with the tetrad carbon. We thus see how in so many of THE CHEMICAL NEWS. it compounds cyanogen acts as a monad exactly in analogous to chlorine. IN a suggestive paper publish the CHEMICAL NEWS Power of the molecule. (vol. xxxiii., p. 141) Mr. attention to the But further, just as we find nitrogen combining with itself in the oxides of nitrogen and in the azo-phenyl compounds; and as we find carbon combining with itself to form the connecting link of an organic body, so we may consider that cyanogen combines with itself to give us the more complicated cyanides; and as the addition of each atom of carbon makes an addition of two to the saturation-power of a molecule, so the addition of each group CN causes the addition of one to the saturationIt is of course possible that the addition of the cyanogen saturated atomicities of nitrogen, and this may account for certain instances of isomerism, e.g., paracyanogen ; but this point we have at present no means of deciding. strictly belonging to the cyanogen group, we may arrange Leaving out of consideration the iso cyanides as not the cyanogen compounds into different classes as they contain once, twice, three times, &c., the group CN'=Cy'; thus we have : cyanogen, and draws the conclusion that lationships of groups takes place by the combination of the two self nearly similar in its properties to oxygen than it is to chlorine. It may be of value to attempt to classify a few of the more important cyanides and then to examine the arguments brought forward by Mr. Skey. From the intimate connection between the various members of the cyanogen group, they are, in general, considered together as a separate section of organic chemistry. In a general review of these bodies the first thing which strikes us is the large number of compounds in which CN plays the part of a simple monatomic element; the second is the numerous complicated compounds containing the group CN more than once. Considering, then, the cyanogen compounds as a group to themselves, it is evidently of advantage to use as our means of classification the groups CN, and not, as is usually the case, the various bodies with which it may happen to be combined; just as the paraffins, for example, are classified by the number of atoms of carbon which they contain. Our next step is to enquire into the constitution and combining powers of the group CN on which our classification is to be based. Carbon is in almost all its compounds a tetrad, e.g., CH4, CCl4, &c.; it is, however, sometimes a dyad CO. Again, carbon may saturate some of its affinities by combining with itself C2H5C1,C2H4, &c. Nitrogen in many of its combinations plays the part of a pentad NH4C1, NH2(CH3)'HBr, &c., in others it acts as a triad NH3N(CH3)3, &c.; in one of its combinations, NO, it is apparently a dyad, and in another, NOH, a monad. Like carbon it possesses considerable power of self-saturation. From the more general valencies of carbon and nitrogen we should expect cyanogen to be tetradic carbon combined with either pentadic or triadic nitrogen. There was considerable doubt as to which of these formulæ belonged to cyanogen until Dr. Hofmann's brilliant discovery of the iso-cyanides, bodies clearly belonging to the former class. They are formed by distilling a mixture of an alcoholic ammonia base and chloroform with alcoholic potash C6H2N+CHCl3=3HC1+C6H5.N.C. The iso-cyanides are scarcely acted on by alkalies, but break up under the action of acids into formic acid and an alcoholic ammonia C6H5NC+2H2O=C6H5NH2+H2CO2. (Cy1)'(Cy2)'' (Cy3)'''(Cy4)'''', &c. By this of course we entirely throw over the system of types, and classify by valencies which are in reality at the root of that system. What is the so-called water type but two monad groups each united to one dyad group, and so on for the other types? It must be admitted that in where perhaps there ought to be none, e.g., between several cases this method of classification places divisions melamine and melam, and between potassium cyanide and zinc cyanide; but I venture to hope that it is at least no worse in this respect than any other system of classification which has been proposed. Many of the cyanogen compounds are so difficult to examine that the difficulty of the classification consists as yet in their true empirical formula, and this can only be overcome by a very extended series of accurate analyses, e.g., the nitroprussides. We know of cyanogen compounds which contain the group CN from 1 to 18 times, but many of the intermediate groups are still wanting. It may be of interest to arrange the more important of the cyanides of organic bodies, as they are, in general, cyanides under their respective classes, putting in but few simple and would cause useless repetition. Monocyanides (Cy1)'. CyH, prusssic acid CyCH3, methyl cyanide CyAg, silver cyanide Cy K, potassium cyanide CyNH4, ammonium cyanide Under similar conditions ordinary phenyl-cyanide breaks sulphocyanates. up into prussic acid and phenyl-chloride CNC6H5+HCl=C6H5+CNH. Further confirmation of this view that cyanogen consists of tetradic carbon and triadic nitrogen is afforded by M. Gaultier's and Gal's discovery of the hydro-chlorates, hydro-bromates, and hydriodates of the cyanides and cyanates. In these bodies evidently the two atomicities of nitrogen previously saturated by one another are now saturated by hydrogen and chlorine, &c., just as we have ammonia and its congeners forming the ammonium salts. In the great majority of the cyanogen compounds we may leave out of consideration the fact that nitrogen is a pentad, and regard it simply as a triad in combination CyNH2, cyanamide ate CyOC2H5, ethyl cyanate CySNH4, ammonium sul- CyBr, cyanogen bromide Dicyanides (Cy2)". Cy2(OH)2, dicyanic acid Cy2S, cyanogen sulphide Cy2(NH2)2,dicyano-diamide Cy2(NH2)OH, dicyanamic acid Cy2H2(SH)2 (?), cyanogen We are here met by one of the first difficulties of our classification. Should such a body as Cy2Cu be placed here or in the first class, that is to say are the cyanogen groups directly connected together, or is each only connected with copper? It appears to me, looking at the ease with which the cyanogen groups coalesce, that the first case is probably the true one; but the point needs further investigation. Recent determinations of the vapour density of liquid cyanogen chloride seem to point to the formula CyCl, but it is possibly a case of dissociation. The dicyanic acid mentioned is of course not fulminic acid, but the true dicyanic acid discovered by Poensgen. Cyanogen disulphydrate and persulphocyanic acid are very difficult bodies to classify. It seems possible that the two latent nitrogen affinities of the cyanogen may here come into play. Cу6Fe23H2O, ferric cyanide acid Ferric cyanide is obtained according to Wyrouboff when potassium ferrocyanide is boiled with ammonium chloride. Hepta-cyanides (Cy)vII. Octo-cyanides (Cys) vIII. CysFe2Fe.4H2O, magnetic cyanide of iron of Pelouze Ennea-cyanides (Cy9)1x. Cy9H6(OH)3, azulmic acid of Gautier Deka-cyanides (Cy10). CyroPt2K4, potassium platino-cyanide Cy12 Fe2H6, hydrogen ferricyanide Cyr2FezNi(NH3ni) 2, nickelic nickelammonium ferricyanide Cy12Fe2K3Na3, potassium and sodium ferricyanide Cy12Fe2Fe3, ferrous ferricyanide Cy12Fe4, ferric ferricyanide (Prussian green) Cу12C02K6, potassium cobalto-cyanide Cy12Mn2K6, potassium manganic cyanide CyraCraK6, potassium chromicyanide Do-deka-cyanides (Cy12)x, (See preceding page). Octo-deka-cyanides (Cy18)XVIII. Cy18(Fe3)IFe (?), Prussian blue. " Besides theoretical reasons, based upon the atomicity of iron, for considering the ferro- and ferri-cyanides as containing the group CN twelve times in each molecule; the single molecule of water found by Wyrouboff in calcium ferrocyanide dried at 100°, and the three molecules of water found by the same observer in potassio-strontium ferrocyanide dried at 110°, the constitution of Laurent's potassium and sodium ferricyanide, and finally the constitution of the ammonio-silver ferricyanide furnish powerful arguments tending in the same direction. Nickel seems to form nickelo-cyanides similar to the ferrocyanides; cobalt, manganese, and chromium form cobalti-cyanides, mangani-cyanides, and chromi-cyanides similar to the ferri-cyanides. The formula of Prussian blue has long been a vexata quæstio among chemists; that given above is the older and perhaps more generally received. (To be continued) REPORT ON THE DEVELOPMENT OF THE CHEMICAL ARTS Progress in the Artificial Production of Cold and Ice. A FEW singular proposals for effecting a reduction of temperature may be finally mentioned. J. B. Toselli, of Paris,t causes a spiral pipe to revolve in a vessel of water, from which it simultaneously, during each rotation, raises a certain quantity of water and transfers it to an adjacent vessel, whence it flows back through a worm into the former. The spiral, during its revolutions, has its entire surface moistened. A ventilator drives air against it, evaporates the adhering layer of moisture, and thus lowers the temperature of the tube and of the water it contains. A refrigeration of from 2'7° to 18.3° C. is said to be thus produced according to the weather. In the second vessel, which is traversed by a worm containing the cold water, is placed the liquid to be cooled, such as worts of beer, artificial mineral waters, &c. The effect produced can be but trifling, and depends entirely on the state of the weather, and on the amount of atmospheric moisture, which is never wanting. A psychrometer fixed in the place where the experiment is to be made will show the result beforehand with tolerable accuracy. Ballo, of Pest, produces cold by forcing very finely divided air through bisulphide of carbon. The condensation of the liquid needful for its recovery is a hindrance, on which, in fact, the entire project must be wrecked. A recovery of the bisulphide of carbon by any other means than by condensation and refrigeration of the air saturated therewith is, in the absence of suitable solvents, "Berichte über die Entwickelung der Chemischen Industrie Während des Letzten Jahrzenends." + Toselli, Mech. Mag., 1872, 433. Dingl. Pol. Journ., ccv., 28. Ballo, Dingl. Pel. Journ., ccxi., 345. impossible. Even by this means it would involve much difficulty and a great expenditure of force, and would bring us back to the principle of the air machine. In this direction the problem is practically incapable of solution. Preservation of Ice. As a supplement to our report on the principles of the artificial production of ice, and on the apparatus hitherto devised for this purpose, a few words must be added on the arrangements for the preservation of cold in the concentrated form of ice. This is a question of great practical importance. Ice machines, however they may be eventually improved and their effect increased, will never, in the more northern parts of the temperate zone, where a moderately cold winter with frost is generally experienced, acquire importance enough to meet the demand even approximately. They will serve merely as valuable substitutes to render us independent of the fickleness of the seasons. Even in more southern regions where ice machines are the only source for obtaining ice, they must work to stock and fill magazines, since the demand does not go hand in hand with the production, but varies with the weather. There is in general no conception of the quantities of ice which certain trades require, and which are consumed in domestic life where its use has grown into a necessity. In 1866 the quantity of ice consumed in New York and its vicinity amounted to 250,000 tons (254,015 metric tons) or 5 cwts. per head. The weight stored up was 543,000 tons (551,721 metric tons), whilst the capital employed in the trade amounted to 2,160,000 dollars. The retail price was for quantities of 5 to 12 kilos. 4 pfennige* per kilo., but for quantities of I to 10 cwts. only one shilling per cwt. In 1871 a company in Berlin, the "North German Ice Works," stored up 600,000 cwts. of ice, and delivered it to subscribers at 77 pfennige per cwt. The quantities of ice consumed in brewing may be learned from the following data, which the author obtained in 1869 from Dreher's brewery at Klein Schwechat, near Vienna :-This establishment brewed, in 1867, 483,150 Viennese eimers, = 273,463 hectolitres, and stored up 515,600 cwts. (28,874,219 kilos) of ice. In the following year these numbers rose to 492,499 eimers (278,754 hectolitres) of beer and 563,058 cwts. (31,531,924 kilos.) of ice. On an average I cwt. of ice is used per eimer (56.6 litre). In a prolonged frost of 2 months this quantity can be procured at the cost of 7 Austrian kreutzers (14 pfennige) per cwt. In shorter periods of cold the price rises to from 10 to 12 kreutzers, to which must be added I kreutzer for shovelling into the ice cellars. In mild winters the ice is brought in part from Styria; as the cold weather in 1869 set in late, 26,000 cwts. (1,456,031 kilos.) were procured from there, costing, by the time it reached the brewery, 115 florins per 200 cwts. (To be continued.) SCHEIBLER'S PROCESS FOR SACCHAROSE ESTIMATION. By ROBERT FRAZER SMITH. WITH reference to the very able abstract of Professor for the determination of the crystallisable cane sugar in Gunning's remarks in his report upon Scheibler's process Chemist and copied in the CHEMICAL NEWS (vol. xxxiii., raw sugars given by Mr. Humphrey in the American p. 205), perhaps the enclosed table of results obtained by the use of that process upon Colonial sugars by Lotmann time or opportunity afforded for giving it a fair trial. may be of interest to those chemists who have not had Owing to the results being uniformly higher than those *The German "pfennig" is about the tenth part of an English penny. Table of the Refining Values (Raffinations Werthes) of Different Raw Sugars. 100 Parts of the Raw Sugar Contain 95'0 86.60 89.87 99'2 87'0 1.680 3rd product found by the French method, it probably has no chance of being adopted by the buyers of raw sugars or those acting for them; but in the private laboratories of refineries the information such a determination of the actual quantity of saccharose present in any sample gives may induce some chemists to procure or erect the apparatus. The Table will show that it is absolutely indispensable to dry all samples containing more than 2 per cent of moisture previous to treatment, in which case the ether will be unnecessary. Upon sugars containing much caramel or other colouring matter an alcoholic 3 per cent hydrochloric acid solution will be found to answer better than the acetic, giving at the end a perfectly white product. With regard to the "amorphous sugar" it might be well to wait for more light before accepting the existence of such a body. The sugar obtained by precipitating with alcohol from a sample of molasses which has stood for a year without any signs of crystallisation, presents the appearance of an impalpable powder, and from its state of minute division is slightly more soluble in alcohol than the crystalline cane sugar of commerce, containing 99.8 per cent of saccharose, but on solution in water and evaporation it crystallises in the ordinary form. Crystalline salts dissolved in gum or gelatin behave in exactly the same manner, but no one has yet talked of amorphous common salt or nitre. Molasses containing, on dried product | But exposed to a freezing mixture to get rid of excess of salts and saccharose, the mother liquor, treated with alcoholic ether (being first concentrated) yields a large crop of what I understand to be the so-called amorphous sugar. a glass of small power shows distinct crystalline faces, and it yields to water and evaporation, the usual result. I humbly think that the amount of crystallised sugar got from any solution of saccharine matter will be found to depend, other things being equal, upon the value which pertains to the figure denoting the coefficient of viscosity. Some salts, such as the magnesian, instead of hindering promote sugar crystallisation. In short, the salts which take longest when in solution to transpire through capillary tubes are those which hinder crystallisation most. Hence the alkaline organic salts are the great molasses formers, and hence also the benefit derived from Marguerite's process in the beet fabriques, which adds sufficient hydrochloric acid to transform these into chlorides, the other acids being sent off in the boiling. The rate at which any syrup travels through a capillary tube (a solution of pure sugar being 100) will express the crystallising capabilities of the sugar contained in it; due regard being had to temperature, pressure, strength, &c., being alike in the various trials. Mr. Humphrey mentions cases in which glucose is present in an optically inactive condition, but, so far as I know, this never occurs in cane sugars, but is so abundantly in date sugar and also the sugar from many fruits. 23, Roselea Drive, Glasgow. The Loan Collection at South Kensington.-A series of lectures in connection with the above Exhibition have been arranged for the free evenings. The first lecture will be given on Saturday evening next, at 8 o'clock, in the Conference Room, by Prof. Roscoe. The subject is "Dalton's Instruments and what he did with them," NEWS UNIVERSITY COLLEGE, BRISTOL. THE operations of this new College will, we are glad to hear, begin in October next in the temporary premises, Park Row, Bristol. It will be remembered that the College is established for the study of science and literature for young people of both sexes above the ordinary school age residing in the West of England and South Wales. The models kept in view are University College, London, and the Owens College, Manchester. The Council consists of Prof. B. Jowett, nominated by the Vice-Chancellor of the University of Oxford; Prof. Stuart, nominated by the Vice-Chancellor of the University of Cambridge; Mr. W. Lant Carpenter, nominated by the Chancellor of the University of London; Prof. H. Smith, by Balliol College, Oxford; Rev. H. B. George, by New College, Oxford; Mr. R. W. Coe, by the Bristol Medical School; Mr. F. N. Budd (Chairman); Mr. W. Proctor Baker (Treasurer); Rev. J. W. Caldicott; Mr. Lewis Fry; Rev. F. W. Gotch; Rev. J. Percival; Mr. G. F. Schacht; and Mr. William Smith, the last eight gentlemen being elected by the subscribers. Out of 106 candidates Mr. Edward Stock, of Clare Street, Bristol, has been elected Secretary. The Council will shortly appoint a Professor of Chemistry. The necessary qualifications are, first, a good teacher; and, second, one who has done and will do original work. The Council offer £300 per year, two-thirds of the Lecture Fees, and one-third of the Laboratory Fees, the College finding the Laboratory in apparatus and chemicals, and they guarantee a minimum emolument of £400. In order to improve the technical education of those engaged in the cloth-making districts in the West of England, the Clothworkers' Company offered to the promoters of the College the subvention of 500 guineas per year for five years to assist in the establishment of a Department of Textile Industries at the College, and it is understood that special attention will be given both to the principles and detail of the mechanism employed in cloth manufacture, and also to the chemical principles involved in the processes of wool-scouring, dyeing, &c. In addition to the instruction given at the College there will probably be classes conducted in the cloth-working districts themselves, at Stroud and elsewhere. Mr. W. ACKROYD read a paper on "Selective Absorption." Two typical experiments were shown upon which a division of selective absorption may be based. In the first, light is transmitted through bichromate of potash at the normal temperature, and again at about 200° C., and the spectrum of the transmitted light is examined. The widening of the absorption-bands, which takes place at the higher temperature, is traced .o structural alterations. In the second experiment, light is sent through two thicknesses of the same coloured solution-as, for example, sulphate of copper-and in the greater thickness the absorption-band has widened out; but this is plainly not owing to any structural alteration. That in the first experiment he proposes to term structural, and that in the second transverse absorption, and he considers that these two kinds have not hitherto been sufficiently distinguished. Certain colour relations which exist among anhydrous binary compounds led the author to the conclusion that the width of a structural absorption-band bears a direct relation to interatomic distance. The necessity for separating high temperature spectra from low was shown, and the bearing of the subject on the study of organic colouring matters briefly alluded to. The SECRETARY then read a communication from the Rev. R. Abbay, "On certain Remarkable Atmospheric Phenomena in Ceylon." The most striking of these is witnessed from the summit of Adam's Peak, which is a mountain rising extremely abruptly from the low country to an elevation of 7200 feet above the sea. The phenomenon referred to is seen at sunrise, and consists apparently of an elongated shadow of the mountain, projecting westward to a distance of about 70 miles. As the sun rises higher it rapidly approaches the mountain, and appears at the same time to rise before the observer in the form of a gigantic pyramid of shadow. Distant objects may be seen through it, so that it is not really a shadow on the land, but a veil of darkness between the peak and the low country. It continues to rapidly approach and rise until it seems to fall back upon the observer, like a ladder which has been reared beyond the vertical, and the next instant it is gone. Mr. Abbay suggest the following explanation of the phenomenon :-The average temperature at night in the low country during the dry season is between 70° and 80° F., and that at the summit of the peak is 30° or 40° F.; consequently, the low strata of air are much the less dense, and an almost horizontal ray of light passing over the summit must be refracted upwards and suffer total internal reflection, as in an ordinary mirage. On this supposition the veil must become more and more vertical as the rays fall less horizontally, and this will continue until they reach the critical angle, when total internal reflection ceases, and it suddenly disappears. Its apparent tilting over on the spectator is probably an illusion, produced by the rapid approach and the rising of the dark veil without any gradual disappearance which can be watched and estimated. It will be evident that the illumination of the innumerable particles floating in the atmosphere causes the aërial shadow to be visible by contrast. Another interesting phenomenon visible in the mountain districts admits of an equally simple explanation. times broad beams, apparently of bluish light, may be seen extending from the zenith downwards, converging as they approach the horizon. The spaces between them have the ordinary illumination of the rest of the sky. If we suppose, as is frequently the case, that the lower strata of air are colder than the upper, the reflection spoken of in the case of Adam's Peak will be downwards instead of upwards. If several isolated masses of clouds partially obscure the sun, we may have several corresponding inverted veils of darkness, like blue rays in the sky, all apparently converging towards the same point below the horizon. This latter phenomenon is called by the natives "Buddha's Rays." At Prof. Dr. FOREL, of Morges, Switzerland, then gave, in French, an account of some interesting observations which he has recently made on the periodic waves which take place on the Swiss lakes, and are there called "Seiches." It was long since observed that the waters of most of these lakes are subject to a more or less regular rise and fall, which at times have been found to be as much as I or 2 metres. M. Forel has studied this phenomenon in nine different lakes, and finds that it varies with the length and depth of the lake, and that the waves are in every way analogous to those already studied by Prof. Guthrie in artificial troughs, and follow the laws which he has deduced from his experiments. Most of the observations in Switzerland were made on the Lake of Geneva, but that of Neuchatel was found to be best fitted for the study of the subject, possessing as it does an extremely regular geometric form. The apparatus he employed was very sensitive to the motion of the water, being capable of registering the waves caused by a steamboat half an hour after it had passed, and five minutes before its arrival, and was so constructed as to eliminate the effect of common |