Chemistry and Physics. 81 



4. A Neio Variety of Chromium. — It has been observed by 

 Jassonneix that metallic chromium, or also this metal containing 

 boron or carbon, when heated in the electric furnace in contact 

 with much copper, gives a solution containing about 1*6 per cent 

 of chromium. Upon cooling, the chromium separates in a mossy, 

 crystalline condition, and this can be separated from the matrix 

 of copper by dissolving the latter in nitric acid. The product is 

 almost pure chromium in a very fine state of division. It is stable 

 in the air at ordinary temperatures, but it burns like tinder in 

 contact with aflame, and ignites in oxygen at about 300°, giving 

 a very brilliant incandescence. — Comptes Mendus, cxliv, 915. 



h. l. w. 



5. Memoir and Scientific Correspondence of the late Sir 

 George Gabriel Stokes. Selected and arranged by Joseph Lae- 

 moe. In two volumes, Vol. I, pp. xii + 475; Vol. II, pp. vi 4- 

 507. Cambridge, 1907 (The University Press). — From 1854 to 

 1885 Sir George Stokes was Secretary of the Royal Society and 

 had much to do with the scrutiny to which that society subjects 

 papers which are offered for publication in its transactions. He 

 performed these duties so carefully, with so much kindness and 

 critical acumen, and offered so many helpful suggestions to the 

 authors of papers that he gradually came to occupy the place of 

 adviser and friendly critic to most of the British physicists of his 

 own and of the younger generation. His correspondence was 

 thus very large and he saved all letters which came to him, so 

 that at his death more than ten thousand letters were found. 

 Out of this great number Professor Larmor has made a careful 

 selection and, in many cases, has been able to obtain Stokes's 

 replies, which are inserted in their proper places. We have the 

 result in the two volumes under review, which no student of 

 physics can read without keen delight and very great profit. 

 Stokes's life-time covered that great era of physical discovery 

 which (if second to any other) is second only to the time of New- 

 ton; he, and some of his correspondents, contributed more, prob- 

 ably, to these great results than any other group of men in any 

 country. And in these volumes we find the intimate, contempo- 

 rary history of this active time; we read the first informal 

 accounts of important discoveries, or of tentative and hesitating 

 speculations which have since become the classical theories of 

 physical science. One gets thus a feeling for historical perspec- 

 tive and an appreciation of how discoveries are made which could 

 hardly be obtained in any other way. Another thing which 

 comes out quite clearly, is the effect which Stokes's activity had 

 upon the progress of his science indirectly, through his advice 

 and assistance to others, and quite independently of his published 

 contributions. Many investigators have gratefully acknowledged 

 their indebtedness to him, and these letters show very clearly 

 that the gratitude was well-deserved. Lord Kelvin, in particu- 



A.M. Jour. Sci.— -Fourth Series, Vol. XXIV, No. 139.— July, 1907. 



