HOT WATER APPARATUS. 



23 



was not till a year or two afterwards, that he applied himself to the 

 system of heating rooms, and afterwards hot houses, by means of hot 

 water. That the Marquis, in theory, understood the principle of chculat- 

 ing hot water in tubes, the following quotation from his treatise will 

 clearly shew. " The most perfect definition I can give of the circulation 

 of hot water," he says, " is by comparing the boiler to the human heart, 

 and the effect of caloric upon liquids, to the circulation of blood in our 

 veins. The fire is the power which gives motion to the water, as the 

 admission of oxygen into our lungs causes the circulation of our blood. 

 A pipe is placed at the top, which may have any length or winding, but 

 must finally return to the bottom of the boiler. The caloric which passes 

 into the Mquid, rises to the upper pipe and communicates itself to the 

 liquid in it, which loses that heat as it flows through the pores of the 

 metal, or a reservoir which may be placed in its passage for the purpose 

 of extracting it, becomes gradually cooler, and in that state pressing on 

 the rarified pipe which issues from the top of the boiler, re-enters at the 

 bottom in proportion to what goes out above, thus causing a continual 

 circulation, and the liquid coming in contact with the fire at a colder tem- 

 perature, (and besides with friction), extracts a still greater portion of 

 caloric." Whether he was the inventor of the plan he lays down, however, 

 does not so clearly appear. Our opinion is, that he had no share in 

 the invention, but only acted upon the suggestions thrown out by Bonne- 

 main and others ; for we find by the following passage translated from 

 Encyclopedie Metliodique, that Bosc vdtnessed some experiments in 1816, 

 or before that period. I witnessed," he says, some trials made in the 

 gardens of the Museum, of heating the hot houses by means of copper 

 pipes filled with hot water incessantly renewed. But that plan was given 

 up, because the heat was found, in all weathers, too equal in degree, and 

 too weak during frosty weather." So it would appear, that in France at 

 least, the theory had been for some time known, and it is not improbable 

 that Chabannes, who was httle better than an adventm-er, took the credit 

 of all he had learned in France to himself. 



It also appears, that however he might understand the theory, in its ap- 

 plication he was not so successful ; for with all the advantages attending 

 so important a discovery, and the great pains he took to make his theoiy 

 known to the public, it remained almost unknown until about the year 

 1822, when it was brought most completely into practical operation by 

 Wilham Atkinson, Esq., in his hot houses at Grove End, Paddington, and 

 afterwards in several gardens in various parts of England, under his imme- 

 diate inspection. Mr. Atkinson's original apparatus consisted in connecting 



