PART II. 



DIVISION I. 



APPARATUS REQUIRED FOR PHYTO-CHEMICAL 

 ANALYSES. 



These will be described undei" the following heads : — 



A. Weighing apparatus. 



B. Drying apparatus. 



C Comminuting apparatus. 



D. Extracting apparatus. 



E. Straining apparatus. 



F. Evaporating appai-atus. 



G. Miscellaneous apparatus. 



A.— Weighing Apparatus. 



Three different balances ai'e required for use: — A so-called 

 loeigh-hridge to carry 50 kilograms, and to turn with 10 grams or 

 less, when so loaded ; a common balance, which indicates distinctly 

 1 decigram when carxying 1 kilogram in each pan ; and a chemical 

 balance to carry 50 gi-ams, and to turn, thus loaded, with 1 

 milligram. For better security of dust, fumes, &c., the last- 

 named balance is always to be kept in a glass case. 



The loeights, now in common use amongst analytical chemists, 

 are made according to the French or metrical system, and consist 

 of brass or Gei-man silver. Only the smaller weights, from 1 

 decigram downwards, ai-e made of aluminium. To use platinum 

 for this purpose is inconvenient, on account of the smallness 

 of the pieces, and the risk of losing them. The weights, and 

 especially those under 5 grams, are never touched with the bare 

 fingers, but with pincers made of metal. 



