr. Maskelyne showed that we come to an expression that limits the values of this angle & to such in which cos. is rational, and this can be further shown to be true only in cases where & has one of the four values, 90°, 45°, 60°, or 30°. Future lectures, which will deal with the subject of crystal symmetry and the actual forms and systems that crystals may present, will be mainly concerned with the results that IN a former communication, one of us has shown that, along with free cholesterin, compound ethers of cholesterin and of isocholesterin are found in the grease of wool. The question as to the composition of wool-fat could not be fully solved with the data which we formerly obtained. From the elementary composition of the crude mixture of the wool-grease alcohols, it appeared that, in addition to cholesterin and isocholesterin, another alcohol, poorer in carbon (or a number of such) must be present. We have, therefore, examined two fresh kinds of wool-grease. The one, which we shall designate as b, was obtained from the raw wool of North German sheep, by extraction with ether; the other, c, was obtained in the same manner from the raw wool of a Swiss mountain sheep. From that portion of both samples which was readily soluble in alcohol it was easy to separate pure cholesterin, and it was proved that this compound was chiefly present in the free condition. The portion of b not readily soluble in alcohol yielded, when decomposed with alcoholic potash along with potash soaps, a mixture of wool-fat alcohols, resembling the product obtained from the wool-grease formerly examined. Along with cholesterin was found isocholesterin, apparently in equal quantity. It was separated from cholesterin by the method which we previously employed. Isocholesterin was also found in c, but in a relativ small proportion. When, therefore, the mixture of grease alcohols which separated from the sparingly s portion of the sample had been dissolved in an exc ss of spirits of wine, at first only cholesterin crystallised out o the solution on cooling, without an admixture of isocholesterin. The latter was subsequently deposited from the mother-liquor. Our attention was mainly concentrated upon obtaining the alcohols poorer in carbon. From the results of our previous researches, it seemed that this substance was only present in wool-grease in a small quantity, for it had not been possible to obtain, from the mixture of benzoic ethers, besides benzoic cholesterin-ether and benzoic isocholesterin ether, a third compound in quantity sufficient for examination. A third kind of ether, however, might escape observation if soluble in spirit of wine, even though present in larger quantity. We have, therefore, when continuing our researches, converted a part of the wool-grease alcohols (from the sparingly soluble portion of b) into benzoic ethers by prolonged fusion with anhydrous benzoic acid. In this case it may be safely inferred that none of the alcohols remain uncombined. The resulting mass was freed by proper treatment from the excess of anhydrous benzoic acid and from the hydrous benzoic acid which had been formed. The residue then contained all the wool-grease alcohols in combination with benzoic acid. Of this residue, about 20 per cent was soluble in hot spirit of wine. The solution deposited oily drops which, even when perfectly cold, remained soft and amorphous. They consisted of a benzoic ether, differing widely in its properties from the benzoic ethers of cholesterin and isocholesterin. From these two compounds it can be separated with tolerable completeness by extraction with cold aceton. On decomposition with alcoholic potash, this compound yielded, along with benzoate of potash, an alcohol which readily dissolved in ether, aceton, and spirit of wine, but did not crystallise from any of these solvents. It melts at a gentle heat, and cannot be distilled without decomposition. A substance of quite similar properties was also obtained from the portion of wool-grease readily soluble in alcohol. It contained 80 14 per cent of carbon, and 12:29 per cent of hydrogen. Three alcohols can, therefore, be isolated from woolgrease-cholesterin, isocholesterin, and an amorphous alcohol. The properties of the last-mentioned body afford no certainty that it is a definite chemical compound. It may consist of a mixture of several alkaloid bodies. Among the acids separated from the wool-grease, oleic acid seemed present in considerable quantity, but it was not obtained in a state of purity. The quantity of the fatty acids was not sufficient for complete decomposition by the method of fractionated precipitation; however, the presence was proved of a fatty acid with a very high equivalent, perhaps identical with the hyaenic acid of Carius. One hundred parts of the above-named portion of the wool-grease, b, yielded 53.1 parts of wool-grease alcohols. This number is in favour of the supposition that the sparingly soluble portion of this wool-grease only consists of compound ethers. For 100 parts of a mixture (in equivalent proportions) of oleic cholesterin ether, stearic cholesterin ether, and the corresponding isocholesterin compounds, would yield, on decomposition, 58.8 parts of cholesterin+isocholesterin. 100 parts of the analogous oleic and hyaenic compounds would produce 52.5 parts of cholesterin+isocholesterin. The presence of the amorphous alcohol in the mixture would not make much difference in the quantity of alcohol obtained on decomposition, since, judging from the composition of its benzoic ether, it combines with as much acid as does cholesterin. With the sparingly soluble portion of the grease c the case was different. 100 parts yielded 47'1 parts of woolgrease alcohols. This quantity is not sufficient to saturate the acids present. A portion of the latter must, therefore, be present in a free condition, and, in fact, that alcoholic extract of this grease has a strongly acid reaction. As was formerly mentioned, on the decomposition of the sparingly soluble portion of the wool-grease earlier examined alcohols and acids were found in such proportions that the presence of free fatty acids was suspected. But this assumption could only be regarded as doubtful, since the question still remained why these free acids were not removed by treatment with spirit of wine. ow be explained, se there occur oluble. since it has been shown fatty ac quis The bulk of wool-grease, therefore, consists of compound ethers, but a part of the alcohols (cholesterin, at least), and occasionally of the fatty acids, are in a free condition. PROCEEDINGS OF SOCIETIES. MANCHESTER LITERARY AND PHILOSOPHICAL SOCIETY. Ordinary Meeting, December 15, 1874, EDWARD SCHUNCK, PH.D., F.R.S., &c., President, in the Chair. MR. JOSEPH CARRICK and Professor Morrison Watson, M.D., were elected Ordinary Members of the Society. Analysis of one of the Trefriw Mineral Waters," by THOMAS CARNELLEY, B.Sc. Communicated by Professor H. E. ROSCOE, F.R.S., &c. An analysis of this strongly ferruginous mineral water has not, so far as the author has been able to learn, been published before any scientific Society; and though two general analyses of it have previously been made, the first by Mr. D. Waldie, in 1844, and the second by Dr. Hassall in 1871, and published in the form of pamphlets for public reading by Dr. Roberts and Dr. Hayward respectively, yet as it is peculiar for the extremely large quantity of iron and alumina that it contains, and as its composition has varied considerably since it was analysed by the last named chemist (whose results also varied from those of the first), it is thought that another and more complete analysis will not be out of place. The village of Trefriw is situated on the left bank of the Conway about 2 miles from Llanrwst and between. the latter place and Conway. The springs, which now belong to a company and are often visited by invalids, as they are said to be good for the cure of diseases of the digestive organs and of the skin, are close to the high road which runs between Conway and Llanrwst, and are rather over a mile from the village. The entrance to them is a short way up the side of the mountain called the Alt cae Coch, and consists of an underground passage cut in the rock. There are at present two springs (formerly there were three), one opposite and close to the entrance, the other at the end of a gallery 10 or 12 yards long to the right. The former water is used to supply the baths, and the latter exclusively for drinking; they differ considerably in the relative proportions of their mineral constituents, but it is only the last named which is the subject of this paper. The water, which flows into a basin cut in the rock, is said to be uniform in quantity and issues at the rate of about 40 gallons per hour; its temperature varies only within very narrow limits and is quite cold. As it occurs in the spring it is perfectly clear, bright, and colourless; but after a short exposure to the air it turns yellow and deposits flakes of ferric oxide; it has no smell, but possesses a strong and very disagreeable inky taste. being shaken up in a closed bottle no disengagement of gas takes place; it has a strongly acid reaction, and contains neither free carbonic acid, carbonates, nor sulphides; and when first taken from the spring is perfectly free from ferric salts. On The following (I.) is the analysis made of the water collected by the author on September 8th, 1874, together with that (II.) made by Dr. Hassall in the early part of September, 1871,* or just three years previously. Temperature of the external air .. air at the spring 15'5° C. 12.5° C: 11'0° C. 28 Analysis of Trefriw Mineral Water. I. 100716 Specific gravity at 17° C. Loss on ignition Precipitate formed on boiling one hour Iron .. Aluminium Calcium Magnesium Potassium Sodium Manganese Lead II. 100570 Parts per 1,000,000. 233°3 271'3 116'5 134'1 45'4 31'5 25'1 The residue dried at 310° C.. 7370'00 CHEMICAL NEWS, being too large for the total acids, the sum of the oxides (Fe2O3+Al2O3+P205) calculated from the Fe, Al, and P2O5, each estimated directly, is rather greater than the result obtained by weighing the three oxides together, the numbers being 2592 and 2570 respectively-difference 22. (3). In the determination of the alumina it was separated from the iron by means of tartaric acid and sulphide of ammonium, and weighed as Al2O3+ P205; the difference between this and the determined amount of P2O5 gave the quantity of alumina. (4). The phosphoric acid was estimated by precipitating with ammonium molybdate, and as the amount was only small, by weighing the precipitate obtained on a constant filter; the calculation was then made from the composition of the precipitate, which contains, according to various authorities, 3142 per cent. P2O5. (5). The iron was determined directly at the spring with potassium permanganate, and afterwards gravimetrically in the laboratory. The results obtained agreed very nearly. (6). Several determinations were made of the alkalies, but rather varying results, comparatively, could only be obtained for the sodium. The above is the mean of four, of which the highest was 32 and the lowest 22 parts per 1,000,000, the reason being that the quantity of sodium The following table represents the above in combina- present was only very small, so that the traces of it also contained in the reagents had an appreciable effect, though they were as pure as could be obtained. The results got for the potassium, however, agreed very nearly. (7). The lead was determined by the method given in Wanklyn and Chapman's "Water Analysis," as were also the ammonium, albumenoid ammonia, and nitric acid. By a comparison of the above two analyses it is evident that between September, 1871, and September, 1874, the composition of the water has varied considerably, and though the author has not had an opportunity of seeing the analysis made in 1844 by Waldie, yet from Dr. Hassall's report, given in the above-mentioned pamphlet, it would seem that the results there given also vary much from those obtained by Waldie. The quantity of iron appears to have greatly diminished, while, with the exception of SiO2 and chlorine, that of the other constituents occuring in larger quantities has considerably increased. A determination of the iron made last February gave 14 Loss 1575'4 parts per 1,000,000, though in this case the determination was not made till after the water had been collected some days. From this it would seem that the iron The result, however, obtained by Waldie is very nearly the same as that got by Hassall. 6970'9 With reference to this analysis the following observa tions are to be made : is gradually diminishing in quantity. (1). The determination of the total residue was first made at 180° C., as recommended by Fresenius, and the is peculiar, as already mentioned, on account of the large From the analysis it will be seen that the Trefriw water result obtained corresponded to 8100 parts per 1,000,000; quantity of sulphate of iron which it holds in solution; it was found however that this was much too high, the there being, so far as the author has been able to learn, reason being that ferrous sulphate, though it loses six no spring in the United Kingdom, and perhaps not even molecules of water at 114° C., yet retains the seventh even at 280°+. In order to drive off this remaining mole-ing to the same amount, while there are only a few springs on the Continent, which contains it in anything approachair bath to 300°-310° and weighed; after repeated heat-known which contain it even in a notable quantity, the ing two successive weighings did not differ by more than a milligramme. In heating to so high a temperature, however, there is a danger of a little sulphuric acid volatilising by decomposition of the sulphate of iron, but by careful heating this may be avoided; a loss of ammonia will, nevertheless, have been incurred, but as this, together cule, the residue from 100 c.c. of water was heated in an with the trace of organic matter, did not amount to more than 8 to 10 parts per 1,000,000, it was not of very much consequence. (2). It will be seen from the table showing the supposed combination of the salts, that the total bases formed were ather more than sufficient to combine with the acids, and he base which is given above as uncombined is alumina, as it is thought that the quantity of this body obtained was rather too high, for, in addition to the total bases *Fresenius, "Quantitative Analysis." 4th Edition, p. 560. + Watts, "Dictionary of Chemistry," vol. v., p. 597. analyses of which have been described. The water is alumina and silicic acid which are dissolved in it, while also remarkable for the large quantity of sulphate of the phosphoric and nitric acids, though existing only in small amounts, are rather large compared with what is found in most other mineral waters; on the other hand, the proportion of chlorine is only small. from Dr. Hassall's analysis of the two waters, it appears The other Trefriw mineral spring was not analysed, but alkalies and alkaline earths than the one which is the subto contain less iron and alumina, but a larger quantity of ject of this memoir. the source of the mineral impregnation of the springs, it With regard to the geological position of Trefriw, and may be observed that the mountains at the base of which the wells are situated consist chiefly of beds of limestone, ironstone, alum slate, and iron pyrites, together with vary. ing proportions of silicates, very much fractured and dis located, forming the northern extremity of the Bala or Caradoc beds. Up in the mountains and on these beds lie some small lakes from which the springs are supposed to derive their principal supply of water, which, after percolating through the above beds and dissolving large quantities of their constituents, finds its exit near the base of the mountain Alt cae Coch, where it issues from the slate bed (Black Band), and between it and the ironstone. From the above data the composition of the water is easily accounted for. There are several pyrites mines in the vicinity, one of which is situated just over the springs, but much further up the mountain side. The author has been indebted for Dr. Hassall's analysis and some of his remarks relative to the geological position of the springs to the pamphlet of Dr. Hayward previously mentioned. NOTICES OF BOOKS. THE TESTING OF ARTIFICIAL COLOURS. Die Chemische Prufung der kunstlichen organischen Farbstoffe. Von Dr. FERD. SPRINGMÜHL. Leipzig: Weigel. DR. SPRINGMÜHL, the editor of the Musterzeitung lays before the scientific and technological public, in this pamphlet, an account of the incidental impurities and intentional sophistications occurring in artificial colouring matters, and directions for their detection. Natural organic dyes are to be considered in a future treatise. We may mention as a somewhat disappointing circumstance, that while the introduction leads us to expect some mention of the colouring matters of uric acid and of the alkaloids, they are omitted in the body of the work. As regards picric acid the author finds that oxalic acid is not merely present in many samples as an incidental byproduct, but is sometimes intentionally added to the extent of 20 per cent. Samples of phenyl-brown are sometimes largely adulterated with sawdust and fragments of lignite (brown-coal). Oxalic acid and dinitrophenol are also present. The poisonous properties ascribed to corallin, and to goods dyed with this colour naturally called for the author's attention. He pronounces pure corallin not more poisonous than the remaining phenyl-colours, but finds that it may contain aniline, iodine, mercuric chloride and especially carbolic acid, to which latter he ascribes a great part of the toxic phenomena observed in the case of this dye. For the detection of carbolic acid in corallin he recommends Landolt's test. The sample is dissolved in water, held up to the light and mixed with bromine water. If carbolic acid is present a precipitate or turbidity of tribromphenol appears. Aniline, however, if present, is thrown down at the same time. In his general remarks on the aniline colours the author informs us that:-French qualities are the most frequently adulterated, whether by the manufacturers themselves or by middlemen. English samples, as far as I have had the opportunity of observing, are distinguished by great purity and excellence." Out of 25 specimens of magenta one only was found free from arsenic. In 14 the amount was sufficient for quantitative determination. In four samples the proportions were respectively 6'5, 5'9, 5'9, and 5'1 per cent. Such qualities, of course, must prove dangerous if used for colouring liqueurs, confectionery, and toys. In dyeing, however, the amount of the poisonous matter which attaches itself to the wool is relatively trifling. This the author ascertained by an interesting experiment. In a beaker he dissolved o'i gramme of the most poisonous sample in hot water. The solution, of course, contained 0.0065 gramme of arsenic. In it a square foot of pure wool (woollen tissue) was dyed. It was then well rinsed in a second beaker of pure water, and again in a third. The dyed wool, the residual dye, and the two wash-waters therefore contained o'0065 of arsenic, and it remained to ascertain its distribution. In the dye-bath were found 0.0051 gramme, in the first washing-water o'ooro. In the second washing-water the amount was too small to be determined. It, however, and the dyed wool must together contain the residue o'0005. According to Marsh's test the wool appeared to contain less than the second washing water. Hence a square inch of the woollen could contain scarcely two millionths of a gramme of arsenic. If the proportion of arsenic is low, as in wellpurified magentas, the wool, when dyed gives no indications by Marsh's process. It is of some importance to know of what salt of rosanilin a commercial magenta consists, as the proportion of base varies, the muriate being richer than the acetate. The mercurial process for the manufacture of magenta is still used in some establishments. The author found the crystals of such samples smaller than those of arsenical magentas. Two of the specimens examined contained arsenic, which renders their origin doubtful. In none was mercury detected. The two most frequent adulterants are oxalic acid and sugar. The author has found 21 per cent of the former, and 24 per cent of the latter. Joly has detected sugar to the extent of 50 per cent. Aniline violets are more liable to sophistication than magentas from the fact that they are sold, not in welldefined crystals, but in powder or in cakes. The author has detected gum in a Hofmann's violet to the amount of 12 per cent, and 8 per cent of finely ground charcoal in a common phenyl violet. Aniline blues are treated very briefly. The author does not specify any adulterations as having actually occurred in his investigations, but he recommends consumers to have an eye to the possible presence of sugar. Of 32 samples of iodine-green examined, 5 were unquestionably sophisticated. One contained 18 per cent of sugar. An English sample was cleverly sophisticated with a salt of lead, probably the picrate, and deflagrated when a portion was heated upon platinum foil. Metallic lead was found to the extent of 10 per cent, corresponding to 21 per cent of the picrate. Two other samples contained respectively 14 per cent. of common salt and 26 per cent of magnesia. Oxide of chrome is also a possible adulteration. The finest sample of iodine-green examined was from the manufactory of H. Siegle, in Stuttgart. The author considers that in the production of this beautiful and costly colour the Germans are superior to the English and the French. We shall probably again return to this book on some future occasion. Meantime we feel bound to call to it the especial attention of such of our readers as are connected. with dyeing, calico printing, or the manufacture of colours. |