SCIENTIFIC SUMMARY. 
now growing in the Neilgherry Hills and in other parts of India about 
130,000 cinchona plants of the most valuable species, the result of the 
labour bestowed upon the subject. 
The greatness of the work will at once be appreciated if it is remembered 
that the cinchona plant had not yet been cultivated, that its conditions of 
growth were unknown, that it is found in forests scarcely ever visited by 
Europeans, and that great care was required in the selection of the species. 
Mr. Markham, in the prosecution of this undertaking, pointed fout the 
distinction between mere transplantation and that true cultivation which 
consists in placing the plant in circumstances favourable to its develop- 
ment, and removing hurtful influences. 
The importance of the cultivation of this plant cannot be overlooked 
when the immense medicinal value of quinine, and its present scarcity and 
high price, are considered. Already, specimens of the bark from these 
cultivated cinchonas have been analyzed by Messrs. Howard & Sons, who 
report that they contain as good a per-centage of quinine as the cinchonas 
from which they have hitherto been in the habit of extracting that 
alkaloid. 
Mr. Lewis Thompson, M.R.C.S., has been making some experiments on 
nickel with respect to its preparation in a state of purity. He considers that 
the large quantity of arsenic employed in the manufacture of nickel, and 
which is very prejudicial to health, is quite unnecessary; for by first 
roasting the ore, and then heating it with half its weight of chalk, he 
succeeded in obtaining a rough metal containing 88 per cent, of pure 
nickel, the rest being cobalt and iron, with a little sulphur, but no arsenic; 
this metal being decidedly moi'e pure than the ordinary commercial nickel. 
He proposes, as a method for the analytical separation of nickel and 
cobalt from other metals, the addition to the warm solution of the mixed 
snlphates of nickel, cobalt, manganese, iron, copper, &c., of as much 
sulphate of ammonia as the liquid will dissolve, and to set the solution 
aside to cool, when almost every particle of nickel and cobalt will separate 
as double sulphates of nickel and of cobalt with sulphate of ammonia. 
The new metal thallium has attracted considerable notice for some time 
past. From a lecture given by its discoverer, Mr. Crookes, at the Royal 
Institution, we gather the following particulars concerning this metal 
The property by which its discovery was effected was that of giving a 
single brilliant green line when examined by means of the spectroscope. 
Mr. Crookes was engaged in examining the residue from a manufactory at 
Tilkerode, in the Hartz, for the purpose of extracting the selenium from it. 
This was effected in the ordinary way, and the crude selenium was 
distilled. A considerable residuum was left behind in this operation, in 
which he suspected the presence of tellurium. Some time afterwards, 
happening to require some tellurium, he examined this residue more 
minutely, but without getting definite results; the chemical tests appearing 
to give contradictory evidence. Recourse was then had to spectrum 
analysis, when a remarkable green line was observed to cross the field of 
view. This convinced him that a hitherto unrecognized element was 
present, and he set himself to the task of isolating it. At first he inclined to 
the belief that he had a metalloid, or semi-metal, to deal with; but having 
