322 Scientific Intelligence. [APRIL, 
oxide. An atom of carbonic acid weighs 2751; and an atom of 
peroxide of eopper, 10. Therefore the carbonate of copper in the 
ore amounted to 16°736 grains. Hence the ore is composed of 
Carbonate of copper .... 16°736 .... 69°44 
Biliew Sle! ae Yai ig wows 25°31 
22°S3Gin wie 94:75 
assiiviigie ll qdateides ei ied ital ai iaS 
24°1 100: 
I had not a sufficient supply of the ore to enable me to decide 
whether this 54 per cent. of loss be owing to the presence of water, 
or to an error in my mode of experimenting. J think it not un- 
likely that J may have lost a little of the copper, as I washed it re- 
peatedly with water on a watch-glass, and poured the water off in 
order to get rid of the whole of the zinc solution. Now it is pos- 
sible that a flock or two of the copper might have been carried off 
by the water without my perceiving it. The loss of half a grain of 
copper in that way would account for the greatest part of the loss. 
At the same time I am not aware of having lost any copper, and 
Klaproth found six per cent. of water in a specimen of blue car- 
bonate of copper which he examined. 
X. Death of Guyton de Morveau. 
Some months ago M. Guyton de Morveau died in Paris, at a 
very advanced age. He was probably the oldest chemist in France, 
having been known as a writer for more than 40 years. His Digres- 
sions Academiques, the earliest of his writings with which I am 
acquainted, was published in 1773. Asan experimenter, his merit 
was not very considerable ; but he possessed a much more accurate 
knowledge of the history of the science than most ether French 
writers. Several of the articles in the first volume of the chemical 
part of the Encyclopzedie Methodique, which he wrote, are excel- 
lent, especially the article Acid. It was one of the earliest chemical 
tracts that I read, and I was indebted to it fora great deal of valuable 
information. There isa striking contrast between the volume which 
Morveau wrote of that work, and the various volumes which were 
contributed by Fourcroy, and the superiority is entirely on the side 
of Morveau. His reputation was much higher about the year 1787 
than some years after. I ascribe this, in a great measure, to the 
praises lavished upon him by Mr. Kirwan. I shall take a future 
opportunity of giving a more particular account of the writings of 
this chemist, and of stating the chemical facts for which we are 
indebted to him. 
XI. Indian Arrow Root. 
' This very agreeable starch is obtained from the roots of the 
maranta arundinacea, an American plant, which has been long 
cultivated in the West Indian islands, and which is said to grow wild 
in Jamaica. Tussac, in his Flore des Antilles, published in 1808, 
i 
