In both cases, the firing of the retorts was moderate, though in the second trial greater care was taken to secure uniformity of heat, and the oil was run in more slowly, so that there was more thorough splitting up of the oil into permanent gas.  The gas obtained in the two trials was of high quality, owing to its containing a large percentage of heavy hydrocarbons, of which there were, respectively, 39.25 and 37.15 per cent., or an average of 38.2 per cent., while the sulphureted hydrogen was nothing, and the carbonic acid a mere trace.  Besides testing the gas on the occasion of the actual trials, he had also examined samples of the gas which he had taken from various cylinders in which the gas had been stored for several months under a pressure of ten atmospheres, and in all cases the gas was found to be practically equal to the quantity mentioned, and hence of a permanent character.

By using Keith’s apparatus the results obtained were generally the same, with the exception that an average of 0.27 per cent. of carbonic acid gas and decided proportions of sulphureted hydrogen were found to be present in the gas.  Dr. Macadam devoted some remarks to the consideration of the question as to how far the gas obtained from the paraffin oil represented the light power of the oil itself, and then he proceeded to say that, taking the crude paraffin oil at 2d. a gallon, and with a specific gravity of 850 (water = 1,000), or 81/2 lb. to the gallon, there were 264 gallons to the ton, at a cost of L2 4s. per ton.  The sperm light from the ton of oil as gas being 3,443 lb., he reckoned that fully 6 lb. of sperm light were obtained from a pennyworth of the crude oil as gas.

Then, taking the blue paraffin oil at 4d. per gallon, and there being 255 gallons to the ton, it was found that the cost of one ton was L4 5s., and as the sperm light of a ton of that oil as gas was 5,150 lb., it was calculated that 5 lb. of sperm light were yielded in the gas from a pennyworth of the blue oil.  The very rich character of the oil gas rendered it unsuitable for consumption at ordinary gas jets, though it burned readily and satisfactorily at small burners not larger than No. 1 jets.

In practical use it would be advisable to reduce the quality by admixture with thin and feeble gas, or to employ the oil gas simply for enriching inferior gases derived from the more common coals.  On the question of dilution, he said that he preferred to use carbonic oxide and hydrogen, and most of the remainder of his paper was devoted to an explanation of the best mode of preparing those gases (water gases).