~ Anthracite Coal of Rhode-Island. = 99 
at present decide.* Neither is it in my power to say 
vticihad the Rhode-fsland coal is generally inferior to the Penn- 
sylvania anthracites, in its power of imparting heat, or wheth- 
er the deficiency found by Mr. Bull, of 28 parts in 99, was 
imputable in whole or in part, to accident in the tion of 
the specimens. It is stated by those conversant site 4 the 
mines, that there is in this respeet, much variety in the coal 
of Rhode-Island. Should it prove on farther trial, that the 
Rhode-Island coal contains less combustible matter, under 
the same weight, the price in the market will of course be 
regulated accordingly. A difference it is very possible there 
may be on this point, in favour of the Pennsylvania coal, but 
I should not think, from any thing that I have myself observ- 
ed, that the average difference in the large way, would prove-as 
pe as the experiments of Mr, Bull would indicate, although 
have entire confidence in the accuracy of those experiments 
in the given case. 
P. S. May 17, 1826 
It is proper to state, that on taking down the tube con- 
necting the anthracite furnace with the chimney, after 
ing the Rhode-Island coal, nearly three weeks, the accumu- 
was dark gray, almost black. It was partially magnetic, suf- 
ficiently so to form a festoon between the poles of a horse shoe 
magnet, but the ashes were perfectly dry, like sand, and ad- 
hered only very slightly to the tube. Should it prove to be 
the fact, that more ashes, arising m impurities, or from un- 
veneers — are re deposited i in the tube, when the Rhode- 
io 
Lt is probable, that in'a vertieal spvery Bete wihies wilt be 
“* June 8, 1926. My friend, Prof. Olmsted, has, at my resaert , repeated, 
with a very pp speci nF inva of the 
R. 1. and Lehigh coal ;—the former be makes 1. 77, the jee 155—corres- 
i in the one case, exracl in the other, nearly, 
Mie Bull gives, for the Rhode-[sland coal, I 438, and fi 
We must impute these differeaces, < variety in speci 
A letter from Mr. Bull, this mosipat: rece 
a myself, contains the cee passage :— 
in our results, as to the sp. gr. of e coals, 
sent fissures, more or less, in almost all instances, and t podaaie’ 
$sland, in which the largest variation 
