The increase in the consumption of basic slag was remarkable. The 1916 figure was double that of 1913, the whole of the 165,000 tons formerly exported being absorbed. Increased producing facilities and the exploitation of a lower grade waste, as already mentioned, served to increase the consumption for 1917 a further 150,000 tons to 500,000 tons, which represented the maximum capacity of the works specializing in this product. But although the latter could not be extended to meet the still rising demand, owing to the difficulties encountered in connection with the provision of machinery, every effort was made to keep supply astride of demand. Many cement works throughout the country had been compelled to cease operations owing to the stoppage of constructional activity and were lying dormant. As these possessed machinery excellently adapted to the preparation and grinding of the slag they were pressed into service, especially for dealing with the lower-grade waste from the blast-furnaces. In this way provision was made for lifting the output to 600,000 tons or more a year. So far as the superphosphates are concerned the deficiency experienced in this connection has not been so easy of solution. Our resources in the essential material, so far as is known, are somewhat sparse, while a further problem arose in connection with the sulphuric acid, which was in keen request for other purposes. The issue was met by continuing the importation of the crude rock from the northern coast of Africa, and in this manner we contrived to satisfy our needs. But, during this period, the opportunity was taken to ascertain whether or no there did happen to be any suitable rock or other waste which we were neglecting, inasmuch as the moment war ceased immense quantities of sulphuric acid, then being absorbed for the production of munitions and other military requirements, would be released. Investigation was directed once again to the coprolite beds in the Eastern Counties which were formerly worked to yield artificial manures of this character, but which had been abandoned. They were again taken up, and a domestic superphosphate production industry resuscitated upon a limited scale. But whether under normal trading conditions it will prove remunerative to continue this phase of native activity time alone can prove.