4/04: Royal Society, 



April 11. — ^Tiie Rev. Mr. Pritchard, F.R.S., gave an account of 

 the Processes requisite to render Quicksilver tremorless for Astro- 

 nomical Observation. 



The great improvements recently introduced, and especially by 

 the present Astronomer Royal, in the construction and methods of 

 using astronomical instruments, require a far more extended use of 

 reflexion from mercury than heretofore. Unfortunately, however, 

 both the convenience and the accuracy of these methods have been 

 greatly limited and impaired by the tremors to which mercury is 

 liable. Many attempts have been made both in France and in Ger- 

 many to remove or obviate these tremors, but hitherto by no means 

 with perfect success. The Rev. C. Pritchard, of Clapham near 

 London, has proposed a method which appears fully adequate to the 

 requirements of astronomy. It consists in the adoj)tion of a silver- 

 plated or amalgamated copper vessel of a peculiar form, admitting 

 the use of a very thin stratum of mercury without the necessity of 

 an inconvenient amount of shallowness in the vessel itself. Mercury, 

 however, placed in an amalgamated vessel after a short time becomes 

 covered with a singular film of amalgam, which impairs the reflect- 

 ing power of the surface, and if at all agitated, soon entirely destroys 

 it. And this is the case even when the vessel is made of amalga- 

 mated platina. The most important, and by far the most diflUcult 

 part of Mr. Pritchard's experiments, consisted in the invention of a 

 method by which these films can be easily and practically removed. 

 The details, many of which are curious and interesting, would here 

 occupy too much space, but they are fully explained in a memoir 

 recently read to the Royal Astronomical Society of London ; and it 

 may be added, that the process has been adopted at the Royal Obser- 

 vatory at Greenwich, and is now in progress of triaLattbe-Obser^ia^ 

 tories of Paris and Cambridge. ;]> iiiij^rurom sd^ :tx> snoir 



— : bl,91 8«w .Y^ < ROY AX SOCIETY. urf yj b^ ^.pad 



r/v. ^.■.■,..^/ ,„;,,,;,>i[Coi^t^'^^^^^ from p. 381.] 



March 3, 1853. — A paper was read, entitled " On the Meteorology 

 of the English Lake District (Sixth paper, for 1852)." By John F. 

 Miller, Esq., F.R.S. &c. * 



This paper contains records of the meteorology of the Lake district, 

 similar to those of former years which have been communicated by 

 the author. These are given in tables : — Table I. is a Synopsis of 

 the fall of Rain in the Lake district of Cumberland and Westmore- 

 land in the year 1852. Table II. Wet days (the number in each 

 month and the whole year at each station). Table III. The quantity 

 of Rain received by the mountain gauges in the year 1852 (for each 

 month). Table IV. The quantity of Ram for the summer months 

 (May to October). '1 able V. For the winter months (November to 

 April). Table VI. Temperature (max. min. approximate mean) at 

 Seathwaite, Borrowdale, 368 feet above the sea- level (for each month 

 and for the year). Table VII. Temperature at Whitehaven. Table 



