NATURAL PHILOSOPHY. 127 



that gases pass with ease. Iiideecl, it ma}'^ he considered as con- 

 clusively proved that cast iron at a red lieat is permeable to car- 

 bonic oxide and certain other gases, even when devoid of any dis- 

 cernible fissures or pores, and when quite impervious to common 

 air. This fact was first made known by the French chemists, De- 

 ville and Troost, in a communication to the Academy of Sciences 

 toward the close of 18G3. In April, 18G5, Dr. Garret, the Surgeon- 

 in-Chief of the Hospital of Cliambery in Savo}', presented to tlie 

 Academy, through M. Velpeau, a paper describing a very pecu- 

 liar epidemic, which had made its appearance on the introduction 

 in that neighborhood of cast-iron stoves in place of the old stoves 

 of tile or porcelain, and announcing the belief that this makxdy 

 was caused by carbonic oxide escaping into the air. This memoir 

 was read without calling forth any suggestion of its important 

 bearing upon the previous experiments of Deville and Troost. 



The Swiss surgeon continued his investigations, gathering fresh 

 proofs of the truth of his previous induction, and toward the close 

 of 1867 addressed a memoir to the Minister of Agriculture and 

 Public Works, in which he distinctly afiirmed the conclusion that 

 the cast-iron stoves allow carbonic oxide to pass out into the air 

 through their walls. 



The attention of the Academy was thus recalled to the subject, 

 and Deville and Troost were invited by General Morin, the distin- 

 guished physicist and engineer, to make the proper test-experi- 

 ments, with a stove of the corps de garde, which he placed at 

 their disposal. These chemists did their work thoroughly ; Deville 

 added similar experiments with the stoves of his lecture-room at 

 the Sorbonne, and the result of all these trials, communicated to 

 the Academy on the 13th of January last, was a confirmation of Dr. 

 Garret's views in regard to the passage of the gases through iron, 

 and thus, for the first time, the attention of scientific men was em- 

 phatically called to the sanitary bearing of facts already known to 

 them, but of which they had overlooked the application. 



Without admitting the conclusion of Dr. Garret as to the pro- 

 duction of the epidemic observed by the escape of these gases, 

 there is no doubt that hydrogen, carbonic acid, and carbonic oxide 

 do actually pass through the walls of a cast-iron stove, at a dull as 

 well as a^ a bright red heat. The fact is worth knowing, for such 

 stoves are often used, and most frequently in ill-ventilated apart- 

 ments. The amount of gases which pass is certainly not large, 

 but carbonic oxide is an exceedingly poisonous agent, and most 

 of the discomfort experienced in rooms heated by these stoves is no 

 doubt attributable to that gas. The subject deserves the attention 

 of manufacturers, who might devise a tile or clay-lined stove that 

 would diminish this inconvenience, and at the same time econo- 

 mize fuel. 



There is also no doubt of the actual leakage of noxious gases 

 through the joints and cracks of stoves, and it is well known that 

 carbonic oxide will transude through a crack which will not allow 

 common air to pass. 



Experiments show that hydrogen will pass through cast iron at 

 the ordinary temperature. M. Cailletet took an iron flask with a 



