METEOKOLOGY. 457 



and German, an excellent text-book on earthquakes, by Professor Heim, 

 and have received a great mass of information in reference to the earth- 

 quake of December 29 to 31, 1879. Forel states that it consisted of three 

 chief shocks and a dozen small ones. The first strong shock was experi- 

 enced over an ellipse 200 miles long and 100 miles wide, whose axis was 

 parallel to the main chain of the Alps. Its intensity at Geneva reached 

 7 on the scale of 10 proposed by Forel. The accurate observation of 

 time, intensity, and direction of shock is the one thing necessary in order 

 to advance our knowledge of the sources and causes of earthquakes. 

 {Mature, XXY, p. 251.) 



Prof. John Milne, of the Imperial College of Engineering, Tokio, has 

 read before the Seismological Society of Japan a paper on the distri- 

 bution of earthquakes in Japan. His work is based on observations of 

 very many correspondents throughout Japan. He shows in a remark- 

 able manner how a large mountain range absorbs earthquake energy, 

 and again if instruments of ordinary sensitiveness could be used through- 

 out Japan there would be on the average at least 1,200 earthquake 

 shocks per year. {Kature, xxv, pp. 613, 614.) 



Professor Milne publishes in the Japan Gazette a Japanese earth- 

 quake chronology extending from 295 B. G. to 1854 A. D. Notwith- 

 standing the frequency of earthquakes in Japan the native chroniclers 

 have always carefully recorded them. [Nature^ xxvi, p. 17.) 



Professor Milne says that, in 1879, he commenced a series of experi- 

 ments with pendulums, microphones, and other apparatus, and special 

 pains were taken to insure that the noises recorded were due to actual 

 earthquakes, since the apparatus was so sensitive that a small pebble 

 dropped upon the grass at a distance of several feet was easily heard 

 in the telephone and recorded by a swing of the needle of the galva- 

 nometer. In fact, one of these pieces of apparatus was converted into 

 a "thief detector" by arranging it so it rang a bell whenever tremors 

 were produced by the footsteps of persons passing through the yard. 

 The Japanese observers seemed to be animated by the hope that the 

 study of these small tremors will ultimately enable them to predict the 

 larger and more important ones. {Nature, xxvi, p. 125.) 



In a report on the earthquake phenomena of Japan, Professor Milne 

 states besides the several seismic centers within that island there are 

 also several in the open sea outside that island. He describes the re- 

 sults of experiments as to artificial earthquakes, namely, the explosion 

 of dynamite, the falling of a heavy iron ball, &c. {Nature, XXYI, p. 464.) 



