118 On the Tides. 
by a professional gentleman who had previously tried it in Walls 
End and Hebburn collieries; and its merits appear to be still 
greater than those of Mr. Stephenson’s. The lamp being sus-— 
pended in a vessel of glass open at the top, and the carburetted 
hydrogen admitted from below, the bright flaine of the wick 
nearly disappeared, but the cylinder of wire-gauze was filled 
with a feeble but steady greenish light. On a greater volume 
of inflammable air being thrown in, the flame gradually died out. 
Results more satisfactory could not be expected nor wished for, 
particularly when we were assured that these accorded with 
numerous trials made in the most hazardous drifts of our coal- 
mines, 
Notwithstanding all that has been lately said in some of the 
periodical publications, respecting the obstinacy of the viewers 
employed here, and the stupidity of their under agents and pit- 
men, you may depend upon it that these safe-lamps are hailed 
by this class of people as a most fortunate discovery, which will 
soon be adopted by them in every mine infected with fire-damp. 
And could a mode be struck out, of preventing inflammation tak- 
ing place by means of the furnace placed at the bottom of the up- 
cast shaft to accelerate the circulation of air through the work- 
ings, little would be wanting to render the occupation of the 
collier as safe at least as that of the persons employed in lead 
and copper mines. 
Your most obedient servant, 
Newcastle-upon-Tyne, Feb. 16, 1816. N. 
XXVI. On the Tides. By M. Laprace*. 
[Read to the first Class of the Institute the 10th of July 182574) 
Tus phenomenon particularly merits the attention of ob- 
servers, both because it is the nearest and most perceptible 
effect of the action of the heavenly bodies, and because the nu- 
merous varieties it presents are well calculated to verify the law 
of universal gravitation. At the request of the Academy of 
Sciences a course of observations were made at the beginning of 
the last century in the port of Brest, which were continued du- 
ring six successive years, and of which the greater part have 
been published by Lalande in the fourth volume of his As¢ronomie. 
The situation of the port is very favourable for observations of 
this kind. It communicates with the sea by meaiis ys a caual, 
* From the Connoissance des Tems for 1818. 
+ For this translation we are indebted to T. S. Evans, jun. of the Col- 
lege schoul, Gloucester. 
terminating 
