METEOROLOGY. 395 



1st. It is somewhat larger; 2d. It lias a single set of double ziuc lou- 

 vres ; 3d. It is partly closed at the bottom to cut off radiation. [Nature, 

 XXVI, p. 215.) 



J. T. Brown has communicated to Nature an historical memoir on 

 methods of regulating temperature. Although the methods he enu- 

 merates are especially applicable to small masses in the physical lab- 

 oratories, yet some of them will find extensive application in testing 

 meteorological instruments. {Nature, xxvi, p. 116.) 



Dr. F. D. Brown presents to the Physical Society some notes on ther- 

 mometry, apparently executed with the partial assistance of Professor 

 Guthrre. He describes a convenient method of calibrating ; he finds 

 that a constant zero temiierature is best obtained by a mixture of ice 

 and distilled water ; the attention is called to the changing of zeros in 

 thermometers in heating. (Nature, xxvi, p. 71.) 



G. M. Eldredge communicates to the Franklin Institute at Philadel- 

 l^hia a simple form of thermograph, in which a mercurial thermometer 

 having a tube of large bore, the upper end of which is open, records its 

 fluctuations by pricks upon a sheet of paper by means of an electro- 

 magnet. The entire thermograph differs only in minor details from 

 those which have been introduced by Hough and others. {Nature, xxvi, 

 p. 163.) 



Riviere has observed the cooling of a i)latiuum wire heated by an 

 electric current in dry air within a glass cylinder whose surface is kept 

 at a uniform temperature. He finds the formula of Dulong and Petit 

 to give too rapid cooling, and that of Rosetti to agree somewhat better 

 with the results. {Nature, xxvi, p. 520.) 



Prof. J. M. Crafts communicated a paper to the chemical section of the 

 British Association on the use of the hydrogen thermometer ; this is an 

 air thermometer of constant volume, in which the air is replaced by 

 hydrogen because of the more rapid flow of that gas through a capil- 

 lary tube, and because the bulb of the thermometer could be greatly 

 reduced in volume. He redetermined the boiling point of mercury as 

 357° C., and investigated the boiling i^oiuts of a large number of carbon 

 compounds. {Nature, xxvi, p. 466.) 



J. K. Laughton, at the March meeting of the London Meteorological 

 Society, gave an exhaustive historical sketch of all kinds of anemome- 

 ters known to him. In conclusion, he stated that all forms of anemom- 

 eters give very unsatisfactory results, and what we need is not so 

 much an improved apparatus as a more thorough investigation of the 

 errors and method of action of the best forms of instruments now in 

 use. {Nature, xxv, p. 547.) 



Eev. T. R. Robinson, of Armagh, Ireland, has j>ublished results of 

 further studies on his anemometer. Two similar instruments were 

 established side by side, in one of which the friction was more variable ; 

 their revolutions were recorded chronographically. The equation of an 

 anemometer's motion is Y^ -{- v^ — 2 V vx — (/ -^ a) = 0. 



