416 Intelligence and Miscellaneous Articles. 



M.D.; Bryan Donkin, Esq.; Very Rev. Dean of Ely, V.P. ; Thomas 

 Galloway, Esq., M.A. ; William Robert Grove, Esq., M.A.; Leo- 

 nard Horner, Esq., V.P. ; Sir J. W. Lubbock, Bart., M. A., V.P. ; 

 John Forbes Royle, M.D. ; William Sharpey, M.D. ; William Henry 

 Smyth, Capt. R.N. ; John Taylor, Esq. ; Charles Wheatstone, Esq. ; 

 Rev. Robert Willis, M.A. ; Lord Wrottesley, V.P. 



—■— 'v^Jl.XIX. Intelligence and Miscellaneous Articles. 



* | NOTE Bl&MR. T. HOPKINS ON HIS PAPER ON THE SEMI-DIUR- 

 1 V Ci) cirUCgfi) NAL FLUCTUATIONS OF THE BAROMETER. 



w To Richard Taylor, Esq., 



s -•/>;!> a &*$>&■> 



IN looking over my paper, inserted in the Philosophical Magazine 

 for March, " On the Causes of the Semi-diurnal Fluctuations 

 of the Barometer," I discovered that a mistake had been made in put- 

 ting down the figures in the Plymouth table, which express the tem- 

 perature at 1 p.m. The mistake arose in this way. In the tables, 

 as inserted in the Report of the British Association for 1839, the 

 temperature for 1 p.m. is entered 45*83. This appeared a typogra- 

 phical error, and in order to correct it a 5 was substituted for the 4, 

 leaving the numbers 55" 83. This temperature of the dry thermo- 

 meter was then compared with that of the wet-bulb thermometer, 

 and the influences of temperature and evaporation as thus exhibited 

 were inferred and remarks were made upon them in the paper. But 

 an examination of other parts of the Plymouth report now shows 

 that the figures 45 in the thermometric column should have been 

 transposed, when the temperature at 1p.m. would have been found 

 only 54*83 instead of 55 '83, making the rise of temperature from 

 10 a.m. to 1 p.m. only 1*99, whilst the force of evaporation is only 

 0*89. The tabular statement of the rise of temperature and the force 

 of evaporation at the two periods would then be from 



c i. in f 5*86 of temperature and 1 , 



5 to 10 < o , o r 4.- / caused a rise, 



1 2* 18 of evaporation J 



10 to 1 I 1 ' 9 * °l tem P era <i ure and \ caused a fall. 

 L 0*89 of evaporation J 



Wishing to be correct in my statements, I have to request that 

 you will insert this letter in the next Number of your valuable pub- 

 lication. 



I am, Sir, 



Your most obedient Servant, 

 Manchester, March 6, 1846. Thomas Hopkins. 



ON SOME NEW COMPOUNDS OF PERCHLORIDE OF TIN. 

 BY M. LEWY. 



The author remarks, that although the perchloride of tin has been 

 the object of numerous researches, the compounds which it forms 



