902 



SCIENCE 



[N. S. Vol. XXVI. No. 678 



ments and patient manipulation that could 

 he devised, the result being a value for 

 Joule's equivalent which at once acquired 

 authority in the light of the evidence pro- 

 duced, and largely confirmed the correc- 

 tions already advanced by Rowland and 

 others. A main cause of discrepancy had 

 been found to be the variation of the ther- 

 mal capacity of water with the tempera- 

 ture ; and by an investigation in which this 

 variation was determined, Griffiths eluci- 

 dated and correlated fundamentally the 

 work of previous observers, from Joule 

 onward. Of special importance also, in 

 the domain of chemical physics, was an 

 investigation of the depression of the freez- 

 ing point of water by very dilute admix- 

 ture of dissolved substances, wherein he 

 verified, with all the refinement of absolute 

 physical determinations, that the change of 

 freezing point ran exactly parallel to the 

 electric conductivity when the dilution of 

 the electrolyzable salt was comparable to 

 that of gases, being twice as much per 

 molecule as the standard value of the de- 

 pression for non-electrolytes. 



The Buchanan medal is awarded to Mr. 

 William Henry Power, C.B., F.R.S. Mr. 

 Power's services to hygienic science and 

 practise have extended over a period of 

 more than thirty years, and have been of 

 the most distinguished kind. He has him- 

 self personally conducted successful in- 

 quiries into the causes of the spread of 

 various diseases, and has obtained results 

 which have proved of the greatest benefit 

 to mankind. Moreover, in his long connec- 

 tion with the medical department of the 

 Local Gpvernment Board he has planned 

 and directed numerous general and local 

 investigations whereby our knowledge of 

 disease, and of the methods of coping with 

 it, have been greatly increased. The med- 

 ical reports issued by the Local Government 

 Board, which are universally regarded as 

 among the most important contributions 



of our time to this subject, have for many 

 years past been either written by him or 

 owe much to his editorial criticism and 

 supervision. It is not too much to say that 

 no living man in this country has advanced 

 the cause of scientific hygiene more than 

 Mr. Power, or is more worthy of the dis- 

 tinction of the Buchanan medal. 



SCIENTIFIC BOOKS 

 Research in China. Volume I., Part 2. 

 Petrography. By Eliot Blackweldee. Car- 

 negie Institution of Washington, Washing- 

 ton. 1907. 



Eoeks from northern and central China are 

 described microscopically in this portion of 

 the report; their field relations and stratig- 

 raphy have been given in Part 1 of this 

 volume. The method of treatment is as in- 

 dividual specimens arranged according to 

 geographical distribution, that is, by districts 

 of which eleven are recognized. Their further 

 arrangement is by geological age, mode of 

 formation, and finally by petrographic char- 

 acter. The report is, therefore, a detailed 

 statement of observations and data, with little 

 attempt at general or comprehensive simi- 

 mary of results. The material collected is 

 not considered sufficient for such a treatment. 

 The Khin-Gan district of the mountain 

 range by that name in northwestern Man- 

 churia, so far as seen from the Chinese-East- 

 ern Railroad, appears to be made up largely of 

 igneous rocks. In addition to a gray biotite- 

 granite there are black quartz-porphyry, 

 hornblende-porphyry, feldspar-porphyry and 

 gray hornblende-granite. 



In the western portion of the Liau-Tung 

 peninsula in southern Manchuria the rocks ob- 

 served belong to several distinct systems : The 

 T'ai-shan gneissic complex; the Ta-ku-shan 

 schists, quartzites and marbles; the Sinian 

 sedimentary series including quartzite con- 

 glomerate and psammites of Cambro-ordovi- 

 cian age, besides igneous rocks in dikes. These 

 are rhyolite porphyries, andesitic and basaltic 

 porphyries, more or less altered. 



In the neighborhood of Peking a small ridge 



