aD Cocoa. 
the phosphate of lime and earthy salts by being superficially. 
destroyed, leaves a partially renewed surface of the char- 
coal for ozonic action. The carbon, however, is left in ex- 
cess. In reburning, the foreign matter is charred, and part 
of the carbon of it, together with that of the charcoal, is 
volatilized. A new surface is here again exposed, but the 
phosphates and earthy salts are in excess, and the residual 
charcoal from the organic matter is introduced as a foreign 
element on the surface of the renewed charcoal; in 
course of time the excesses of these extraneously intro- 
duced substances determine the cessation of the normal 
virtue of the charcoal. Much waste and a great amount 
of labour is expended in these fruitless restorations of old 
charcoal and freeing it from impurities. 
By certain of the experiments herein enumerated, animal 
charcoal has been shown by constant use to become im- 
proved. After a continued action on soluble organic matter 
for years the ozonizing power has been stated to have been 
increased. How great, then, the fallacy of submitting such 
to renewal, if, by that process, the standard of its ozonizing 
capacity be reduced to its original condition, or still worse, 
lessened, as above shown. 
The defect of used charcoal has been sought for in the 
wrong direction. If the impurity consists of calcinable 
matter, such as suspended clayey substance, chalk, &c., 
burning is ineffective; if, on the other hand, from organic 
substance, other chemical means for its extraction 
should have been resorted to, and thus the acquired impu- 
rity abstracted, leaving the charcoal improved by the pro- 
cess of its action, and literally imperishable. 
COCOA (THROBRONIA CACAC Fe 
BY JOHN R. JACKSON, 
Curator of the Museum, Royal Gardens, Kew. 
MONG “household words” none are more familiar 
than tea and coffee. The infusions obtained from 
these two plants are not looked upon as a luxury, but asa 
necessary article to the households of all classes alike. As 
a refreshing beverage tea always has held a high position, 
