Heating hy the Circulation of Oil. 207 



having damped off the draught, and thereby cooled the heat of 

 the boiler, the water descended again into it, and flowed 

 copiously. 



" The only explanation I can give you of the cause of this 

 accident is, that the fire-grate was considerably too large, the 

 flue having a great draught ; and the man had made a fire more 

 than three times as large as was necessary. The consequence 

 was, that the great heat thus produced generated steam faster 

 than it was carried off by the tube d, and thus displaced the 

 water from the boiler. This will explain the rising of the 

 water in the vessel a b : and then, I conceive, a small quantity 

 of water became suddenly converted into steam, and produced 

 the explosion which opened the rivets. 



" I am. Sir, yours, &c. 



" W. Carpmael, Engineer. 

 *' 4. Old Square, Liticoln^s Inn, London, 

 Feb. 1833." 



Art. X. Notice of a Method of heating hy the Circulation of hot 

 Oil, instead of hot Water, for tuhich a Patent has been taken out 

 by Mr, TV. D. Holmes; and also of Dr. lire's Method of em- 

 ploying Muriate of Lime as a Medium for communicating Heat. 

 By the Conductor. 



Our readers may have observed, by our advertising sheet, 

 that Mr. Holmes is employed in heating hot-houses and other 

 buildings by hot water ; and that he refers to a number of 

 dwelling-houses, and to the hot-houses of Messrs. Allen and 

 Rogers, in their nursery, Eaton Square, Pimlico, as specimens 

 of his work. We have examined the hot-water pipes on the 

 premises of Messrs. Allen and Rogers, and find that they 

 answer as well as those of Messrs. Walker, and others, who 

 heat on the same plan, viz. that of a close boiler. Mr. 

 Holmes, we find, heats his water in cast-iron tubes, some- 

 what in the manner of Chabannes and Mr. Weeks. 



The object of the present notice is to call the attention of 

 gardeners to the principle of heating by the circulation of 

 fluids which boil at a higher temperature than water; and 

 which, of course, can convey a higher degree of heat to a 

 greater distance than can be done by water in open vessels or 

 tubes. Mr. Holmes proposes to employ oil : an idea which 

 was first, we believe, suggested by the late Mr.Tredgold. 



The mode of circulating oil differs in nothing from that of 

 circulating water ; but oil differs in this, that, at a certain 

 temperature, it becomes carbonised, and in that state is most 



