ASTRONOMY. 27 



published in the Proceedings of the American Academy a 

 note on a similar phenomenon, under the caption " The 

 Moon's Zodiacal Light." In the Paris Jlemoirs, 1771, p. 434, 

 Messier describes a similar phenomenon, which lias never 

 yet been explained, and gives a wood -cut of its appear- 

 ance. 



TIME. 



One of the few ways in which astronomy can make itself 

 practically valuable to the community at large is in the dis- 

 semination of standard time to navigators and to men of 

 business. The following notes refer to what has been done 

 in this direction during 1877. 



The recent invention of Barraud and Lund, of London, 

 for controlling a clock by automatic or other signals is de- 

 scribed in an advertisement in the Telegrapliic Journal for 

 May, 1877. It has the capital advantage over the Bain 

 system that the clock may run either fast or slow without 

 aifectins; the control. It suffices to control a clock whose 

 rate is 2 minutes daily. It appears to be a suitable de- 

 vice for the regulation of the clocks of manufactories, rail- 

 ways, churches, etc., where a control to the nearest minute 

 is all that is required, and where economy is necessary. In 

 this connection it may be noted that the Paris Observatory 

 now controls the clocks of the Conservatoire, St. Sulpice, and 

 the Luxembourg, and the system is to be extended to the 

 clocks of the various cab-stands, which will be a very prac- 

 tical and valuable step. 



The public clocks of Vienna are controlled by a pneu- 

 matic-motor clock which is said to have been very satisfac- 

 tory. 



The Trinity House of England is adopting gun-cotton as 

 a means for fog-signals, and it may prove a valuable substi- 

 tute for the time-guns now established in the various ports of 

 the world in cases where the sound only is available for sig- 

 nals. Where the flash can be observed a gun is preferable, 

 or an electric light, as used at Melbourne. 



Redier describes in the Co?nptes JRendus a simple device 

 for correcting the going of clocks for changes in rate due to 

 changes of atmospheric pressure, by means of a small aneroid 

 barometer fastened to the pendulum bob. 



The Naval Observatory of Washington has been for some 



