S40 



USEEUL PRODUCTS FROM COALi 



covering up in part, or wholly, the fire-place A with a 

 brick. E is a square iron plate with a circular hole in the 

 centre^ built on the top of the furnace. The cast iron 

 basin of the retort G is made to the size of the hole in the 

 plate: the most convenient size of the basin of the retort I 

 find is about five or six gallons, in the shape of a deep pot, 

 with a 'flanch or rim 11 round the edge of it; this pot or 

 basin of the retort is put into the iron plate E, and the 

 flanch of the retort then rests on the plate E. I is the upper 

 part of the retort without a bottom, made to rest and fit 

 on the flanch of the cast iron basin G. K is the receiver, 

 larger in the mouth than the nose of the retort. 



Processor ex- To begin the work, I fill, nearly, the iron basin of tke. 



tracing the retort G with coal.tar. I then put on the upper part of 

 the retort I, and make it air-tight with a little sand thrown 

 round it at the flanch H; the receiver K is put into its 

 place, and a slow fire is put in at A, under the retort; the 

 tar soon begins to boil slowly, or rather simmer. As soon 

 as this begins, there rises from the tar a thick whitish va- 

 pour, which fills the glass retort; part becomes condensed, 

 and falls in drops from the sides of the retort into the tar 

 again, while the purer spirit rises into the neck, is con* 

 densed, and keeps dripping down the neck into the receiver; 

 this is the spirit of (he tar, and with this spirit that first 

 arises from the tar was the waiter japanned which I sent 

 you. The reason I chose to have the receiver wider at the 

 mouth considerably than the nose of the retort is, that 

 (here is a strong and very volatile oily ammonia, that does 

 not soon condense, but gets out of tlie receiver into the 

 air the instant it leaves the retort, and though but in a very 

 small quantity, so small that it is hardly possible to catch 

 it ; yet will it impregnate the air for a great distance round, 

 with jts very penetrating smell, while the spirit keeps 

 dropping into the receiver pure and separate from the am- 

 monia. The spirit is very volatile, quite as much so, if 

 not more, than the spirit of turpentine, and soon eva- 

 porates if exposed (o the air, which is a proof of its dry. 

 ing nature ; indeed when used as a substitute for turpentine, 



, it dries in the stove quite as soon or sooner, and lakes 



equally as beautiful a polish. I sent you three specimens, 



No. 1. 



