94 Effect of Light on the Electrical Conductivity of Selenium. 66 Selenium." By O. U. VONWILLER, B.Sc. 'Effect of Light on the Electrical Conductivity of take up a steady temperature in about ten seconds. The | superphosphate be added to the bare patches, which will pattern of the thermometer must also be suited to the pur- convert the manganese into a form in which it is probably pose for which it is intended. Three types were shown, less toxic than at present. designed for mouth, rectal, and surface work. Experiments were performed proving that these thermometers fulfilled the necessary conditions. The recording instru ments for use with these thermometers were briefly described. Prof. Callendar then showed continuous records obtained from a patient with a normal temperature. The temperature is generally very steady if the thermometer does not shift or the patient get wholly or partly out of The effects of external changes of temperature were also shown, and simultaneous records taken on different parts of the body illustrated the fact that the temperature does not vary in the same way at all places. may eventually result in important additions to knowledge. bed. On the medical side there is a vast field for research which ROYAL SOCIETY OF NEW SOUTH WALES. General Monthly Meeting, November 3rd, 1909. H. D. WALSH, B.A.I., M. Inst. C.E., President, in the Chair. THE following papers were read :— It is shown that on the incidence of light the conductivity of the selenium nearest the surface is increased most, the magnitude of the effect decreasing as the depth below the surface increases. The effect, however, is not limited to an exceeding thin surface layer, but an appreciable change is produced in many cases at depths of several hundredths of a millimetre. The rate at which the effect of the light used; it being found that it is much greater falls off with the depth penetrated varies with the nature with green light than with red. The sensitiveness of the results obtained indicate a greater absorption of green light cells tested is much less for green than for red light. The than of red, as was found by A. W. P. Fund (Phys. Rev. Mag., 1909), and it is shown that the smaller effect produced by the green light is not necessarily inconsistent with the view that the effect produced in any layer increases with the amount of energy absorbed in it. NOTICES OF BOOKS. "Corrosion by Gravity Streams, with application of Ice History of Hindu Chemistry. By PRAPHULLA CHANDRA Flood Hypothesis." By E. C. ANDREWS, B.A. "Occurrence of Manganese in Soil and its Effect on Grass and other Crops." By F. B. GUTHRIE, F.I.C., F.C.S., and L. COHEN. Samples of soil were examined, which were taken from bare patches occurring on a bowling-green in Dubbo. The sample examined was typical of forty or fifty small patches which appeared in the green last spring, and this spring, on which the grass dies out. Two peculiar points were noticed about the occurrence of these patches. In the first place, they did not appear for the first three years. The green was laid five years ago, and received the usual treatment throughout, cut and rolled daily, well-watered during the summer, and top-dressed early in the spring. In the second place, the grass dies in the winter and recovers when the warm weather sets in. Careful analysis of this soil showed no difference to that of soil taken from the same green in parts where the grass showed satisfactory growth, with the exception that the bare patches were found to contain small quantities of manganese (0.254 per cent Mn2O3), whilst the good ground contained none, or in quantities too small to determine by the methods adopted. A considerable quantity of work has been done on the subject of the influence of manganese on soils, especially by the Experiment Stations in Japan, Italy, and Hawaii, and the general results indicate that in small quantities manganese has a distinctly favourable action on the growth of many crops. Some chemists state that manganese is necessary to the growth of crops, and that all soils contain it in minute quantities. In larger quantities it has been found to act as a plant-poison, and experiments are referred to showing the limits of this toxicity. In Hawaii there is a condition of things very similar to that described from Dubbo. There are patches of land in Hawaii on which pineapple plants do not develop, turning yellow in colour, and producing inferior fruit. These soils are usually black in colour (the normal soils being red), and Mr. Kelley, the Chemist to the Agricultural Station, finds that these black soils contain on the average 5.6 per cent manganese oxide as against o'37 per cent on the good soils. The same peculiarity is noticed there, that these soils give good results for the first year or so, and that the toxic power of the manganese appears gradually to develop. On soils containing an intermediate proportion of manganese, namely, about 1.36 per cent, the peculiarity noted at Dubbo is also noticed, namely, that the plants die in the winter and recover themselves with the advent of the warm weather. To remedy the evil, a tentative suggestion is made that RAY, D.Sc., Ph.D. Vol. II. Calcutta: The Bengal Chemical and Pharmaceutical Works, Ltd. London: Williams and Norgate. 1909. POSSIBLY in order to appreciate fully this history of Hindu Chemistry the reader would have to possess a knowledge of Sanskrit, but even the uninitiated will readily see that the work possesses unusual interest. It contains many notes on Sanskrit texts, which showed that the knowledge of science possessed by the ancient Hindus was diversified and comparatively far-reaching, and many of the original texts are reproduced. The period treated extends from about 150 A.D. to 1600. Principal Scal, of the Victoria College, Kuch Behar, has contributed to the book articles on the Mechanical, Physical, and Chemical Theories of the Ancient Hindus, and on the Scientific Methods of the Hindus. Physical Chemistry for Electrical Engineers. By J. LIVINGSTON R. MORGAN, Ph.D. Second Edition. New York: John Wiley and Sons. London: Chapman and Hall, Ltd. 1909. THE first edition of this book was generally acknowledged to be a valuable introduction to physical chemistry, and the new edition, in which comparatively few alterations are to be found, will be welcomed by students and teachers alike. Beyond bringing the subject down to date and making a few alterations to simplify the text, the author has left the book unchanged; although he acknowledges the value of correct theoretical conceptions he believes, and believes rightly, that a practical working knowledge of a subject is best acquired by direct experiment, and by expressing all ideas as far as possible in terms of direct experiment. This certainly tends to produce clearer views, and greatly simplifies the study of physical chemistry for the practical purposes of the electrical engineer, for whom the book is primarily intended. The Recognition of Minerals. By C. G. Moor, M.A., F.I.C. London: The Mining Journal. UNTIL the appearance of this book the prospector had considerable difficulty in finding information which would lead to the identification of any mineral, and he will have reason to be grateful to the author for throwing light upon a troublesome operation. The book is intended for the use of observers in the field and more particularly for those who have not had the advantage of a thorough scientific training. No regular essays are described in it, but with NEWS SOURCES. NOTE.-All degrees of temperature are Centigrade unless otherwise expressed. its help the reader should be able to recognise by inspection | CHEMICAL NOTICES FROM FOREIGN and by the performance of quite simple tests all minerals which are of commercial value. The minerals are classified according to colour, which is certainly the simplest system, and only such tests are described as can be performed with simple apparatus and few reagents. In short articles the commercial value of the elements and the uses of their most important compounds are briefly summarised, to give the prospector some clue as to the price he may expect to get for a mineral, and also the degree of purity of the substance as it is put upon the market. The book contains in addition articles by D. A. MacAlister on Sedimentary, Igneous, and Metamorphic Rocks, and on the occurrence of mineral deposits. Kolloidchemische Beiheft. ("Colloidal Chemistry Supplement"). Edited by Dr. W. OSTWALD. Vol. I., Nos. I and 2. Dresden: Theodor Steinkopff. 1909. THIS supplement to the Kolloid-Zeitschrift is issued for the purpose of accelerating the publication of monographs which are too lengthy for insertion in the paper itself, but which it is desirable in the interests of science to make widely known as quickly as possible. The monographs are to deal with subjects connected with both pure and applied colloidal chemistry. Two long papers occupy the first issue. The first, by Dr. Johann von Schroeder, deals with the process of tanning, and in it conclusions of great | technical and scientific importance are reached; many experiments are described which were undertaken to elucidate the conditions of the adsorption of tannin, and a short discussion of the theory of the process is included. The second paper, by Dr. Hans Meyer, on an electric method of measuring the changes caused by light in chromate-gelatin layers, shows that the percentage change of conductivity is a magnitude which depends upon the light, and the article incidentally demonstrates the great value of the electric method of research in colloid chemistry. Die Elektromotorischen Kräfte der Polarisation. ("The Electromotive Forces of Polarisation"). By M. LE BLANC. Halle-a-S.: Wilhelm Knapp. 1910. THIS monograph opens with a description of the oscillograph, and gives a detailed account of the results obtained with it when the polarisations of various oxidation and reduction chains are measured, and also of polarisation measurements with metallic electrodes immersed in a salt solution. It was found that, in spite of sufficient ionic concentration, anodic and cathodic polarisation occur, the degree of polarisation being dependent on the temperature, the state of the electrodes, and other external factors. The author believes that the explanation of the phenomenon is to be found in the assumption that comparatively slow physical or chemical reactions occur. Matter, Spirit, and the Cosmos. By H. STANLEY REDGROVE, B.Sc. (Lond.), F.C.S. London: William Rider and Son, Ltd. 1910. THE thoughtful reader who is not satisfied with what materialism has to offer him will find food for reflection in this book, and even if he does not agree with all its conclusions he will gather from it a very fair idea of modern developments of the theory of the universe. It is very moderately written, and those who are seeking a rational interpretation of the cosmos, if they do not find it quite convincing, must credit the author with a genuine desire to aid in the solution of the problems of the existence of matter and energy. The influence of many schools of thought is clearly discernible in the author's writing; he has borrowed largely from Sir Oliver Lodge, and acknowledges his indebtedness to Swedenborg, and has obviously read widely. The problems put before the reader are such as are more and more occupying the minds of the leaders of scientific thought, and the author's conclusions are well stated and are based upon careful reasoning and accurate interpretation. Berichte der Deutschen Chemischen Gesellschaft. Earths of Euxenite.-Otto Hauser and F. Wirth.Yttrium earths, especially yttria, are present in comparatively large quantities in normal euxenites, and as the amount of titanium increases the ratio of holmium and dysprosium to neoerbium also increases. Terbium earths are present in small quantities, while euxenite is relatively rich in yttrium earths and scandium. Normal euxenites containing little tantalic acid but much titanic acid contain no samarium nor praseodymium. Thorium and uranium dioxides were comparatively abundant in the euxenites investigated. In typical euxenites zirconium earths are never present in large quantity, and the authors have not been able to detect the presence of any components corresponding to Hofmann and Prandtl's "euxen-earths." Double Haloid Salts of Tri-, Tetra-, and Pentavalent Antimony.-Fritz Ephraim and S. Weinberg.The thallium double chloride of tetravalent antimony readily gives a violet salt TISbC15, and the chlorination of a mixture of antimony trichloride and thallous chloride yields a compound of the same colour and having the formula TICI3.2TICI.2SbC14. These coloured compounds are very labile, the reaction SbC13+ SbC152SbC1, being dependent on the temperature and on the possibility of ionisation. When SbCl, and SbCl, are mixed without a solvent and warmed the mass beomes brown, but very little compound of tetravalent antimony is formed. If solid ammonium chloride is added the whole mass turns black, and from it a dark violet mass is obtained on cooling; this gradually loses its colour and becomes white, and the black form is evidently meta stable. Similar phenomena are observed with potassium chloride. The double bromide of tetravalent antimony (NH4)2SbBr6 can readily be isolated from solutions of SbBr3 and NH4Br in hydrobromic acid. Also 9NH4Cl.2FeCl3.3SbC14 has been prepared. The authors have not succeeded in isolating compounds of tetravalent antimony with alkylamine bases, nor double iodides of tetravalent antimony, but have obtained a series of hitherto unknown salts of tri- and pentavalent antimony, e.g., SbCl3. NH2. CH3. HCl. Double Fluorides of Monovalent Thallium.-Fritz Ephraim and Leonid Heymann.-For theoretical reasons it seems probable that double fluorides should exist in which the metallic ion has a low valency and a high atomic weight. Thallium answers to this description, and the authors have found that it yields double fluorides with manganese, such as 5TIF.2MnF3.MnF2; antimony, TIF.SbF3, TIF.2SbF3, TIF.3SbF3; vanadium,3 TIF.2VO2F, 2TIF.VOF2, TIF.VF3+2H2O, 2TIF.VF3+ H2O; tantalum, 2TIF.TaF5; tungsten, 2TIF.WO2F2, 3TIF.2WO2F2, TIF.WO2F2. Decomposition of Water by Hypophosphites in Presence of Palladium.-A. Bach.-If sodium hypophosphite and copper sulphate are mixed and the mixture is allowed to stand, copper hydride and phosphoric acid are formed, water being split up according to the equation PO2H3 + 2H2O = PO4H3+2H2. This is thus a case of the decomposition of water by an oxidisable substance in presence of another substance which combines with the hydrogen and prevents reduction taking place. Similar actions may very probably occur in the plant and animal organisms. The same reaction takes place when palladium is used as a catalyser, the action being dependent on the concentration of the catalyser and the hypophosphite. The palladium appears to form a compound with the hydrogen, possibly of formula Pd2H. When decomposed this may yield the hypothetical hydrogen suboxide or oxyperhydride OH4, and this in the catalysis perhydrides and oxyperhydrides correspond to the peroxides and hydroperoxides of biochemical oxidation processes. Red Phosphorus and Hittorf's Phosphorus.-Alfred Stock and Franz Gomolka.-Hittorf's red crystalline phosphorus can very readily be crystallised from a solution of phosphorus in bismuth or in lead. In order to get the crystals from a lead solution it is best to employ electrolysis, by which means about one-third of the phosphorus used is obtained in the crystalline state. It is impossible, however, to obtain the crystals quite free from all impurities. Hittorf's phosphorus can be prepared by sublimation if the differences of temperature in the different parts of the apparatus are made as small as possible. The density of Hittorf's phosphorus is less than that of ordinary red phosphorus, and there are differences in the chemical properties; for instance, ordinary red phosphorus reacts far more readily than Hittorf's phosphorus with sulphur, and the same difference is observed when they react with sulphur and iodine dissolved in carbon disulphide. Hittorf's phosphorus slowly oxidises in the air, while ordinary red phosphorus undergoes a fairly rapid oxidation in air, differing from white phosphorus only in the rate at which the reaction occurs. Reduction of Iron Oxide by Hydrogen and Carbon Monoxide. -Siegfried Hilpert.-Attempts to reduce iron oxide with hydrogen give negative results, and when carbon monoxide is used as a reducing agent the iron obtained exhibits properties different from those of pure ferrum redactum. It is comparatively difficultly soluble in acids, and a gas containing much hydrocarbons is generated; hence it is probably a carburetted iron, possibly cementite. Thus the direct reduction of the oxide does not seem a favourable method for the preparation of the intermediate oxides of iron. NEWS Hexa-halogen Iridates.-A. Gutbier and M. Riess.When bromides of organic ammonium compounds are dropped into iridium chloride solution containing dilute hydrochloric acid, bromine escapes, and the corresponding hexachlorous iridate separates in the form of a red-brown crystalline precipitate. dilute hydrobromic acid, the liquid, which was originally red-brown, turns first yellow, then green, and then suddenly becomes dark blue, the chlorous salt being converted ue or black crystals, which dissolve in water and in hydrobromic acid to give a blue liquid. They are not so stable as the alkali hexabromous iiidates, and are much affected by light. If the chlorous salt is boiled with into hexabromous iridate. These bromous salts form dark Carbonium Perchlorates.-K. A. Hofmann and H. Kirmreuther. Perchloric acid forms crystalline compounds with nearly all derivatives of triphenylcarbinol, and in the case of the strongly basic members of the fuchsine group dilute aqueous perchloric acid will precipitate the crystalline perchlorates, even from very dilute solutions. The authors have prepared hydrated triphenylcarbinol perchlorate, (C6H5)3C(OH2). CIO4, and the corresponding anhydrous substance, (C6H5)3C.O4Cl. Also phenolphthaleïn perchlorate, C20H1404-CIO4.H2O ; Aluoresceïn diperchlorate, C20H1205.2CIO4H ; and dibenzalacetone perchlorate, C17H140.CIÒ4H. The affinity of perchloric acid for carbinols, calculated to equal equivalents, is double that of sulphuric acid; thus, to form salts about twice as much by weight of sulphuric acid as of perchloric acid is needed. MONDAY, 28th.-Royal Society of Arts, 8. (Cantor Lectures). "The Petrol Motor," by Prof. W. Watson, D.Sc., F.R.S. TUESDAY, March 1st.-Royal Institution, 3. "The Emotions and their Expression," by Prof. F. W. Mott, F.R.S. Royal Society of Arts, 4.30. "Fruit Production in the British Empire," by Dr. John McCall. WEDNESDAY, 2nd.-Royal Society of Arts, 8. "The Teaching of Design," by E. Cooke. Calcium Ferrites. Siegfried Hilpert and Ernst Kohlmeyer. When iron oxide prepared from oxalate and pure calcium oxide are fused together, and the meltingpoint curve off the mixture is examined, it is found that the melt with 95 per cent of lime contains the latter in the form of crystals, which decrease in amount as the proportion of iron increases, until they disappear at 75 per cent of lime. At 1410° calcium orthoferrite 3CaO.Fe2O3 is formed. When the percentage of lime has been decreased to 60 a maximum corresponding to 3CaO.2Fe2O3 THURSDAY, 3rd.-Royal Institution, 3. "Illumination, Natural and is observed, and as the proportion of iron is increased a eutectic occurs at 1200° corresponding to CaO. Fe2O3. The colour of the melts varies with the amount of lime present, those richest in iron oxide being black and metallic looking. Their conductivity is small. The calcium ferrites are attacked by water and dilute acids. Vol. xlii., No. 18, 1909. Action of Metals on Fused Caustic Soda.-M. Le Blanc and L. Bergmann.-When caustic soda is heated in a gold vessel to 400° in an atmosphere of dry nitrogen it is readily dehydrated, and gives up no more water when the temperature is raised to 720°. The average amount of water given up at 400° is 2'44 per cent. Evidently caustic soda does not dissociate at these temperatures according Gold has no to the equation 2NaOH = Na2O + H2O. action on dry fused caustic soda in absence of air between the above temperatures. Silver and sodium liberate hydrogen, while platinum, copper, iron, nickel, aluminium, zinc, and magnesium generate hydrogen, and water is simultaneously formed. This double reaction may be explained on the assumption that the metal-sodium oxide compound resulting from the reaction, Me + NaOH = Me(ONa)x, forms a complex compound with sodium oxide, and that then the reaction 2NaOH = Na2O + H2O can occur. The gold vessel, when heated with copper and caustic soda to 700°, yields an alloy which is not formed in absence of the alkali, and a gold-magnesium alloy has also been obtained similarly. Society of Public Analysts, 8. "Composition of Artificial" (Experimentally Illustrated), by Prof. Royal Society. 'Depression of Freezing-point in very Dilute Aqueous Solutions," by T. G. Bedford. "Sturm-Liouville Series of Normal Functions in the Theory of Integral Equations," by J. Mercer. "Solubility of Xenon, Krypton, Argon, Neon, and Helium in Water," by A, von Antropoff. Chemical, 8.30. "Phenomena observed when Potassium Mercuric Iodide is Dissolved in Ether and Water," by J. E. Marsh. "Relation between Absorption Spectra and Chemical ConstitutionPart XIV., The Aromatic Nitro-compounds and the Quinonoid Theory," by E. C. C. Baly, W. B. Tuck, and Miss E. G. Marsden. "Action of Ethyl Cyanoacetate on 5-Chloro-1 : 1-dimethyl-A4cyclohexene-3-one," by A. W. Crossley and C. Gilling. Constitution of Carpaine," by G. Barger. Optically Active Glycols derived from 1-Benzoin and from Methyl -Mandelate," by A. McKenzie and H. Wren. "Colour and Constitution of Azo-compounds," by J. T. Hewitt and F. B. Thole. "Direct Union of Carbon and Hydrogen at High Temperatures," by J. N. Pring. Affinity Relations of Cupric Oxide and 3: of Cupric Hydroxide," by A. J. Allmand. Amino Quinoline and the Colour of its Salts," by W. H. Mills and W. H. Watson. "Absorption Spectra of p-Toluidine, m-Xylidene, and their Condensation Products with Acetaldehyde," by J. E. Purvis. "Supposed Case of Stereoisomeric Tervalent Nitrogen Compounds," by H. O. Jones and E. J. White. FRIDAY, 4th.-Royal Institution, 9. Chree, F.R.S., &c. SATURDAY, " "Magnetic Storms," by Charles "Electric Waves and the Electro-magnetic Theory of Light," by Prof. Sir J. J. Thomson, F.R.S., &c. 5th.-Royal Institution, 3. Determination of the Ratios SrCl2: Ag2 and SrCl2 : 2AgCl. THE general method of procedure as regards strontium chloride was similar to that described in the case of the bromide. A quantity of the pure dry chloride was heated, first in a stream of nitrogen and then in a stream of hydrogen chloride, made by dropping pure sulphuric acid upon pure sodium chloride, until the strontium chloride fused, when the hydrogen chloride was displaced by nitrogen, and subsequently by dry air. The fused chloride was ice-like in appearance, and dissolved in water to a perfectly clear and neutral solution. The rest of the procedure was precisely similar to that employed in the case of the bromide. The solution of strontium chloride used in the titrations contained 0.0003384 grm. SrCl2 per cc.; the silver solution was the same as that previously employed. The fused silver chloride was always transparent and nearly colourless. Re-fusion never affected the weight by more than o'02 mgrm. The weight of the silver chloride obtained needed an additive correction for the amount of the salt present in the solution and wash-water drawn off. Determinations of the solubility of silver chloride in water have been made by Kohlrausch and Rose (Zeit. Phys. Chem., 1893, xii., 242), Böttger (Zeit. Phys Chem., 1903, xlvi., 602), and Kohlrausch (Zeit. Phys. Chem., 1904, 1., 356) with fairly concordant results. Richards (Fourn. Am. Chem. Soc., 1905. p. 486) has shown that the amounts are not sensibly affected by the presence of nitric acid, and according to Mulder (Seidell's 'Solubilities of Inorganic and Organic Substances," P. 285; also Comey's "Dictionary of Solubilities," p. 372) the nitrates of the alkalis and alkaline earths are without influence at ordinary temperatures. The mean amount at ordinary temperatures (18° to 20°) deduced from the various observations is 152 mgrms. per fire, and this value has been made use of as the basis of the Correction. The results obtained with the strontium chloride are given in Series C and D. In order to obtain an independent check upon these determinations of the atomic weight of strontium, two further series of estimations were made depending on the ratio of SrSO, to SrCl2 and SrBr2 respectively. The sulphuric acid needed to convert the halides into strontium sulphate was prepared by distilling "pure" sulphuric acid in a platinum apparatus, the middle third only of the distillate being employed. It was preserved in a platinum bottle. The strontium salts used were portions of the material of which the preparation has already been described. They were fused in a stream of hydrogen bromide and chloride series. respectively, and otherwise treated as in the preceding The weighed portions of the fused salts were transferred to a short wide burette-shaped vessel of about 75 cc. capacity, fitted with a fine delivery tube provided with a stopcock, and were then dissolved in pure warm water. About one and a quarter times the equivalent amount of * A Paper read before the Royal Society, January 13, 1910. sulphuric acid diluted with water was next placed in a tared porcelain crucible, and both solutions were heated nearly to the boiling-point. The solution of strontium salt was allowed to flow very slowly and in a thin stream into that of the sulphuric acid which was kept constantly agitated. In this manner the strontium sulphate was precipitated as a fine granular powder. If strong solutions of strontium salts are precipitated with dilute sulphuric acid in the cold, the strontium sulphate separates out as a gelatinous mass which, on heating, gradually shrinks, and becomes granular. By operating with hot solutions in the manner described, the danger of occluding undecomposed halide in the gelatinous precipitate is practically obviated. The contents of the crucible were next brought to dryness, first by means of superheated steam under a bell-jar, and subsequently in a glass air-bath heated to 220° until no further evolution of acid vapours could be detected. The dried mass was then gradually heated to bright redness, together with its tare for about two hours, cold, the strontium sulphate was moistened with 5 cc. of in a Meker furnace fitted with a silica muffle. When dilute sulphuric acid, dried, and again heated with the tare for an hour in the muffle, and after standing for about eighteen hours in the desiccator over phosphoric oxide weighed with the usual precautions. Both the crucible and its tare were again heat in the muffle and re-weighed, but no alteration in weight could be detected. In reducing the weights to a vacuum the specific gravity of strontium sulphate was taken as 3.91, being the mean value of four concordant determinations made on the substance after having been heated to redness. The atomic weight of S was taken as 32:07. The results are given in Series E and F. It is to be observed that even when using quantities up to 10 grms. in Series E and F an error of o'i mgrm. affects the value of the atomic weight to the extent of oor unit. Moreover, the vessels to be weighed are much larger in volume, and this affects the degree of accuracy with which The manipulative process, too, weighings can be made. is more complicated, and is attended with more numerous sources of error. As regards the effect of the occlusion of possibly undecomposed halide, it may be pointed out how this acts in the case of the two salts. In the case of the bromide, since 2Br = SO4 and 159.83 = 96 07, the effect of undecomposed bromide would be to increase the apparent weight of the sulphate, and thereby increase the value of the atomic weight; whereas, in the case of the chloride, since 2CI = SO4 and 70·9296'07, the effect would be to decrease the apparent weight of the sulphate, but this decrease would also increase the atomic weight. It is conceivable, too, that some reduction of the strontium sulphate might have taken place owing to the difficulty of altogether excluding atmospheric organic dust, in spite of the care taken in the evaporation. This dust would be charred by the sulphuric acid at 220°, and, on ignition, might reduce traces of the sulphate. The second treatment with sulphuric acid was intended to remove any possible trace of sulphide in the weighed sulphate. It should be stated also that the atmosphere of the Meker furnace was wholly oxidising, and no alteration of weight was found to occur as the result of successive heatings each of an hour's duration. probably mainly due to mechanical loss, arising, in spite of every precaution, from "spitting" in the course of the evaporation and ignition. The variations in the individual experiments are most As regards possible error in the calculation of the true weight of the finely divided strontium sulphate in vacuo, due to possible occlusion of air, we have no valid data for its estimation. But considering the nature of this salt, the error due to this cause must be very small, if not altogether NEWS THE CHEMICAL EXAMINATION OF ASPHALTIC MATERIAL. By S. W. PARR, BRAINERD mearS, and D. L. WEATHERHEAD. No. of experiment. SERIES D.-Ratio SrCl2: 2AgCl. 87.642. THE asphalt products of the United States have increased in value from six hundred and seventy-five thousand dollars in 1898 to nearly three million dollars in 1907, and the accompanying increase in the use of material by municipalities, together with the fact that the substances are mixtures and offer temptation for adulteration, has led to frequent demands for ratings and analyses. On attempting to comply with these requests, we have encountered serious obstacles. Most of the specifications for contracts and methods of analysis have been worked out, and depend upon the presence of Trinidad asphalt in the product, and seem to be unsuited for the mixtures prepared in the middle and western part of the United States. These very frequently contain gilsonite tempered with petroleum residues of either an asphaltic or paraffin base, or both, and, while often not complying strictly with the specifications, are undoubtedly good mixtures for the purposes for which they are prepared. Setting aside the physical tests, which are of great importance, and which must be made in judging any asphaltic mixture, and turning our attention to those methods which are based on extraction with organic solvents, and which are intended to give light on the quantity and properties of the chemical constituents, we find the methods in use most unsatisfactory. They are time consuming, expensive, and, owing to the changing specific gravity of the solvents used, do not furnish the concordant results desired. It accordingly seemed necessary, despite the numerous efforts of other investigators, to improve, if possible, the method of attack at this point. In 1907, Mr. W. H. Leverette, working in this laboratory, started on a plan of analysis differing from the older methods of extraction, the principle being to dissolve the bitumen as completely as possible and successively precipitate out the significant portions with partial solvents. It is along this line of procedure that the following investigations have been carried on. Experimental. With a view of obtaining the most complete solvents, experiments were carried out on a sample of practically ash-free gilsonite with chloroform, carbon disulphide, carbon tetrachloride, hot turpentine, benzol, and toluol. From these carbon disulphide was selected as the most suitable. After considerable experimentation, the method resolved itself into the following procedure:-Half-grm. samples of the powdered gilsonite are placed in separatory funnels of about 225 cc. capacity, and dissolved in 5 cc. of carbon disulphide. When complete solution has taken place, 100 cc. of hexane (sp. gr. 0.6516) are added, which precipitates a substance termed Precipitate No. 1, and which corresponds to the "asphaltene" of the usual methods. After standing two hours the mixture is filtered on a specially prepared Gooch crucible (B. Mears, Journ. Ind. and Eng. Chem., i., 477), which is dried in an airbath to constant weight at 105° C. This procedure was permissible as experimentation showed that no oxidation of the precipitate took place. The precipitate calculated in percentage of the sample was termed Precipitate No. 1. Experiments carried on with freezing mixtures, and also tests to determine the effect of boiling on the hexane mixture, were found unsatisfactory, as precipitation seemed incomplete and variable under these conditions. Shaking and standing longer than two hours before filtering were shown to have little beneficial action. In obtaining Precipitate No. 2, the filtrate from the preceding determination is evaporated to dryness in a separatory funnel on a water-bath, the hexane recovered by condensation, and the residue taken up with 10 cc. of |