But there is no need for us to grow apprehensive. In another chapter I deal with the benzol question, and illustrate how we might increase our supplies of a home-produced fuel to displace imported petrol. In meeting our domestic benzol requirements we can increase our output of sulphate of ammonia at the same time. The ammonia is the substance which so worried gas engineers during the early days of gas-lighting. Then it was an unmitigated curse: to-day it is a blessing. The actual yield of sulphate of ammonia from a ton of first-class gas-distilling coal may be set down at 18 lb. However, seeing that this varies according to the quality of the coal, I will set this figure at 15 lb., which is distinctly conservative. On this basis, if the whole of the coal burned to sheer waste in the private grates of the country, and which may be set down at 100,000,000 tons under normal conditions, were first carbonized, it would be possible to add at least 700,000 tons to our present output of sulphate of ammonia, which would thus be brought up to approximately 1,160,000 tons a year. This would be quite enough to satisfy the needs of all our customers. But, at the present moment, owing to our supineness, the ammonia and the benzol are being allowed to fly up the chimney. Consequently every person who adheres to the consumption of coal instead of coke, in the open grate, just because a blaze is appreciated, is doing his or her bit towards the loss, assuming the value of the fertilizing agent at the modest figure of £10 per ton, of £7,000,000--$35,000,000--per annum. Truly we are paying dearly for the gratification of a whim. Second in popularity among the artificial fertilizers comes basic slag. This is another waste product, being the refuse from our steel-works. It has been allowed to pile up in the vicinity of our blast-furnaces to the detriment and disfigurement of our countryside. But an observant and persevering individual probed these unsightly heaps to discover that they contained a valuable food for plants, and in sufficient quantity to render it remunerative to pulverize the rock-like mass into a fine powder. Forthwith, where phosphatic content was sufficiently favourable, the dumps were taken in hand to be ground up into a flour to be distributed over the soil.