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of Priestley and of Scheele on the composition of the atmosphere, gets by quick stages to comparatively recent times, and gives a very readable account of many of the steps in connection with the discovery of the inert gases. The following passage is interesting xhether we agree with i t or n o t : ‘‘ ITe consider i t probable t h a t the emanation, which has proved indifferent to all chemical reagents, is to be included in the list of the noble gases. If this assumption is correct the emanation must have a high atomic meight for in this group there are only tTVo vacant places; one mith the atomic weight 1 2 8 4j = 173, and one with the atomic w i g h t 128 C 90 = 218. SOK i t semis probable that, if an element should under a n y circumstances acquire the power to decompose, its decomposition products would be elements of the same group. Since helium, neon, and possibly argon are among the gaseous decomposition products of the emanation, since the decomposition is not changed b y water, copper sulphate solution or anything, and since lithium is probahly one of the products of a copper sulphate solution which has been exposed to the emanation, i t seems not impossible t h a t in the first case only a portion of the emanation yields such products as helium and neon while a much larger fraction, about g2 percent of the whole amount, serves as a source of energy. , . . .” TI.ilder D . Bancrojt
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La Rdfractom6trie et ses Applications Pratiques. B y D. Sidersizy. (Encj,clop&die scientifque des Aide-.\l&nto?‘re publike sous la direction de -11, L&autP.) 12 X 19 cm; p p . 172. Paris: G a ~ ~ t h i e u - l ~ i l l a rPrice: s. paper, 2.50 jvancs; bound. 3 fmncs.-In the preface the author says: “ T h e determination of the index of refraction of liquids has assumed considerable importance in the last few years and the refractometer has become of great use to the chemist. Just as fast as the physicists and the manufacturers have improved their instruments, making them more accurate, the chemists have increased their investigations in regard to all possible indices of refraction in order to use these constants in the analysis of organic siibstances and especially in determining cases of adulteration in cases where the ordinary methods of chemical analysis often fail. “ l y e have thought t h a t i t xould be useful to combine in a volume of the Encyclop&die scieiztifique des dzde-.lJ&?noire the most striking of these investigations and improvements, pointing o u t first the theory of refraction, then the different methods used for the determination of the indices, and lastly the practical applications to analytical chemistry.” The headings of the chapters are as follows: refraction of light; determination of index of refraction; new refractometers; practical applications of refractometry; numerical tables. In the last chapter, there are tables giving d a t a for glasses, solids, liquids, oils, f a t t y substances, essential oils, gases and I I ~ i l d c rD . Bancrojt vapors. Polarization et Saccharimbtrie. Bj, D . Sidersk?i. Encj,clop&dieScientifique des A i d e - . l I h o i r e , publike sous la direction dc .\I. L&aut&. Deumiime e‘dition, r e w e et auggment&e. 12 X 19 cm; p p . 168. Pavis: Gauthzer-I.’illors; .llasson ct Cz’e.-In the preface to the second edition the author says: “Since the appearance of the first edition many experimental d a t a have been collected in regard to the rotatory p o m r of organic substances and these
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d a t a necessitate a modification of some matters previously given. I have taken account of this, so far a s possible, by revising the values given in the tables of specific rotatory powers. I have added a table of multirotations and I have changed tlie different saccharimetric tables, basing them on the new official standard xeight of 16.29 adopted in French saccharimetry. “ I n the descriptive part I have called attention to some new forms of a p paratus a s well as to improvements in old forms. I n the analytical part I have indicated the new methods of analyzing sugar beets, commercial glucoses, etc. h new chapter has been added to shoiy the use of the rotatory power a s a means of analyzing some interesting substances containing alkaloids or other optically active compounds.” ll’ilder D . Bancyoft Explication mecanique des Propridtes d e la Matisre, Cohdsion, Affinit6, Gravitation, etc. B y A . Despauz. 14 X 23 c m ; p p . 3.52. Paris: Felix Alcan, 1908. Price: paper, 6 jrancs.-The author starts with the hypothesis of a helicoidal molecule and discusses the molecular constitution of matter; the energies and properties of matter due to tlie rotation of the molecules; the energies and properties of matter due to the translatory motion of the molecules ; chemical affinity ; gravitation ; hypnotic suggestion, and various other matters. As is often the case in books of this class, the author is not very careful in regard t o his facts. On p. I I O he states that a layer of oil keeps water from evaporating because the oil is impermeable to water. .is a matter of f a c t the partial pressure of water vapor is practically not afiected hy the oil a t all, provided we Tyait until equilibrium is reached. H e also claims t h a t air cannot pass through oil to \Later. though the fallnc?- of this \\as sho\\-n in Ostvald’s laboratory over t w n t y years :igo. On 11. 160 DeSaporta is quoted a s the autliority for the statement that no molecule \\-it11 more than txelve atoms can exist as vapor; being so heavy it is decomposed b y heat. I t is evident thnt tlie author has never distilled toluene. On p. IC)+ i t is stated that a coplier sulphate solution is the best electrolytic conductor known. The author rejects tlie electrolytic dissociation theory entirely, 11. 105, H e looks upon the current as an independent thing which starts t h e positive radical corkscrewing through the solution. S o distinction is made between the transference i ) f t h e ions Iiy the current anti the lilienomenon of electrical endosmose. of course such :I ciuantitative relation as T:ara.rlay’s l a x does not aI)peal 1 1. ildw il. linnrloit to the author :is being ( i f a n y irril)ortance. Untersuchung und Nachweis organischer Farbstoff e auf spektroskopischen Wege. Bj* j n r u s l a v / ~ o ~ i x d ) t c uk i i t i Y .‘\Iit:L,irku)tg I O U Ezcgcii G r a n d m v u g i i z . pL&tc, i~ollstiindig ~ r i ~ i g c i l r b c i t c ~t tfiet d x r - i i z ~ ~ i i v-4 ti~ ttjlugc. Ersfcr 7 e d . r6 7; 24 o n ; pp. riii 1 257, lietiin; ,jiilizc> .Sfi~-zflgir . ryo8. I’ricc~: p a p c r , 12 nlnrks.-A s the title slio\ys. tlie author advocates ~ l i cuqe of the spectroscope in the investigation and determination (of ilrganic dyes ( )rdinary methods of analysis are nothing like S)I satisfactory \\-hen it comes I o identifying the Same dye sold under different names or when it is a marter of detecting impurities or adulterations. I n cases where the absorption spectra of t i y o dyes are very similar under ordinary condition.;, tlie use i i f ;inother sillvent will often cause :i suflicient
