184 THE GARDENER. [April 



boiler gives, in my humble opinion, greater force to the circulation of 

 the water. 



I, like Mr Hammond, would not discuss the merits of the various 

 boilers, each of which is supposed to be the best by its supporters. I 

 have had experience of a few ; and I must say that when properly 

 fixed, kept regularly cleaned, and otherwise judiciously managed, all 

 have worked well. 



I however venture to say, that a boiler that is fitted inside for the 

 regular How of the water in divisions from the lower to the higher 

 parts, so that the water has to traverse the whole of the boiler before 

 getting out by the flow, will have an advantage over those that are 

 not thus divided. R. Inglis. 



In your last month's impression I noticed an article on the above 

 subject, condemning the present system of fitting up hot-water ap- 

 paratuses for heating plant-houses, which contains various statements 

 the accuracy of which I question. Your correspondent, after allud- 

 ing to the difference of opinion regarding the best pattern of boiler 

 for economising fuel, goes on to say " that the circulation of the 

 water in pipes will be as rapid with the bottom of the boiler one foot 

 below the level of the return, as it would be were it several feet 

 deeper : and instead of a continuous ascent of the flow-pipes being 

 necessary it retards circulation." He then gives his reason why water 

 circulates under any condition, and asserts as the basis of his theory 

 that the particles of water are incapable of transmitting heat to each 

 other. I would ask your correspondent, if the particles of water are 

 unable to transmit heat, how does hot water impart its heat to cold 

 w T ater when, if there is an equal weight of each put into a vessel, the 

 temperature will become the mean between the two? Perhaps your 

 correspondent may answer that it is caused by the hot getting so 

 minutely mixed with the cold particles that it equalises the whole, 

 which is true to a certain extent. But if hot water is incapable of 

 conducting heat, how does it come to pass that hot water poured upon 

 ice imparts its heat to it, the ice being then a solid ? It cannot be 

 caused by circulation or the mixing of the particles with that of the 

 ice, and the ice has come in contact with no heated body but the 

 heated particles of water. But the fact is, water transmits heat to 

 water in the same degree as it does to any other substance or body. 

 Again, he says that if particles of water were capable of transmitting 

 heat in the same way as that of solids, it would be impossible through 



