32 ON THE PERCH LOR ATE OF THE OXIDE OF ETHULE. 
I know nothing of this species, but from the specimens sent 
by Dr. Wallich to Sir W. J. Hooker's Herbarium and to my 
own. The specific character which I have drawn up, may 
therefore seem insufficient to distinguish it ; and I might per- 
haps, have considered it only a variety of H. Cambogioides, 
hut for the complete identity of form in the specimens from 
Dr. Wallich ; their prima-facie difference from any of those 
received from Mrs. Walker ; their considerably larger dissi- 
milar leaves, and also their very different geographical posi- 
tion, less unlikely to possess natives of Siam than of Ceylon ? 
Dr. Wallich's plants were obtained in Silhet. 
Companion to the Botanical Magazine. 
ART. V. — ON THE PERCHLORATE OF THE OXIDE OF 
ETHULE OR PERCHLORIC ETHER. By Clark Hare and 
Martin H. Boye. 
The energetic properties of perchloric acid, and its stability, 
compared with the other compounds of chlorine with oxygen, 
led us to the belief that this acid might be combined with the 
substance which performs the part of a base in that class of or- 
ganic salts which are generally designated by the name of 
ethers, and for which Berzelius, in consequence of his theo- 
retical views, has adopted the name of oxide of ethule. For 
this purpose a concentrated solution of perchlorate and sul- 
phovinate of barytes, in equivalent proportions, was subjected 
to distillation. The sulphovinate of barytes may be consid- 
ered as a double sulphate of barytes and the oxide of ethule ; 
and we anticipated that, when heat was applied, a double de- 
composition would take place between the latter and the per- 
chlorate of barytes. So long as the salts remained involution 
no reaction occurred, but as soon as they became solid, in con- 
