Intelligence and Miscellaneous Articles. 333 



No. 4. 1*6330 gr. left a residue weighing 0*0025, and gave 5-97945 



= carbon 74*98. 

 No. 5. 0-7510 gr. left a residue weighing 00010, and gave. 2' 7490 

 s= carbon 75*03. 

 " Graphite gave the same numbers ; the residues were pure white 

 silex without a trace of oxide of iron : — 



No. 1. 1*4580 gramme native graphite left a residue weighing 



0*0075, and gave 5-31575 grs. = carbon 75-05 atomic weight. 



No. 2. T5746 gr. graphite left a residue weighing 0*037, and gave 



5*6377 grs. = carbon 75*02. 

 No. 3. 1-6578 gr. residue 0-0084, and gave 6-0385 = carbon 



75*18. 

 No. 4. 1-9040 gr. artificial graphite, residue 0-0105 gr., gave 6-9355 

 grs. i= carbon 75-10. 

 " The mean of these experiments give 75*07 ; we therefore consider 

 75 as the true number indicated by these experiments for the atomic 

 weight of carbon. It is remarkable that this number was fixed upon 

 theoretically by the English chemists, and has now been confirmed 

 by experiments. If we take the number 6*239 for hydrogen, with a 

 very small increase, viz. as 6-250, we arrive at the numbers for oxy- 

 gen, carbon and hydrogen, viz. 16, 12, 2, or 8, 6, 1." 



A paper was read " On Malic Acid, and the Salts of Malic 

 Acid," by R. Hagen, M.D., translated and communicated by T. G. 

 Tilley, Esq. This paper will be found in the present Number, p. 306. 

 A paper was read " On Pyroxylic Spirit," by Andrew Ure, M.D. 

 A paper was read " On the Ferrocyanides," by R. Corbett Camp- 

 bell. 



Both these papers will be inserted, entire, in a future Number 

 of the Philosophical Magazine. 



XLVII. Intelligence and Miscellaneous Articles. 



PREPARATION OF LACTIC ACID AND LACTATES. 



THE following process is recommended by MM. Boutron and E. 

 Fremy, for preparing lactic acid and its salts : — Take about 6 

 pints of milk, and add to it about 8 ounces of sugar of milk dissolved 

 in water. The mixture is to remain in an open vessel exposed to the 

 air, for some days, at a temperature of about 60° Fahr. The liquor 

 has then become very acid, and is to be saturated with bicarbonate 

 of soda. In 24 to 36 hours it again becomes acid, and is to be again 

 saturated, and so on, until all the sugar of milk is converted into 

 lactic acid. When the conversion is reckoned complete, the milk is 

 to be boiled to coagulate the caseum, and it is to be filtered and 

 cautiously evaporated to the consistence of a syrup ; the product of 

 this evaporation is to be treated with alcohol, which dissolves the 

 lactate of soda ; to the alcoholic solution sufficient sulphuric acid is 

 to be added to convert the soda into sulphate, which is precipitated, 

 and the liquor filtered and evaporated yields lactic acid nearly pure ; 

 in order to obtain it perfectly so, it is to be saturated with chalk, and 



