February 11, 1898.] 



SCmNGE. 



215 



■which does not, there is no question but that 

 we should take up next the case of a substance 

 which dissociates into a vapor and a liquid or 

 a vapor and a solid. An instance of this last is 

 calcium carbonate, which dissociates on heating, 

 forming carbonic acid and calcium oxide. This 

 is a two-component system, but it has been de- 

 rived from a one-component system by heating, 

 and is therefore discussed by Duhem. This is 

 a very ingenious way of attacking the subject, 

 and has the great merit that the transition 

 from one to two components is made gradually 

 and not abruptly. It has the disadvantage 

 that one has to cover this intermediate ground 

 a second time when studying two-component 

 systems. What Duhem has done is to consider, 

 in this volume, systems such that the sum total 

 of all the masses in all the phases can be repre- 

 sented by the chemical formula for a compound. 

 The book is divided into three parts, the first 

 of which includes saturated vapors, the phenom- 

 ena of boiling, change of freezing point and 

 equilibrium between solid and solid, dissocia- 

 tion curve for two solids and vapor, the triple 

 point and the curves meeting in it. The second 

 part of the volume deals with the continuity 

 between the liquid and the gaseous states, while 

 dissociation in the vapor phase is taken up in 

 the closing section. Of special interest are the 

 chapters on the phenomena of boiling, on ap- 

 parent false equilibrium as applied to boundary 

 curves, on dissociation in gases and on the 

 theory of false equilibrium. The book at- 

 tempts, in an admirable manner, to present 

 exact theory in such a form as to be applicable 

 to experimental data and not to hypothetical 

 or simplified phenomena. Of course, this is a 

 goal which no treatise can hope to attain at the 

 present time ; but this volume of Duhem's 

 comes nearer to it than anything that has yet 

 been published. It is not too much to predict 

 that the whole study of organic chemistry will 

 be revolutionized as soon as the points of view 

 suggested by Duhem become well understood. 

 All the phenomena connected with isomerism 

 become capable of quantitative treatment as 

 soon as they are studied experimentally with 

 reference to the theory of false equilibrium and 

 the theory of permanent changes recently de- 

 veloped by Duhem. It seems probable that it 



will be possible, by application of these same 

 two theories, to make an intelligent study of 

 all chemical reactions not involving more than 

 four components. 



Wilder D. Bancroft. 



SOCIETIES AND ACADEMIES. 

 THE PHILOSOPHICAL SOCIETY OF WASHINGTON. 



The 478th meeting of the Society was held 

 at the Cosmos Club at 8 p. m., on January 22d. 

 Two papers were presented : The first by Dr. 

 Walter Hough' on the 'Origin and Range of 

 the Eskimo Lamps.' The conclusions reached 

 were : That the Eskimo before he migrated from 

 his pristine home had the lamp, this utensil be- 

 ing a prerequisite to migration into high lati- 

 tudes. That one of the most important func- 

 tions of the lamp is for melting snow and ice 

 for drinking water. That the lamp is employed 

 for lighting, warming, cooking, melting snow, 

 drying clothes and in the arts, thus combining 

 in itself several functions which have been dif- 

 ferentiated among civilized peoples. That the 

 architecture of the house is related to the use 

 of the lamp. The house is made non-conduct- 

 ing and low in order to utilize the heated air. 

 That the lamp is a social factor, peculiarly the 

 sign of the family unit, each head of the family 

 (the woman) having her lamp. That the inven- 

 tion of the lamp took place on some seacoast, 

 where fat of aquatic mammals of high fuel 

 value was abundant, rather than in the in- 

 terior, where the fat of land animals is of low 

 fuel value. That the typical form of the lamps 

 arises from an attempt to devise a vessel with 

 a straight wick edge combined with a reservoir 

 giving the vessel an obovate or ellipsoidal 



Finally, from observation of lamps from 

 numerous localities around the Eskimo shore- 

 line, it is concluded that lamps in low latitudes 

 below the circle of illumination are less special- 

 ized than those of higher latitudes. For in- 

 stance, the lamps of southern Alaska have a 

 wick edge of two inches, while those of Point 

 Barrow and northern Greenland have a wick 

 edge of from 17 to 36 inches in width. It be- 

 comes possible, then, to say with some cer- 

 tainty the degree of north latitude to which a 

 lamp appertains, light and temperature being 



