548 



February 27; 1845. 



SIR JOHiS WILLIAM LUBBOCK, Ban., V.P. and Treas. in 



the Chair. 



" An Account of Compact Aluminum." By Professor F. Wohler 

 of Gottingen, in a Letter to Thomas Graham, Esq. Communicated 

 by Thomas Graham, Esq., F.R.S. 



The author has lately found, contraiT to the results of his former 

 researches on aluminum made eighteen years ago, that this metal is 

 readily fusible, and that in its reduction from the chloride of alu- 

 minum by means of potassium, it presents itself in the form of fused 

 globules, generally so small that their shape is not distinguishable 

 under the microscope, although occasionally they are met with 

 having a sensible diameter. Lie effects the reduction at once in a 

 clay crucible, the bottom of which he covers with pellets of pure 

 potassium, and places upon these the chloride of ammonium, covering 

 the whole with chloride of potassium in powder. The crucible being 

 then closed up, and heated in a coal fire, the reduction is instantly 

 effected. 



Fused aluminum has the colour and lustre of polished tin ; it con- 

 tinues perfectly white in the air ; it is fully malleable, and the glo- 

 bules may be beaten out into the thinnest plates without cracking 

 at the edges. It is entirely unmagnetic. In other respects the 

 metal in this compact state has the properties which the author for- 

 merly ascribed to it. 



March 6th. 1S4:5. 

 The MARQUIS OF NORTHAMPTON, President, in the Chair. 



" Essays on Hygrometry and Barometry."' By Captain Shortrede, 

 F.R.A.S., First Assistant in the General Trigonometrical Survey of 

 India. Communicated by Lieut.-Col. W. H. Sykes, F.R.S. 



This paper commences with an account of the various investiga- 

 tions of the author on subjects relating to the elasticity of aqueous 

 vapour at different temperatures and under different circumstances. 

 He first discusses the tables given by different experimentalists of 

 the force of vapour at various temperatures, and endeavoui^ to de- 

 duce an analytical formula giving the nearest approximation to the 

 results recorded. He then proceeds to the consideration of what he 

 terms " the moist bulb problem," or the point of maximum depres- 

 sion attained by a thermometer with a moistened bulb exposed to 

 evaporation in air: he deduces formulte which he compares with the 

 results of actual obseiwation, and points out the probable sources of 

 error in the cases in which he finds disagreements between them. 

 In the miscellaneous remarks which form the next section of the 

 paper, the author states his reasons for dissenting altogether from 

 the views taken by Daiton of the constitution of mixed gases, or of 



