Superphosphate of Lime. 
151 
the whole of the acid should be directly applied to the bones, and 
that no other substance should be allowed to intercept or abstract 
their mutual affinities. 
A very convenient and cheap vessel for manufacturing the 
mixture is a sugar hogshead, having its holes stopped with 
plaster of Paris. It is very desirable to avoid if possible any 
measuring or weighing of the acid, as it is so very dangerous a 
substance to handle. Many serious accidents occurred to my 
knowledge during the last year, and it is very difficult to impress 
farm servants with a sufficient degree of caution, or even to con- 
vince them that a liquid which appears so colourless will burn 
their skin and clothes. In emptying a carboy of acid even into a 
tub it is difficult to prevent a little slopping about and damaging 
the clothes of the attendants, as well as the basket, &c. which 
contains the carboy. To prevent these unpleasant consequences 
I have adopted the following plan : — The carboy is placed on a 
stage or cask the same height as the sugar-hogshead, into which is 
put the precise quantity of bone-dust we intend mixing with the 
carboy of acid. The water is now added with a watering-pot 
having a rose at the end, so as to disperse it thoroughly, and the 
carboy of acid is then emptied by means of a syphon. This 
syphon is formed of a piece of block-tin pipe, which can be 
bent into any form, about | of an inch in calibre and 4 feet in 
length. A brass cock is soldered to the long end of the syphon, 
on which the rose of a watering-pot may be placed. The syphon 
is now filled with water, and its long end closed with the cock, 
and the small end with the hand or finger. The latter is then 
quickly inserted into the mouth of the carbo}', the cock turned 
on, and the acid will continue to flow till the vessel is nearly 
empty, without any assistance, so that the attendant has no occa- 
sion to expose himself to the injurious and offensive fumes which 
almost immediately begin to escape. He may, however, ap- 
proach the windward side of the tub, and give the mixture a 
little stirring, which should be continued for some little time 
afterwards, so that the mixture may be complete. A convenient 
utensil for this purpose is a fork with two grains, long in the 
grain, bent at some distance from the grains nearly at right angles, 
and fixed in a wooden handle. On the same day a fresh lot of 
bones may be added, and the process repeated until the hogshead 
is nearly full. In two days afterwards the mixture may be 
shovelled into a heap, and either remain till wanted or mixed at 
once with a certain portion of ashes. It should be shovelled over 
several times and ashes added at each time of turning, which will 
thus render the mixture fine and dry enough to pass through an 
ordinarv drill. 
It must be evident that much of the value and economy of the 
