228 
THE COTTAGE GARDENER AND COUNTRY GENTLEMAN, January 15, 1861. 
boiler some 2^ inches shallower and inches narrower, and 
place that inside of the other, so as to displace all the water 
except about 2 inches at the bottom and 2 inches round the 
side, and then with such a lessened quantity of water, exposed to 
the same amount of heating power, would not the water be 
sooner set a-galloping more quickly along your flow-pipes ? 
This simple idea or experiment lies at the foundation of all 
our implements in hothouse boilers. Thus knock out the 
bottom of these two boilers, and then fill up the two-inch space 
that separates them at top and bottom, and you have the regular 
cylinder boiler, such as is advertised by Mr. Jones in these 
pages. In these however set, the fire is intended to be in, and 
heat the inside, there being some inches of water all round. In 
jig. 14 we should like the pipes to be 
nearer the top and bottom. This 
would be especially necessary as re¬ 
spects the return-pipe if the boiler is 
to be raised considerably above the 
bars of the grate. If it rests on them 
or nearly so it will not signify so much. 
Forgeneral purposes economy is gained 
when in such boilers the fire is placed 
inside, and thus acts only on the in¬ 
ternal surface; but power would be 
gained if the heat of the fire acted at 
once on the inside and the outside of 
the boiler. 
If we turn such a couple of wash-house boilers topsy-turvy, 
with the wide mouth downwards and a smaller opening cut 
through the top, then we have the conical boilers of many 
makers, all on the same principle as the small one given by Mr. 
Allen at page 134. The chief particular features of that little boiler 
are its being made in pieces easy for transmission, its peculiar 
damper, and the peculiar mode of hanging or swinging the grating. 
Such a boiler would be very useful for a small pit: for a 
moderate-sized house it would need to be fully double the size. 
The fire is generally placed inside these the same as in the 
| cylinder boilers, and to them similar remarks apply. Though 
■ fed from the top, when the boilers are of any size and enough 
fuel is used a furnace-door will be required to stir up the fire 
; and take out clinkers; and in such cases the boiler must stand 
six or eight inches above the grating on firelumps, but they will 
be none the worse on that account. 
Keep your double wash-house boiler topsy-turvy, but instead 
of making a hole in the top make one at each side, the one 
opposite the other, and you have 
the germ of the saddle-back,/?^. 16. 
This is one of the most simple 
and the most useful of boilers 
when well set. The space of from 
two to three inches is generally 
left for water between the inside 
and outside covering. If large, a 
return-pipe is generally fastened 
on each side, joining into one 
farthest from the furnace-door; 
or, if not, a pipe close to the end 
and bottom goes across from side 
to side, generally protected by a 
brick inside. The end there is generally blocked by a Welsh 
i lump, leaving some six or more inches for the smoke and heated 
air, which comes back on each side outside and crosses over 
l the top into the chimney. There are many modifications of 
the saddle-back, almost every maker having some peculiarity. 
Mr. Grey manufactures a very effective one, corrugated inside 
so as to present a large surface to the fire. Messrs. Harwell, of 
Northampton, make what they call waggon boilers, with flat 
tops outside, the inside being rounded as in the common saddle¬ 
back. Of all these we like the simplest best. 
Oflate years we have had many new boilers, each of which 
has had its admirers. Mr. Thompson, of Dalkieth, introduced 
retort boilers. Conceive of a cannon some two feet long, with 
a bore through it of nine inches, and the water contained in a 
small space between that and the outside, with flanges for flow 
and return, and you have before you the amateur’s retort for 
small places. Increase these in length, cast two together, or 
_ three in the shape of a triangle, and you have a doub'e 
or triple retort for doing a great amount of work. 
V ^ They are generally placed lengthwise over the fire, and 
Fifi: ' 17 ' so regulated that the flames pass through or return 
through the retorts before they enter the chimney. Means are 
taken to keep them easily clean. Place them upright, and you 
have single, double, or triple cylinder boilers. 
Monro’s cannon boiler is on the same principle but more 
complicated, and forms the sides of the fireplace for itself. 
Fig. 19. 
Mr. Lobjoit’s boiler we have heard spoken well of, but have 
never seen it at work. A large surface is said to be exposed to 
the fire. 
In a late volume of The Cottage Gahdener I gave a descrip¬ 
tion of the heating by an upright tubular conical boiler at Mr. 
Weeks’, Chelsea. At that time such an amount of work from 
one boiler was unprecedented. Mr. Weeks and his father before 
him had used oblong squares of tubes with the fire inside. The 
Mr. Weeks of the present was the first to use upright tubes on 
the principle of the conical boiler. These tubes at that time 
were in a double row, so that by counting the number of tubes, 
taking their length and circumference, it would at once be ap¬ 
parent, that no other mode could present such a surface to the 
direct action of the fire, placed in the fireplace at the bottom. 
Fig. 20. 
IMPROVED BOILER OF MR; WEEKS. 
There can be no difficulty in setting such boilers. If the brick¬ 
work at a few inches from the pipes could be partly made non¬ 
conducting outwards, by a space of enolosed air, the bricks 
