248 Scientific Intelligence. 



determine, but enough variations in the absorption have been 

 observed to indicate that the Observatory is now in condition to- 

 make advances along the line indicated in the Secretary's Report 

 for 1892, in which is pointed out the important relations of astro- 

 physics to meteorology. 



2. Physical Geography ; by William Morris Davis; pp, 

 xviii, 428, with nine plates, etc. Boston, 1899 (Grinn & Co.). — 

 This volume has the necessary elements of a high grade text- 

 book : it is scientifically accurate, contains no unnecessary matter 

 and is written in a pleasing manner. The earth's features are not 

 only described, they are exj)lained, and the reader is led to see a 

 rational meaning in the varied land-forms about him. The 

 student is constantly reminded, also, of the way in which phys- 

 ical features and climate have influenced man in his settlements, 

 industries and manner of life. 



The illustrations deserve special praise both in their selection 

 and mechanical execution. The numerous " block-diagrams " are 

 particularly valuable. Education in general and the out-of-door 

 sciences in particular will be benefited by the introduction of just 

 such text-books into secondary schools. h. e. g. 



3. The Annual Report of the Director of the Field Columbian 

 Museum to the Board of Trustees, for 1897-98. Report Series, 

 Volume I, No. 4. Chicago, October, 1898. — This Report gives an 

 interesting summary of the work of the Field Columbian Museum 

 for 1897 and 1898. The numerous illustrations introduced give 

 views of many of the rooms with their collections, and also of 

 some of the objects of particular importance. 



OBITUARY. 



Prof. Louis W. Peck, for several years of the department of 

 Physics in the University of Minnesota, died in Tucson, Arizona, on 

 December 26th, in the 47th year of his age. He was born in Provi- 

 dence, R. I., and was educated in the Mass. Institute of Technology. 

 He also served an apprenticeship in the Harris Corliss Engine Works 

 in Providence. Prof. Peck's contributions to science were made in 

 the investigation of the flouring mill explosion that occurred in 

 Minneapolis, Minn., May 2, 1878. The mills exploded and then 

 burned. They were insured against loss by fire and it became a ques- 

 tion of great importance whether fire caused the explosion or the 

 explosion caused the fire. Prof. Peck contrived a simple appara- 

 tus by which he showed that flour and wheat dust, when mixed 

 with air in suitable proportions, would explode with terrific force 

 if ignited with flame. Glowing charcoal and white hot platinum 

 wires would not ignite the mixture, hence the conclusion was 

 inevitable, confirmed by collateral evidence, that the mills were 

 on fire before they exploded. Prof. Peck's results were embodied 

 in a paper which was published in the Popular Science Monthly, 

 xiv, p. 159, and the London Journal of Science, xvi, p. 666. This 

 paper was widely copied and reviewed. s. f. p. 



