256 



THE POPULAR SCIENCE MONTHLY. 



on March 20th. He was born in 1814; 

 studied medicine at Tubingen and in Paris ; 

 in 1840 he visited the Dutch East Indies, 

 and while there was led to study the rela- 

 tion between heat and work. His first pub- 

 lication on this subject appeared in 1842. 

 In 1871 he was awarded the Copley medal 

 by the London Royal Society. 



The Colorado potato-beetle is reported 

 to have made its appearance in New Zea- 

 land, where it now exists in formidable 

 numbers in some localities. It appears to 

 have been introduced with some American 

 potatoes. 



At Borsigwerk, in Silesia, the experi- 

 ment has been successfully made of growing 

 mushrooms in a coal-pit, at a depth of 1 26 

 metres below the surface of the earth. The 

 fungi grow rapidly and plentifully in an 

 average temperature of 8 Reaumur. The 

 mushrooms so grown are said to be of finer 

 flavor than those developed in the open air, 

 and command higher prices. 



The line of an interoceanic canal across 

 the Isthmus of Darien, proposed by Ferdi- 

 nand de Lesseps, starts from the Pacific 

 coast, and ascends in the first place the 

 Tuyra River as far as the island of Piriaque ; 

 thence a straight cutting, 16,200 metres 

 long connects the Tuyra with the Chucana- 

 que ; the line then ascends the Chucanaque 

 for 11,400 metres; then, turning to the 

 northeast, it continues up the valley of the 

 Tiati, to a point where a tunnel appears to 

 be more economical than a very deep cut- 

 ting. The tunnel passes to the south of the 

 Peak of Gandi. On emerging, the canal 

 continues through an open cutting for about 

 ten kilometres to the deep waters of Port 

 Gandi. The probable length of the tunnel 

 is between thirteen and fourteen kilometres, 

 and the cost of making the whole canal is 

 estimated at 600,000,000 francs. This ship- 

 canal, if ever completed, will doubtless be 

 the most stupendous engineering work in 

 the world. 



It will be a surprise to most readers to 

 learn that Theodor Schwann, founder of the 

 " cell-theory " in biology, is still not only 

 living, but actually " in the traces." He is 

 Professor of Physiology in the University of 

 Liege, Belgium, and will soon complete the 

 fortieth year of his professorial life. It is 

 proposed to celebrate this noteworthy anni- 

 versary of the venerable professor by the 

 presentation to him of an address, signed 

 by prominent anatomists and biologists of 

 all countries. 



A company has been established in Par- 

 is for operating the system of pneumatic 

 clocks successfully adopted in Vienna, an 

 account of which was recently published in 

 these pages. 



Prof. Luvini, of Turin, has experiment- 

 ed upon the action of different gases, such 

 as pure atmospheric air, oxygen, hydrogen, 

 carbonic acid, chlorine, and sulphurous acid, 

 on the eggs, or " grains " as they are called, 

 of silkworms. Lots of eggs numbering 

 one hundred each were kept in each of these 

 gases for over two months, and then hatched. 

 It was found that the silkworms produced 

 from eggs that had been kept in carbonic 

 acid showed more vivacity and vitality than 

 any of the others. Those from eggs kept in 

 hydrogen were the most backward in devel- 

 opment. Those in oxygen became large and 

 fat, but slow and lazy in their movements ; 

 after the fourth month especially, they would 

 remain in one position for hours at a time. 

 The eggs kept in pure air produced good- 

 sized silkworms, which, however, did not 

 reach a large growth. 



To ventilate a room without draft, make 

 a hole through the wall to the outer air, in a 

 corner of the room just above the skirting. 

 Through the hole put one arm of a tube three 

 inches in diameter, and bent at right angles. 

 The arm of the tube reaching to the outer 

 air should be in length equal to the thick- 

 ness of the wall, and the other arm should 

 be two feet long, standing vertically in the 

 corner of the room; if desired, it can be 

 covered with paper of the same pattern as 

 that on the wall. A tube of the diameter 

 given above is sufficient to ventilate a room 

 of moderate size. 



Near Nienburg, Hanover, waste pyrites 

 from the manufacture of sulphuric acid hav- 

 ing been employed for making roads and 

 paths, it was soon found that grass and corn 

 ceased to grow. Also, a farmer, on mixing 

 well-water with warm milk, observed that 

 the latter curdled. The explanation is, 

 that the waste pyrites contained not only 

 sulphide of iron and earthy constituents 

 but also sulphide of zinc, and that by the 

 influence of the oxygen of the atmosphere, 

 and the presence of water, these sulphides 

 were gradually converted into the corre- 

 sponding sulphates, and the latter, contin- 

 ually extracted by the rain-water, soaked 

 into the soil and contaminated the wells. 



With a view to obtain, if possible, relia- 

 ble data for the localization and diagnosis 

 of cerebral disease, Dr. Lombard made a 

 number of experiments designed to show, 

 first, the normal relative temperature of dif- 

 ferent parts of the surface of the head ; and, 

 second, to show the effect of different men- 

 tal states upon the different portions of the 

 head previously examined. Mental activity, 

 he finds, raises the temperature ; the same 

 effect is produced by simply awakening at- 

 tention. The temperature is very rarely the 

 same in all portions of the head when the 

 brain is in the quiescent state. 



