Meetings of the Scientific Association of Great Britain. ‘71 
this feeble flame has little heating power, and passes to ordinary 
flame, by a rapid transition, accompanied by a feeble detonation. 
Some metals, as zinc and potassium, shew the same phenomenon, 
but, owing to speedy oxidation, it ceases sooner in them than in or- 
ganic bodies.» 
The application is obvious, in suggesting to manufacturers the 
danger of sudden inflammation, as in candle and soap-making, in 
which vapors are exhaled, during the whole process of manufacture. 
Coal tar and water for fuel—Dr. Daubeny brought forward the 
economical use of coal tar in connexion with water as a fuel.* 
Mr. Low stated that, from long experience he was convinced that 
water was of no service in generating heat with coal tar, and that 
three gallons, or thirty three pounds of coal tar are equal in heating 
effect to forty pounds of coke, made from the Newcastle coal of the 
Hulton seam. 
The conclusions drawn from a somewhat protracted discussion, 
were, 1. That tar is not much superior, as a fuel, to the same weight 
of the best coal. 2. That when mixed with water, it flows more 
easily through tubes, but does not appear to evolve more heat than 
when used alone. 
Sept. 11.—Sulphur in Bar iron.—Mr. West shewed, that the 
best bar iron gives off sulphuretted hydrogen during its solution in 
muriatic acid, and that sulphur being present in most malleable irons, 
injures their properties. 
Amber from Ava.—Sir David Brewster gave a notice of a large 
specimen of amber from Ava, which was intersected by thin layers 
of carbonate of lime. 
Carbonic acid in the atmosphere—Mr. W. H. Watson showed 
that in the town of Bolton, twelve observations in the country, gave 
in 10,000 parts of air, carbonic acid 4.74 for a maximum ; 3.89 for a 
minimum ; mean 4.135; in the town, nineteen observations gave the 
maximum 8.62; minimum 4.19; mean 5.30. 
Sept. 12.—Hot blast.—Dr. Clark stated, that in Mr. Nixon’s 
process for smelting iron by the hot blast, one ton of iron is now 
produced by two tons, fourteen cwt. of coal, instead of eight tons, 
one and a half ewt. formerly required, thus causing a saving of five 
tons, eight cwt. 
* This has been long known in this country; the fact was discovered by Samurt 
Morey, and an account of his process, may be found in the first vol. Am. Jour. of 
Science, 1818 ; and many experiments by him in subsequent volumes, passim. 
