172 



SCIENCE 



[N. S. Vol. XL. No. 1022 



hands. They certainly owe to the author and 

 American pathologists a speedy revision. 



F. D. Heald 

 Zoology Building, 

 Univeksitt op Pennsylvania, 

 Philadelphia, Pa. 



A New Era in Chemistry. By Harry C. 



Jones. New York, D. Van Nostrand and 



Company. 1913. Price $2.00. 



It is expected of a hook written hy a teacher 

 and investigator so eminent as Professor Jones 

 that it will he written in a clear, enthusiastic 

 and readable style, and especially that it will 

 be scientifically accurate and sound. That the 

 book meets some of these expectations no one 

 can doubt who reads Professor Howe's very 

 laudatory review in the December number of 

 the American Chemical Journal. The present 

 reviewer, however, while recognizing merit in 

 the book, certainly believes that no author 

 should be permitted to go uncriticized who 

 is so careless of his statements as is the 

 author of " A JSTew Era in Chemistry." 



Among many other passages in the book 

 which are open to criticism the following have 

 been selected as representative. 



In discussing the formula for benzene on 

 page 12 the author says : " The study of the 

 substitution products led to the conclusion 

 that three carbon atoms in benzene are differ- 

 ent from the other three. . . ." Whatever 

 may be the final outcome of recent work in 

 this field, it is certainly well known that the 

 study of benzene and its substitution products 

 led neither Kekule nor any of his contempo- 

 raries to any such conclusion. 



On pages 51-52 is given an inadequate, even 

 quite erroneous, account of the stereochemis- 

 try of tartaric acid. The author writes, 

 " Tartaric acid is especially interesting, hav- 

 ing the constitution. . . . We see that it 

 contains not only one asymmetric carbon 

 atom, but two. These would have the opposite 

 effects upon a beam of polarized light; the 

 one half of the molecule turning it in one 

 direction, and the other half turning it by 

 an exactly equal amount in the opposite 

 direction. The result would be that the sub- 

 stance would be racemic or optically inactive." 



Certainly no one can get any clear conception 

 of the stereochemistry of tartaric acid from 

 such a description. 



Speaking, on page 63, of the one degree of 

 freedom in the two-phase-one-component sys- 

 tem, water and water vapor, the statement is 

 made that " we can vary either the tempera- 

 ture or pressure, but varying the one we fix 

 the other." And on the next page, in discuss- 

 ing the triple point, the author writes: "We 

 can not move the point T in any direction 

 without destroying the equilibrium. . . ." 



These are very careless statements, both 

 telling what does not take place. What the 

 author intends to say with respect to the 

 former is that a change either of the tempera- 

 ture or the pressure brings about a concomi- 

 tant change in the other. With respect to the 

 latter it may be noted that T, the triple point, 

 is a fixed point and therefore can not be 

 moved. A change of temperature or pres- 

 sure brings about the disappearance of one 

 of the three phases, but does not move the 

 point T. 



On page 281 we read, "It [radium] is 

 everywhere, also, in atmospheric air " ; and 

 on page 273 it is stated that the alpha par- 

 ticle " carries one positive charge of electric- 

 ity." Eadium apparently does occur nearly 

 everywhere, but its presence in the atmosphere 

 is yet to be demonstrated. The alpha particle 

 carries two charges, not one. 



The following, taken from pages 273, 277 

 and 287, are given as examples of careless 

 statements. No objections are raised con- 

 cerning what the author probably intended to 

 say : " Radium is naturally radioactive as it 

 is called." " A radioactive substance is one 

 that gives off radiations. . . ." " The best 

 method used was the ice calorimeter." " A 

 gram of radium therefore liberates about 

 eighty calories of heat every hour, during its 

 whole life history." " The largest amount of 

 radium emanation thus far obtained is only a 

 fraction of a cubic millimeter; and, yet, this 

 gives off three fourths of all the heat liberated 

 by radium." A gram of radium liberates 

 heat at the rate of " about " eighty calories 

 per hour so long only as it remains sensibly a 



