Thermogenic Apparatus.—Gas from Peat. 261 
gen. It was hence the carbonic acid which caused the sensation of 
heat and the irritation of the eyes. At two other times, in 182 
8 A 
served that the workmen who work long in the solfataras of the Cor- 
dillera, in contact with the carbonic acid, experience an enfeebling of 
the sight, and some of them become blind. 
Dr. Herpin confirmed the fact with regard to the action on the eyes 
action by interposing muslin. When the eyes have an inflammatory 
tendency, it irritates the organ and even vi neighboring parts; the 
heat sometimes produces ins a conges 
Thermogenic Apparatus.—For some ae pee there has been a ma- 
conical r which is reduced to vapor fills the void space 
between the inner walls of the heater and the outer of the conical tube. 
Into the conical tube is passed a cone of wood, covered throughout 
with a braid of hemp rolled sp . The cone of wood is traversed 
by an iron axis, and fills exactly the exterior capacity of the tube, so 
as to rub constantly against its w It is put in motion by a fall of 
water from the t. Martin, so as to make about 400 turns per 
water of the Pig a thermometer placed within the boiler indicates 
at the end of a certain time a temperature of 130°C. he boiler is 
strengthened in ihe ordinary way, with safety stop-cocks, a float, ma- 
nometer, &c. The vapor reaches hardly a pressure of 24 atmospheres. 
A greasing apparatus conveys cainsingtly to the envelop of the cone 
the ¢ oil required to sustain the motion. eee, 
This machine holds 400 litres of water. To be set in action it re- 
machine is at work at the Seren Palace of Paris. : : 
Gas from Peat.—There is much discussion in connection with the 
renewal of the engagements of the city of Paris with the gas compa- 
nies. Attention has thus been called to the gas from peat, which for some 
time has been manufactured at Pari . Leon Foucault has been 
ce manufacture o is more simple than that of coal. 
€ peat, if put into an iron retort, heated to a low red heat, affords 
immediately a “nisl of permanent gases, and vapors which condense 
