576 



THE POPULAR SCIENCE MONTHLY 



izing the county courts to employ competent 

 persons to fix the north and south lines at 

 the county-seats, at an expense of not more 

 than fifty dollars each. 



Recent experiments by Nies and Win- 

 kelman indicate that expansion, in passing 

 from the liquid to the solid state, is a more 

 common property of metals than has been 

 believed. Their fundamental experiment 

 consisted in putting the solid metal into 

 the liquid. In some cases the difference in 

 density could be measured. They found 

 that six out of eight metals examined dis- 

 tinctly expanded in solidifying, while the 

 result was obscure in the case of the other 

 two metals. Tin increased in volume 0'7 

 per cent. ; zinc, 0-2 per cent. ; bismuth, 3 

 per cent. ; and antimony, iron, and copper 

 in obvious proportions. Lead and cadmium 

 presented difficulties that hindered a satis- 

 factory determination of their qualities. 



Kraut has shown that ordinary combus- 

 tible substances may be set on fire by nitric 

 acid. A wooden box of convenient size was 

 half filled with sawdust, hay, straw, tow, or 

 shavings. A flask containing nitric acid, of 

 at least 1'5 specific gravity, was placed upon 

 this, and the box filled up with the combus- 

 tible material. The flask was then broken, 

 and a wooden cover was put on the box. 

 Vapors were seen in one or two minutes ; a 

 thick, white smoke appeared a little later ; 

 and the odor of the burning material was 

 observed. On opening the box a few min- 

 utes afterward, the interior was found all 

 on fire, and flames burst out. 



ir. E. ViLLARi, from experimental meas- 

 urements of the temperature of the body 

 during acts of motion, has reached the con- 

 clusions that the lowest temperature in man, 

 ensuing after a period of rest, is 98-4 ; that 

 the temperature increases, under the influ- 

 ence of a positive, ascending effort, to 

 100'G, under the influence of a descending 

 effort to lOO'S" ; that it increases after any 

 exertion, but more after an ascending than 

 after a descending one ; and that the chemi- 

 cal actions of the organism arc augmented 

 after every movement. 



A Sunday Science School at Edinburgh, 

 Scotland, has enrolled ninety-two pupils, and 

 enjoyed an average attendance, from Novem- 

 ber to July last, of sixty youth who "were 

 not able on account of late business hours 

 to attend the evening classes. 



]\I. PicTET recently read a paper before 

 the French Society of Civil Engineers, ex- 

 plaining the operation of his ice-rnachincs, at 

 the close of which he invited the members 

 of the society to visit his works, where two 

 machines are operating with sulphurous acid, 

 one of which produces 2,425 pounds of ice 

 per hour. 



The first number of Volume II of 

 " Studies from the Biological Laboratory 

 of John Hopkins University " is just pub- 

 lished, and contains among others a lengthy 

 but very interesting article on " The Study 

 of Human Anatomy historically and legally 

 considered." 



Mr. Ronald Campbell Gunn, a Tasma- 

 nian botanist, died March 14th, aged seventy- 

 three years. He was born at the Cape of 

 Good Hope, and, having removed to Tas- 

 mania in 1830, was intrusted with impor- 

 tant official positions. He began to investi- 

 gate the botany and natural history of the 

 island in 1830, and in this occupation ram- 

 bled over most of the colony. Reports of 

 his work appear in Sir Joseph D. Hooker's 

 "Flora of Tasmania," and in several periodi- 

 cal publications. He was also editor of the 

 *' Tasmanian Journal," a scientific publica- 

 tion. 



Almost simultaneously with the publica- 

 tion of the discoveries of Messrs. Bell and 

 Tainter in radiophony, M. Mercadier, in 

 Paris, without any knowledge of what they 

 had done, announced that he had been able 

 to reproduce the sounds of speaking and 

 singing upon the photophonic receiver, not 

 only with the light of the sun, but also by 

 means of the electric light, and the oxy- 

 hydrogen light. 



Mr. John Blackwall, one of the oldest 

 members of the Linnaean Society, died May 

 11th, aged ninety-two years. His principal 

 work was a monograph on the British spi- 

 ders, published by the Ray Society, about 

 twenty years ago. He also published " Re- 

 seaixhes in Zoology," in 1834 (second edi- 

 tion, 1873), and a considerable number of 

 papers on general zoology. 



A market for the sale of toads to gar- 

 deners is held regularly every week in 

 Paris. Dealers bring their " goods " in w^ell- 

 ventilated casks, in which the toads are 

 packed in lots of a hundred, in damp moss. 

 A lot of a hundred good individuals will 

 bring fifteen to seventeen dollars. The gar- 

 deners use them to keep down the destruc- 

 tive insects that annoy them. A Dutch 

 gardener, M. Krelage, of Haarlem, recom- 

 mends the use of the toad in greenhouses, 

 as furnishing an excellent means for de- 

 stroying the millcpeds that infest the plants. 



An International Medical and Sanitary 

 Exhibition is to be held under the auspices 

 of the Parkcs Museum of Hygiene at South 

 Kensington from July IGth to August 13th. 

 It will comprise everything that is of service 

 for the prevention, detection, cure, and alle- 

 viation of disease. 



The French Association for the Ad- 

 vancement of Science will meet at Rochelle 

 next year. 



