118 
THE DICTIONARY OF GARDENING, 5 
Heating—continued. 
one end, or eyen inside a house, as no bricks are required 
for setting, and the smoke may be conducted from the flue 
to the outside by a circular pipe or chimney. The exterior 
. view of these independent boilers presents a neat appear- 
ance; but it is not advisable to place them inside the 
Fig. 177. UPRIGHT CYLINDER BOILER. VERTICAL SECTION. 
a, Flow Pipe; b, Return Pipe; c, Fire Door; d, Ash-box Door, 
with Ventilator; e, Smoke Flue. 
plant house if it can be avoided, on account of their 
drying effect on the air. Independent cylinder boilers 
are made both with and without an extended top for 
adding fresh fuel. 
Small greenhouses are occasionally heated with boilers 
warmed by gas instead of ordinary fuel. This method is 
rather expensive to keep sufficient water in circulation 
for raising or maintaining a medium temperature in a 
large glass house. It is, however, a convenient mode of 
excluding frost from small structures in places where a 
Fig. 178. WRIGHT AND Co.’s Gas BOILER. 
@, Boiler, consisting of Heating Coil, inclosed in a case: b, Con- 
nection of Burners with Gas-pipe ; e, Flow Pipe a —— Pipe. 
plentiful supply of gas can be obtained. It has an ad- 
vantage for those who do not require much heat, and 
Heating—continued. 
who are unable to attend to fires. When once started 
at the proper rate, the water will continue. to warm and 
circulate so long as the gas keeps burning. A little 
additional water is necessary in the supply cistern occa- 
sionally. Gas boilers, of which Messrs. Wright and Co.’s 
is a good arrangement (see Fig. 178), consist of a heating 
coil of pipes arranged above one or more Bunsen burners 
inside an inclosed case, and having a flow pipe attached, 
which branches into another, as shown in the illustration, 
and returns to the lower part of the boiler. With a small 
flue attached, the whole apparatus can stand in the house 
it has to warm, and thus the full amount of heat will 
be utilised. The product of combustion from a Bunsen 
burner is merely a slight vapour, sufficient oxygen being 
incorporated with the gas, so soon as it leaves the pipe, 
to cause its whole consumption by the fire without any 
soot being left. Two stoves heated by gas, and answering 
Px — 
Fig. 179. RITCHIE’S LUX CALOR. 
A, Door, which opens on a Bunsen burner; B, B, Tubes, in which 
the products of combustion are condensed (with the exception of 
the carbonic acid) into fluid form, 
without flues, are Ritchie’s Lux Calor (see Fig. 179) and 
Clark’s Syphon Condensing Stove, represented in Fig. 180; 
both having Bunsen burners attached. In the Lux Calor, 
the products of combustion, with the exception of carbonic 
acid, are condensed in tubes on either side of the burner. 
Fig. 180. CLARK’s SYPHON CONDENSING STOVE. 
There is little fear of the small amount of carbonic acid 
gas doing injury, as, being heavier than atmospheric air, 
it falls to the lowest point, and is removed by any feeble 
current. This stove is calculated to warm any fairly 
good structure, not too much exposed, with an interior 
capacity not exceeding 1000 cubic feet. The Syphon 
Condensing Stove is constructed on somewhat the same 
lines as the Lux Calor; but, unlike it, the warm air is— 
after parting with the products of combustion—conveyed 
through a tube over the flame and into the space to be 
