ill UYigbis and Medfures. 



fkilful mineralogifts in Cornwall ; and that we have no good 

 fra&ical work in the Englifh language to enable them to ap- 

 ply to farther ufc, what little knowledge they have acquired 

 from working the rich tin and copper mines in that county. 

 Kirwan's Mineralogy is an able fcientific claffification and 

 brief analyfis of the fubjects of which he treats ; but we 

 want fome popular works like thofe of Profefibr Klaproth. 

 For want of proper books of this kind in the Englifh lan- 

 guage, there is reafon to believe that many valuable mineral 

 produces are every day 'loft in Cornwall ; for every fubftance 

 that appears not to pofTefs the characleriitics of the tin or 

 copper, of which they are in fearch, is thrown away among 

 the rubbifh. This was the cafe with the cobalt vein, when 

 a gentleman of more knowledge than the proprietors hap- 

 pened to obferve it. 



WEIGHTS AND MEASURES. 



IN the month of March laft, Citizen Aubry prcfentcd to 

 the Council of Five Hundred a work containing the propor- 

 tions between all the meafures poffible, and a fimple method 

 to difcover thefe proportions. This work is confidered in 

 France as a certain ltep towards an univerfal flandard fa 

 much desired. 



Sir George Evelyn Shuckburgh has lately laid before the 

 Royal Society the remit of many years application and fiudy, 

 upon the fubject of a univerfal fbndard for weights and 

 meafures. He proceeds upon the principles of the late in- 

 genious Mr. Whitehurft, and ufes the identical inftruments 

 he employed. The mean meafure is derived from the dif- 

 ference in length of two pendulums performing a different 

 number of vibrations in a minute. 



