104 
PLAN OF A NEW HOT- WATER BOILER. 
water continued almost boiling the whole time, and of course the temperature of the 
pit was uniform. 
My boiler is made of tin; and the small chamber c is a little projection, added 
to prevent the ascending- and descending currents from interfering with each other, 
which might be the case in so narrow a boiler. I prefer, for an apparatus on so small 
a scale, one pipe to two for the communication between the boiler and heating-pipe, 
as the hottest water will then always remain in the iron pipe^ even if the fire go 
out and the boiler is cool. 
There is one other point in the action of this boiler too important to be omitted : 
by loading the valve at v, until the water rises through the air pipe into the funnel 
H, an oscillating motion is produced between the column of water in the air pipe 
and the weight on the valve ; the result of which is, that the hottest water in the 
boiler, and occasionally some portion of steam, is forced into the iron pipe, where the 
latter is invariably condensed before it can reach the air-pipe, unless the water be too 
low and the fire too strong; in which case it escapes through the funnel, making- 
such a noise as cannot fail to attract the attention of the gardener if any where at 
hand. I need hardly observe the economy of heat is thus as complete as possible ; 
and indeed so completely is all the heat of the fire absorbed, that although my 
chimney is not more than three feet long, I can stop the top with my naked hand 
without inconvenience, at a time when the fire is sufficiently strong to keep the 
water boiling. This, to those who have not tried the experiment, may seem 
almost incredible. I could point out several advantages which this method 
possesses, but they will occur to an intelligent reader. Its superiority, in my view, 
over all other forms of small boilers, is the time which it will continue to burn with- 
out attention, and the economy of fuel, where cinders are the most suitable which 
can be used; 'if applied to a great extent of pipe, of course stronger fuel must be 
employed. 
I might mention its power of heating, but those who are accustomed to such 
apparatuses can calculate more readily than I am able the effect of a four-inch pipe 
at 2] 2°. It raises my little pit 30° or 32° degrees, and of course I am obliged to 
give air all day long. 
P.S. The whole expense of my apparatus was not 4/. 5^. ; if made with copper, 
which it should be to be durable, about 6/. 
ON THE CULTIVATION OF BRUGMANSIA SUAVEOLENS, 
WITH A FEW HINTS ON RAISING HYBRIDS, BY CROSSING B. SUAVEOLENS WITH 
B. SANGUINEA. 
Among the many beautiful plants that now decorate our conservatories and 
flower gardens, perhaps there is not one that has a more splendid appearance (when 
properly grown; than Brugmansia suaveolens, or Datura arhorea of old gardeners ; 
for whether we examine a single flower, or consider the effect of the combined 
