THE POPULAR SCIENCE MONTHLY FOR JUNE 



opens with an article on " Preventive Inoculation" by Dr. W. M. Haffkine, describing his discovery of 

 inoculation against the plague, said to be as important as Jenner's discovery of vaccination against small- 

 pox. Two timely topics are taken up in the article on "Colonies and the Mother Country " by James 

 Collier of Australia, and on the "Future of the Negro in the United States" by Professor Shaler of 

 Harvard University. Professor Davis, also of Harvard University, tells of the progress of physical 

 geography during the present century. The New Ymk Botanical Gardens, recently established, but 

 rapidly becoming one of the greatest gardens in the world, are described by the assistant-director, Dr. 

 D. T. MacDougal. Huberts. Wynkoop's article on "(las and Gas Meters " and Prof. Harold Jacoby's 

 article on the " Sun's 1 lestination " will interest every one. An article by Charles Darwin, containing obser- 

 vations on the development of his infant, which were made sixty years ago and are practically unknown, is 

 reproduced. Among other articles is one on the Penycuik experiments on telegony, that is the effect of a 

 sire on the offspring of a female mated with a subsequent sire, and one on Professor Loeb's discovery 

 that eggs may be made to develop chemically without the male element. 



THE POPULAR SCIENCE MONTHLY FOR JULY 



opens with an article, the first of a series on "The Stars" by Pro!'. Simon Newcomb, one of America's 

 greatest men of science. It also contains an illustrated article on " The Recent Solar Eclipse " by Dr. 

 S. P. Langley, who perhaps ranks next to Professor Newcomb as an American astronomer. Dr. II. ('. 

 Bolton describes the remarkable discovery of substances that give out light and Rpntgen Rays even after 

 being kept for years in the dark. Next to the advances in preventive inoculation, a second article on which, 

 by Dr. Haffkine, is printed in this number, the most important recent medical discovery is the relation of 

 malaria and mosquitoes, which is reviewed by Dr. P. Manson, whose work on this subject is of such 

 importance. The number also contains an elaborately illustrated article on " Technical Education in the 

 Massachusetts Institute of Technology" by Prof. George F. Swain of the Institute, on the " Psychology 

 of Crazes" by Prof. G. T. W. Patrick, on the "The Earth's Development in the Eight of Recent 

 Chemical Research " by Prof. Edward Renouf of the Johns Hopkins University, and on "Washington 

 as an Explorer and Surveyor" by Dr. Charles D. Walcott, Director of the U. S. Geological Survey. 

 Among other articles is a severe criticism of Mr. Tesla's alleged inventions published in the June Century. 



THE POPULAR SCIENCE MONTHLY FOR AUGUST 



opens with the presidential address before the American Association for the Advancement of Science by 

 G. K. Gilbert, describing the methods which have been used to determine the age of the earth. Professor 

 Newcomb contributes the second of his series on " The Stars." General Greely, who ranks next to Nansen 

 as an Arctic explorer, gives an account of the scientific results of Nansen's North Polar l^xpedition, 

 which have just become accessible. Professor Wood describes his experiments on the photography of 

 sound which he recently by special invitation presented before the leading English scientific societies. 

 Mr. Havelock Ellis, the eminent English man of science and author, contributes an article entitled " The 

 Psychology of Red." There are, among other contributions of timely interest, an elaboratelv illustrated 

 article on " The Automobile " by Mr. William Baxter, and the number contains, as always, a large number 

 of reviews and notes describing the most recent scientific publications and advances of discovery. All the 

 numbers are fully illustrated. The three mentioned above have as frontispieces portraits of three distin- 

 guished American men of science: Dr. Wolcott Gibbs, President of the National Academy of Sciences; 

 G. K. Gilbert, retiring president of the American Association for the Advancement of Science, and 

 Prof. R. S. Woodward, President of the American Association for the Advancement of Science. 



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