I have made no attempts to utilize this tar except as fuel. It evaporates nearly twice as much water as its weight of coal, and we have thus to add its evaporative efficiency to that of the gas given above, leading to a total of about 80 per cent. of the evaporative efficiency of the fuel used in the producers. The loss involved in gasifying the fuel to recover the ammonia therefrom amounts thus to 20 per cent. of the fuel used. This means that, where we have now to burn 100 tons of fuel, we shall have to burn 125 tons in the producers in order to obtain ammonia equal to about half the nitrogen contained therein. Our actual yield of ammonia on a large scale amounting on an average to 32 kilos., equal to 70.6 lb. per ton of fuel, 125 tons of fuel will turn out 4 tons of sulphate of ammonia. We thus consume 6.25 tons of fuel for every ton of sulphate obtained, or nearly the same quantity as is used in producing a ton of caustic soda by the Le Blanc process--a product not more than half the value of ammonium sulphate. At present prices in Northwich this fuel represents a value of 35s. If we add to this the extra cost of labor over and above the cost of burning fuel in ordinary fireplaces, the cost of sulphuric acid, bags, etc., we come to a total of 4l. 10s. to 5l. per ton of sulphate of ammonia, which at the present selling price of this article, say 12l. per ton, leaves, after a liberal allowance for wear and tear of plant, an ample margin of profit. With a rise in the price of fuel, this margin, however, rapidly decreases, and the working of the process will, of course, be much more expensive on a small scale, as will also be the cost of the plant, which under all circumstances is very considerable. The great advantages incidental to this process over and above the profit arising from the manufacture of sulphate of ammonia, viz., the absolute impossibility of producing smoke and the great regularity of the heating resulting from the use of gas, are, therefore, as far as I can see for the present, only available for large consumers of cheap fuel. We have tried many experiments to produce hydrochloric acid in the producers, with the hope of thereby increasing the yield of ammonia, as it is well known that ammonium chloride vapor, although it consists of a mixture of ammonia gas and hydrochloric acid gas, is not at all dissociated at temperatures at which the dissociation of ammonia alone has already taken place to a considerable extent.