122 MOHR AND REDWOOD'S PRACTICAL PHARMACY. 
hot water and steam, with provision for carrying steam or 
noxious vapours, from any process, up the chimney. 
I have arranged this furnace with a view to its being 
economically and easily constructed. The top plate X, and 
the front with doors and return ends Z, should be of cast 
iron, half an inch in thickness. It would be necessary to 
have patterns made in wood from which to make these 
castings, but if it be a consideration to construct it at the 
least possible cost, the front maybe made of brick, thus dis- 
pensing with the outer cast iron case ; and the doors for the 
furnace, ash-pit, and drying closet, may be bought ready 
made, at any ironmongers. The drying closet door is such 
as is commonly used for the oven fixed in kitchen ranges. 
The boiler D is also kept by most ironmongers. The draw- 
ing is made from one of those manufactured by the Carron 
Company of Thames Street, London ; it is three feet six 
inches in length. The pipes for supplying and drawing off 
the water, and also the steam-pipes are attached in the 
usual manner. The supply of water to the boiler may be 
regulated by a cistern with a ball-cock, similar to those 
adopted for kitchen ranges, or by a bailor stone float in the 
boiler itself similar to those used with steam boilers. The 
former of these plans is perhaps the least expensive, and 
most easily effected in country places ; it is, however, sub- 
ject to this objection, that in using the steam, a certain 
amount of pressure is required in the boiler, which will 
force the water into the supply cistern, and sometimes cause 
it to overflow there. This result may be obviated by having 
a stop-cock between the supply cistern and the boiler, so 
that when pressure is required, this communication may be 
cut off. In this case, and indeed under any circumstances, 
it would be desirable to have a glass tube 0, for indicating 
the height of water in the boiler. One end of this tube is 
inserted into the pipe of the tap N, and the other end com. 
municates by a piece of metallic tube with the upper part 
of the boiler. The opening E, in the top of the boiler, may 
have a dashed cover fitting on with a water-joint, as shown 
