388 SCIENTIFIC RECOED FOR 1882. 



will be constructed on this plan and sent to the Exhibition of Elec- 

 tricity. (Nature, July, 1881, xxiv, p. 225.) 



At the festivities in Paris, 1882, two balloons will ascend connected 

 by telephone wires, and it is hoped if such connection can be maintained 

 to make interesting observations on sound, wind, electricity, &c. 



One of the greatest velocities recorded in aeronautic voyages is that ex- 

 perienced on the trij) of Mr. Joseph Simmons on June 10, who passed 

 from England to France, 170 miles, in If hours, or very nearly 100 miles 

 per hour. (In 1869 Prof. S. A. King traveled from New York into 

 Canada, 400 miles, in 4 hours.) (Nature, xxvi, p. 160.) 



Carlier has made a number of .balloon ascensions in Paris in order to 

 test the possibility of steering a balloon by means of a large oar with a 

 wooden handle, and weighing altogether about 25 pounds ; the surface 

 of the blade of the oar was about 2 square yards, and its efficacy in 

 sculling seems incontestable. {Nature, xxvi, p. 17.) 



One of Jordan's glycerine barometers (see Nature, xxi, p. 377) has 

 been erected at the office of the London Times, and its records are pub- 

 lished daily in that paper. It seems unquestionable that an instrument 

 showing like this on a large scale the minute changes in atmospheric 

 pressure will be very useful for public use in seaports, collieries, &c. 

 {Nature, xxii, p. 614.) 



Professor Kraevitch, of St. Petersburg, exhibited at the annual 

 meeting of the Association of Russian Naturalists, 1879, his new self- 

 recording barometer, which amplifies 140 times the oscillations of a 

 common mercury barometer, and is very sensitive. {Nature, xxii, 

 p. 208.) 



Professors Dufour and Amstein describe a simple registering barom- 

 eter, now in use in the Meteorological Observatory of Lausanne. It 

 depends on displacement of the center of gravity of a glass tube con- 

 taining mercury. The form of the tube may be described as that of an 

 L leading down to a U by a vertical portion. The lower end is open. 

 The tube swings in the plane of its angles on a horizontal axis placed 

 above the center of gravity; with increased barometric pressure it 

 inclines to the right, with decreased pressure to the left; and these 

 movements are recorded by means of a stj^le attached to the U part 

 and applied to a moving strip of paper. By a simple contrivance 

 the pendulum of the clock is made to impart a slight shock every 

 second swing to the tube so as to destroy any adherence of mercury. 

 {Nature, xxv, p. 374.) 



Kraevitch has investigated the limit of rarefaction possible to be 

 obtained by means of the mercury pumj). He maintains that the tube 

 will always remain filled with vapor of mercury and the vapors of the 

 desiccating substances, so that it is impossible to obtain the low press- 

 ure of 0.00004 as maintained by Mr. Orookes. After a sketch of difter- 

 eut air-pumps, he recommends that of Mendelieff. By means of this he 

 says "that the elasticity of the permanent gases may be reduced to 



