I had of the Lehigh coal was in 1798, when Mr. 
Charles Cist sent a basket of that coal, which was put 
into a carron coal grate, and the fire place inclosed to 
make the current pass through the fire; the heat pro- 
duced was intense. 
As soon as a supply could be had, it was introduced 
at the warehouse, and sent to the factories on Brandy- 
wine. The manner of using is simple, safe and effica- 
cious. It has been used in furnaces (at the factories) 
built on the ground floor. These furnaces are made of 
fire brick enclosed in cylinders of sheet iron; around 
this, and leaving a space of about four inches for an 
air chamber, a circular brick wall is built, and the air 
chamber covered above the top of the furnace. The 
air from without the building is introduced as low un- 
der the air chamber and grate of the furnace as prac- 
ticable, in order to give the greater pressure from the 
external column of air, to promote the combustion 
in the furnace, and to increase the current of warm 
air from the air chambers through the tubes to carry to 
the points required in the factory. 
The conduits for the cold air are large, and also the 
smoke pipes and air tubes, from 7 to 14 inches diam- 
eter. The larger the conduits, and the colder the air 
introduced, the effects are so much the more immedi- 
ate and satisfactory, and it is presumed, that in cases 
where the coal has not been so advantageously used, 
it has arisen from a want of attention to these very 
important circumstances. The smoke pipe, which is 
about 14 inches diameter, contains a tube of warm 
air of about 7 inches diameter; these are carried 
through each floor in copper reservoirs, filled with 
water, which while they remove all risk from fire, the 
evaporation produces a refreshing air in the factory. 
The woollen factory, a building of about 34 by 85 
feet, four stories high, has been rendered comfortable 
with one furnace, except where a stove is required at 
the gig mill. The cotton factory, about 40 by 70 feet, 
three stories high, has never required more than the 
use of one furnace, to render it so warm as required 
in the coldest season. Thus in the one case, supposing 
the building 81 feet long, 31 feet wide and 35 feet 
high, all in the clear within the walls and floors gives 
87.885 cubic feet of air, and the other building 67 feet 
long, 36 1-2 wide and 32 feet high, the stories being 
so much higher within the walls, gives 78.240 cubic 
feet of air rendered comfortable by one furnace and air 
tubes. The expenses I cannot exactly ascertain, because 
until 1822 we could not © tain a supply of your coal 
for both factories, and the sivith shop. For the winter 
season of 1822, 16 tons were used for the factories, and 
the smith shop, and the same quantity in 1823. The 
wood used for kindling, an occasional supply being 
taken from the other stores for weaving shop, dye 
house, &c. &c. cannot be ascertained, nor can we 
exactly state the expenses compared with other fuel, 
but our estimate has been, that 10 to 12 bushels of 
Lehigh coal, of 80]b. weight each, will yield the same 
quantity of caloric or heat as one cord of oak wood of 
128 cubic feet; and one bushel of Lehigh coal will 
perform for us about the same service as one and a 
half bushels of such Liverpool as we have had. 
It might also be stated that a neighbouring factory 
where they used oak wood, the building 4 stories high, 
and not much larger than these already mentioned, 
required about 200 dollars for wood for the season. 
The circumstances already stated will show that the 
Lehigh coal used is by far the safest fuel. There is but 
one fire, and that shut up on the pavement floor; there 
are no sparks, and it is understood that the deposit in 
the pipes and chimnies are incombustible; this however 
may not be the case when the fires are kindled with 
wood, or where wood is used occasionally to continue 
the temperature till the time of shutting up in the eve- 
ning; but in general three fires hold out to serve for 
each day. 
The insurance offices have been so well satisfied 
about its additional safety, that the premiums are 
reduced where it has been in use in the manner stated, 
and which has been introduced from season to season 
into the most extensive factories near the Delaware, 
with some variation according to taste and circum- 
stances. The convenience is also great; instead of 
carrying fuel into the different stories where dust, 
smoke, &c. are disagreeable and often injurious, the 
caloric is carried wherever required without risk, dust, 
smoke or labour. Coal has been used for six years at 
No. 10, S. Third street. The Rhode Island, which is 
more difficult to manage, was used until a supply of 
Lehigh could be obtained. The air is introduced from 
the outside of the room and as much below the grate 
as practicable, by which the combustion is carried 
powerfully on without any consumption of the warm 
air; and by means of the tubes the heated air is carried 
to any point required, within or without the ware- 
house, at a small expense, and without injury from 
smoke or dust: the temperature is regulated by valves 
or registers in the smoke pipes.” 
WILLIAM YOUNG. 
Philada. May 19th, 1824. 
138 B. \LETIN 252: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 
