468 Scientific Intelligence, (June, 
ArTIcLE IX, 
SCIENTIFIC INTELLIGENCE; AND NOTICES OF SUBJECTS 
CONNECTED WITH SCIENCE, 
I. Fulminating Platinum. 
Mr. Edmond Davy, Professor of Chemistry to the Cork Institu- 
tion, has recently discovered a fulminating compound of platinum, 
which has some curious properties. He is at present engaged in 
examining this substance, and will shortly make known the results 
of his investigation. ‘This peculiar compound explodes at a mode- 
gate heat. This effect is accompanied by a flash of light. The 
substance is completely decomposed, and resolved into metallic 
platinum and gaseous products. When the fulminating platinum is 
put into liquid ammonia it is partially decomposed, and a quantity 
of gas is evolved. In ammoniacal gas, this substance becomes 
ignited. When it is praia with alcohol a slight crackling noise 
is produced, ‘The substance scintillates, and burns with a red fame. 
Hl. Demonstration that no Part of a Circle is a straight Line. 
A Correspondent, who subscribes himself A Constant Reader, 
has sent me the following demonstration that no part of a circle is 
a straight line :— 
In the arc A B of a circle take a small part, A C, which suppose 
to be astraight line. But if AC is a straight 
line, C B, which is equal to it, must be a straight 
line. For the same reason xm, which includes A/” Cn B 
the point in which A C and CB are joined, is : 
also a straight line; and therefore the whole are t i 
A B isa straight line, which is evidently absurd. j 
Therefore no part of a circle is a straight line.— ee iri “Wh 
Q. E. D. 5 
Whether any part of a circle is, or is not, a straight line, is a 
point of difference between some of our most celebrated mathema- 
ticians. On the assumption that a circle is composed of a number 
of small straight lines, Hutton, Leslie, and several other great 
geometers, have built some very important theorems. On the con- 
trary, an ingenious writer in the Quarterly Review for 1810, with 
several others, declaim strongly against the principle. Simpsoa 
and Legendre have likewise discountenanced it. ‘The subject is, 
therefore, of considerable importance ; and the above demonstra- 
tion appears to me satisfactory. U. 
WI. Iron Tube Picrutistlrs: 
ca (To Dr, Thomson.) 
Seing in your Annals of Philosophy that Professor Playfair claims 
the invention of making barometers with an iron tabe and a float, 
’ 
