Professor Dcebereiner's recent Discovery , to Eudiomeiry. 1 IS 
lower than is required by an explosive mixture of oxygen and 
hydrogen gases, a fact with which the preceding experiment en- 
tirely corresponds. 
Mixtures of carbonic oxide, hydrogen, and oxygen, were 
made in different proportions, and brought in contact with pla- 
tinum at various temperatures. The results of these experi- 
ments, however, are so nearly analogous to those already rela- 
ted, that I need not give them in detail Small quantities of 
hydrogen are not rendered obvious by the platinum ; and the 
whole of an explosive mixture is not consumed, unless the hy- 
drogen bear a large proportion to the carbonic oxide, and the 
ball be heated. 
It appears from these experiments, that platinum can give us 
no aid in separating these different gases from one another. 
They shew, however, one very singular fact, namely, that great 
as the power of platinum is in effecting the combination of oxy- 
gen and hydrogen, the presence of certain gases has a very ex- 
traordinary influence, in diminishing that power. This obser- 
vation has naturally led me to inquire into the causes which in- 
fluence the action of platinum; — - an inquiry intimately connect- 
ed with the direct object of this paper, but which I have under- 
taken, not only on that account, but likewise with the design of 
drawing a parallel between platinum and electricity, relative to 
their action on explosive mixtures. 
(To be concluded in next Number*.) 
Art. IX. — Notice of the Colossal Ray or Skate ; with an Ac- 
count of the Capt ure of one , at Port-Royal , Jamaica , where 
it is known under the name of Sea-Devil; By A. Lamont* 
Esq. Lieutenant 91 st Regiment. 
O 
Several of the species of the genus Raia are remarkable, on 
account of their vast size and strength. They occur principal- 
ly in the Tropical Seas, one species only being known as an in- 
habitant of the European Seas, viz. the Ray of Fabroni, a na- 
* We regret that want of room obliges us to delay, until next Number, the se< 
cond part of this interesting Memoir of Dr Turner. 
VOL. XI. NO. 21, JULY 1824. t/ 
H 
