METEOROLOGY. 39^ 



with a current, the other manometer will register, e. g., 6.; the pressure 

 here is negative, and due to acceleration of the velocity of the current. 

 {Nature^ xxv, p. 356.) 



Prosser having exhibited a drawing of the anemometer of D'Ons en 

 Brays at the anemometer exhibition of the London Meteorological So- 

 ciety, under the impression that it was the earliest self-registering ane- 

 mometer, also gives in Nature, Vol. XXY, page 505, references to the 

 anemometer invented by Sir Christopher Wren, as described in Birch's 

 History of the Royal Society, published in 1663. (If we combine his 

 references with the description of an anemometer given in Sprat's His- 

 tory of the Royal Society, London, 1667, we must be convinced that to 

 Sir Christopher Wren is due the invention of that form of anemometer 

 that has of late years frequently been styled Wild's tablet anemometer; 

 indeed, to him seems to be due almost wholly the early stimulus given 

 to meteorological observations in England.) Prosser also refers to the 

 famous paper by Edgeworth on the pressure of the wind upon surfaces 

 of different forms, published at page 136, Phil. Trans, for 1783. 



In order to avoid the assumptions that seem necessary in reducing 

 ordinary anemometric observations at sea. Abbe has proposed to estab- 

 lish at various parts of a vessel triple anemometers, recording respect- 

 ively the three vertical and horizontal rectangular components of the 

 compounded motions«of the wind and the instruments. As a first step 

 in this investigation, three anemometers were, in October, 1882, set up 

 at different points on the steamship Ohio, and observations kept up by 

 Mr. Frank Waldo between Baltimore and Hamburg. 



Mr. W. Bailey exhibited to the Physical Society of Loudon on the 

 10th of June a model of the new integrating anemometer. The disk is 

 revolved by means of Robinson's cups. {Nature, xxvi, p. 167.) 



The brothers Brassart, of Rome, philosophical-instrument makers^ 

 have devised a simple inexpensive anemoscope and anemometer, about 

 forty of which are now at work at various Italian stations. {Nature, 

 XXVI, p. 511.) 



MM. Mignan and Ranard have constructed an integrating hygrom- 

 eter for i^recipitating the vapor of "the atmosphere, and analyzing 

 the products, if required. It is composed of an iron tube, filled with 

 liquor ammouise; by gently opening a tap the ammonia is absorbed 

 by water, and the hygrometer is covered with moisture, which is col- 

 lected in a cup arranged for the purpose. During the recent dry weather 

 the amount of precipitation was 3 grams of water in twenty minutes. 

 The weight of liquor ammonite was 34 grams. A peculiarity is that 

 a number of floating particles are precipitated with the humidity of the 

 air. It has been suggested by M. W. de Fonvielle that the hygrometer 

 might be used for analyzing the matter of clouds where the precipita- 

 tion of a few grams will be a question of a very few minutes. {NaturCy 

 xxv, p. 565.) 



Crova describes a new condensation hygrometer. A small tube of 



