3/' 



NA TURE 



[August i6, 1906 



sufficiently developed lo grasp a certain trutli, because 

 truth is objective; but it is not proved to be objective 

 b\- the fact that it is recognised as true by a ' suffi- 

 ciently developed ' intellect. The objectivity of truth 

 lies in the recognition of facts as true by all who 

 understand them fully, whilst the appeal to a suffi- 

 cient knowledge assumes their objectivity." How any- 

 one can understand facts fully without sufficient know- 

 ledge it will puzzle the plain man to discover. And in 

 another passage he writes : " Far above the vulgar 

 idea that the right is a settled something to which 

 everybody has to adjust his opinions, rises the con- 

 viction that it has existence in each individual mind, 

 capable of any expansion, proclaiming its own right 

 to exist, if needs be, venturing to make a stand 

 against the whole world." This sentence seems to 

 the writer of this notice a huge mis-statement, or, if 

 true, true only in the sense in which the same 

 sentence must be understood with the words " the 

 truth" substituted for the words "the right." 



But to linger over the more controversial aspects of 

 such a book is always an ungrateful task. With the 

 rest of the work there is little fault to be found. The 

 account of the moral emotions, the treatment of 

 punishment (in which subtle arguments are offered 

 against determent as a sufficient guiding principle), 

 the discussion of the various distinctions suggested bv 

 terms like act, agent, motive, intention, the detailed 

 examination of the facts advanced by such authorities 

 as Lord .\vebury. Dr. J. G. Frazer, Dr. Steinmetz, 

 are all excellent. On the whole, Dr. Westermarck's 

 view of the condition of savage races is one flattering 

 to humanity — if not to civilisation. He points out 

 how much more brutal punishment has often been 

 ainong the civilised than among the uncivilised. He 

 believes in the "noble savage," and thinks that many 

 accounts of " savagery " among savage races come 

 from a time when they have been affected by a 

 "higher culture," a culture "which almost univers- 

 ally has proved to exercise a deteriorating influence 

 <in the character of the lower races." One would 

 like to see a monograph devoted to this subject, and 

 learn what the best missionaries have lo sav. 



JOSEPH PRIESTLEY. 

 Joseph Priestley. By T. E. Thorpe, F.R.S. English 

 Men of Science. Edited by Dr. J. Reynolds Green. 

 Pp. viii + 22,S. (London : J. M. Dent and Co., 

 n)()6.) Price 2s. 6d. net. 



T T is a curious and unaccountable fact that whilst 

 ■•- for more than fifty years we have been in posses- 

 sion of a biography of Cavendish, whose solitary and 

 uneventful existence was chiefly passed within the 

 tour walls of his laboratory, a whole centurv has 

 elapsed without the appearance of any worthy record 

 (if Priestley's life, which was so full of human interest 

 and dramatic incident. Following closely upon the 

 centenary commemoration of Priestley's death, the 

 new volume in the series of English Men of Science 

 comes as a fitting and welcome memorial. 



That the task should have fallen to Dr. Thorpe 

 NO. 1920, VOL. 74] 



seems perfectly natural and appropriate, and one 

 might feel assured beforehand that the writer of the 

 charming little biography of Humphry Davy, poet 

 and philosopher, would be equally happy in his treat- 

 ment of the present subject. These anticipations have 

 not been disappointed. The book is not for chemists 

 only. It will attract a wider circle of readers, and 

 will not fail to add to the literary reputation of its 

 distinguished author. 



No one has perhaps portrayed his own character in 

 his writings more graphically than Priestley. We 

 know the main events of his life from his own pen ; 

 we can study his opinions, religious, political and 

 social, in his numerous brochures; the records o.f his 

 chemical experiments vividly reflect his scientific habit 

 of thought. .Ml his writings express the same can- 

 dour and simplicity, the same virile honesty, which 

 were the keynotes of his character. 



Priestley has happily been allowed to tell his story 

 as far as possible in his own words, and the abstracts 

 from his memoirs, supplemented by others, notablv 

 Miss -Xikin's account of the life at the Warrington 

 .\cademy and Miss Russell's thrilling description of 

 the Birmingham riots, are skilfully woven into a con- 

 tinuous and delightful narrative. 



Chemists will naturallv turn with special interest 

 to the account of Priestley's scientific labours, and 

 here it must be confessed that the small space, 

 unavoidably, no doubt, allotted to this section is the 

 least satisfying part of the volume. 



The vast accumulation of experiments from their 

 discursive treatment and confused arrangement 

 would have repaid careful editing. But if we have 

 not everything, we have at least a substantial record 

 of what is most valuable among Priestley's dis- 

 coveries. 



Priestley was in a sense a follower of Hales. The 

 musket-barrel, the trough for collecting gases, the 

 burning-glass for heating substances in vessels stand- 

 ing over water, are described in the " Vegetable 

 .Staticks. " Hales, moreov'er, obtained oxygen, like 

 Priestley, by heating red lead in a gun-barrel, but he 

 never knew that the gas he so carefully collected and 

 measured differed from ordinary air. But if Priestley's 

 experiments were suggested by those of Hales they 

 served onlv as a foundation to build upon. The 

 improvement introduced bv Priestley into pneumatic 

 apparatus would alone have earned for him a lasting 

 reputation and the gratitude of subsequent generations 

 of chemists; but his great discovery was, of course, 

 the recognition of different kinds of air. 



As a theorist Priestley's claims are insignificant, for 

 he was particularly unfortunate in interpreting his 

 own observations. Dr. Thorpe says very truly : 



" The contrast between Priestley the social, political 

 .-md theological reformer, always in advance of his 

 times, receptive, fearless and insistent, and Priestley 

 the man of science — timorous and halting when he 

 might well be bold, conservative and orthodox when 

 almost every other active worker was heterodox and 

 progressive — is most striking." 



Equally striking is the absence of any well-con- 

 sidered plan in his method of experimenting when his 



