SOME REMARKS ON HEATIXG. 297 



Mr. Hood's method of setting the arch boiler cannot fail to 

 answer when properly carried out, as I have amply proved. It 

 appears to me, however, that for large houses a greater increase 

 of the piers of the arch would be an improvement, as thereby 

 attbrding more room for fuel. Beyond this, as far as my own ex- 

 perience goes, it seems to be the best source of warming yet de- 

 vised, combining, as it unquestionably does, both efficiency and 

 economy. 



The cause of the motion in hot water, when conducted in pipes 

 through buildings at a lower temperature, has long since been 

 explained. Instead, therefore, of treating this as a theoretical 

 question, I shall deduce from experience a few practical rules for 

 the guidance of those who are less acquainted with the subject 

 than myself. 



In setting the boiler it should always be placed so that no dip 

 in the pipes which may be required in passing doorways or other 

 unavoidable obstructions to their level run, shall be lower than 

 its upper surfice. Any deviation from this rule will naost 

 assuredly affect its proper action, less or more. Nor does it 

 appear that this rule need be deviated from under any circum- 

 stance where hot water is applied to hothouses, if proper pre- 

 cautions are taken. It will only be uecessary to excavate a little 

 lower, for it is always better to err on the safe side. No obstruc- 

 tion or objection can possibly arise to this unless the water is near 

 the surface, and this objection can only be sustained in old 

 buildings. In all new erections care should in the first instance 

 be taken to keep the building sufficiently above ground to admit 

 of any arrangement for heating. This even may be got over bv 

 forming a basin similar to a water tank — circular — with the 

 bottom concave to resist pressure. The arrangement in the in- 

 terior of the building to receive the pipes will of course vary in 

 different structures. This, however, should be so contrived as to 

 admit of a proper distribution of the heat, whether the air only is 

 to be warmed, or the bed for plunging pots. 



When the pipes rise from the boiler into the house, they should 

 then be conducted horizontallij . No deviation from this rule has 

 yet been found of the least utility. They may, notwithstanding, 

 be carried upon different levels, the boiler being a close one. 



It will be necessary to make provision for the escape of air 

 that may accumulate in the pipes, Mdiich would, if no outlet was 

 provided, obstruct the circulation of the water. This is very 

 easily effected by drilling a small hole in one or two of the upper 

 pipes, sufficient to admit ordinary gas tubing, which can be 

 directed up any angle of the building, two or three feet above 

 the highest pipe. In all cases of an ordinary kind this will be 

 found to answer, provided the pipes are accurately laid down, and 



VOL. VI. Y 



