But the story related of sulphate of ammonia was destined to be repeated in connection with basic slag. It found greater favour in the eyes of the foreign farmer than it did with the native yeoman, although in this instance the circumstance that a mistake was being committed was discovered possibly more promptly. In 1913 our exports of phosphatic refuse from our blast-furnaces were 165,100 tons, for which we received £633,034--$3,165,170. The consumption upon our home lands was about the same, so that the total output was a round 330,000 tons a year. Here again, once the possibilities of the fertilizer were driven home, an increased demand set in. From an attitude of indifference British farmers turned to one of clamour. Fortunately, the first rush was met by placing an embargo upon the export of this article, and, in this way, double the quantity was at once secured for native needs. The demand soon absorbed this extra quantity, and then it became necessary to increase the output of the article. But in this instance the problem was not so readily solved. In the first place the farmer was not disposed to accept this fertilizer when its phosphatic content fell below 25 per cent. But the proportion of phosphate varies widely according to the district whence the ore is forthcoming, as well as the actual smelting process followed. It may range up to as high as 44 per cent. or more; on the other hand it may fall to as low as 12 per cent. or less. Owing to the comparatively limited demand which prevailed for this article before the war, only comparatively few firms essayed the necessary grinding of the rock-like waste from the blast-furnaces. Again it was by no means an easy matter to maintain the slag to the desired phosphate quality. Another disturbing factor was that the smelting of steel, in common with other industrial process, is in a constant state of transition and improvement. This evolution was found to be affecting the slag very adversely, because the tendency was towards lowering of the phosphoric acid content. However, it was discovered that, while the available dumps showing a phosphatic content of 25 per cent. or more were severely limited, there were an appreciable number of slag heaps carrying a lower percentage, ranging down to 17 per cent. of the necessary constituent. These were taken in hand to be passed through the grinding mills. Even this contribution proved insufficient. The demand was met only by working heaps of inferior phosphate quality and adjusting the price according to the percentage of the phosphoric acid present, the figure naturally rising as the proportion improved.