Hood on 'warming Buildings hi) Hot Water. 51 



up, when the Emperor Paul turned the conservatory into a stable 

 for cavah'y horses; and after his death, when it was restoi*ed to 

 its original use, it was heated by German stoves. In France, 

 in the Paris Garden, Bonnemain's plan was given up, because 

 it was found that the pipes did not give out sufficient heat 

 during weather of extraordinary severity. Had the idea oc- 

 curred of increasing the number of the pipes, the mode of 

 heating would probably have been retained; but at that time 

 all France was occupied with political subjects ; and the Revo- 

 lution of 1789 threw Bonnemain and his plans into obscurity, 

 from which neither seem ever to have recovered. Bonnemain 

 was living on a very small pension in Paris in 1829, and, pro- 

 bably, is so still. (See Dr. Ure in Arclu Mag., vol. v. p. 39.) 



" The origin of the invention of employing hot water for diffusing artificial 

 heat," says Mr. Hood, " appears to be hid in considerable obscurity. It is 

 not improbable that, similar to many other discoveries, it has been evolved at 

 various periods from the alembic of Time. It seems, in one instance at 

 least, to have been used in France about sixty years since. After fading from 

 recollection for a space of about forty years, it appears to have been reinvented 

 by the Marquis de Chabannes, and subsequently by Mr. Bacon and Mr. Atkin- 

 son ; and it was the latter who, undoubtedlj', first gave to the apparatus the 

 arrangement under which it is now generally used in its most simple form. 



" Neither the capabilities of this method of warming, nor the various useful 

 purposes to which it is applicable, are at present fully appreciated. There are 

 no buildings, however large, to which it cannot be advantageously adapted, 

 nor any that present insurmountable difficulties in its practical application. It 

 is an invention only yet in its infancy, but which gives promise of a maturity 

 that will confer the greatest advantages, where its employment is the most 

 extensive." (p. 5.) 



Chap. I. Of the Cause of Circulation of the Water, and its 

 Consequences. Here the author shows that Mr. Tredgold's ex- 

 planation of the cause of the circulation of the water (viz. its 

 expansion by heat) is erroneous ; and that the true cause is gra- 

 vitation. It is due to the memory of Mr. Tredgold to state, that 

 it is very doubtful whether the part alluded to in his Treatise on 

 the Steam -Engiiie was written by him. If our memory serves us 

 right, it was published after his death. 



Chap. II. On the Application of the Principles. Chap. iii. 

 Of the proportionate Sizes of various Parts of the Apparatus. 

 Chap. IV. Of the Permanence of Temperature, depending on the 

 Form and Size of the Boiler and Pipes. Chap. v. Of the Size 

 and Construction of Furnaces. Chap. vi. On the Laws of 

 Heat. Chap. VII. Experiments in cooling. Chap. vjii. On the 

 Application of the Laws of Heat to determine the proper Size 

 of an Apparatus for heating any Description of Building. 



Chap. IX. On peculiar Modifications of the Hot-water Appa- 

 ratus. After describing Kewley's siphon principle (p. 127. to 

 1 32.), the author says, " This form of the apparatus answers the 

 intended purpose extremely well, and has been extensively em- 



E 2 



