82 



ON THE MERITS OF IRON AND WOOD FOR HOOFS. 



collecting, but when the boiler is filled again, they should be 

 careful to leave the air taps open, until the water begins to flow 

 out, or, till the boiler is full, to prevent a repetition of the incon- 

 venience. There is also another highly important, arrangement 

 connected with hot water apparatuses, property of the metals, 

 which should be attended to with great care. I mean the al- 

 lowing of a sufficient longitudinal expansion for the pipes on their 

 becoming hot ; as it should be born in mind, that iron pipes 

 when heated to 200 degrees, will expand nearly 2 inches in a 

 length of 100 feet, and as a proof of the necessity of attending 

 to this part, I may relate a circumstance which fell under my ob- 

 servation. A few years ago a nobleman's conservatory in Hamp- 

 shire was heated with hot water, at the expense of between three 

 and four hundred pounds, and the pipes of the boiler were intro- 

 duced through the stone that formed the foot-path, in which holes 

 were cut, just large enough to admit a 4 inch pipe, but not of 

 sufficient diameter to allow^ for the expansion of the metal ; and 

 I well remember, that in consequence of this oversight in four- 

 teen or fifteen different situations where the pipes had to pass 

 through the stone, the joints burst. In each of the SO^feet 

 lengths of pipe, which amounted to about seven or eight lengths 

 altogether, one third of the joints burst, which had only been 

 used three or four times at intervals, it continues to crack to this 

 hour and will do so until they allow room for the expansion of 

 the pipes where they pass through the stone. Having thus given 

 a few brief instructions for the management of hot water appara- 

 tuses, and knowing there exists a great diversity of opinion re- 

 lative to the quantity of water a boiler should contain, and of the 

 dimensions of the water way both 'in pipes and boiler, so as to 

 secure a regular and lasting temperature, I hope it will not be 

 considered presumptuous in me to offer a few observations on 

 that subject, and leave the impartial reader to decide the ques- 

 tion. It is natural that every constructor of hot water apparatus 

 should be prejudiced in favour of his own peculiar plan, the child 

 of his own mind ; here it is that the prescribed dimensions of 

 the conducting pipe s, vary from | an inch to 5 or 6 inches in 

 diameter, according to the different plans of different individuals. 

 I shall merely give my judgment on the proper sizes, without 

 commenting on any peculiar plan. It is my opinion that hot 

 water apparatus, to answer all the desired purposes, should be 

 so constructed as to avoid either objectionable extremes ; since 



