The Belleville, ever a complicated and delicate mechanism, if its full efficiency is to be secured, was a worse boiler for the experiments than many of the simpler types of to-day would have been. But no water-tube boiler of any type would have stood any chance of success against the opposition. There were some terrible times in the boiler rooms in those days. One or two ships whose chief engineers had been specially trained in France secured marvellous results, usually by ignoring Admiralty improvements and regulations.[20] But for one success there were many early failures. [Illustration: EDGAR. POWERFUL. DIADEM. CRESSY. DRAKE. COUNTY. DEVONSHIRE. PRINCIPAL CRUISERS OF THE WHITE ERA.] The agitation triumphed to the extent of a Committee of Inquiry being appointed. An interim report of this Committee made a scape-goat of the Belleville, to the extent of recommending that no more should be fitted. But the victory of the retrogrades ended there. A species of compromise with public opinion inflamed against the water-tube system was temporarily adopted, and absurd mixed installations of cylindrical and water-tube boilers were fitted to some ships. Four large tube types were selected as substitutes for Bellevilles, the Niclausse, Dürr (a German variant of the Niclausse), the Babcock and Wilcox, and the Yarrow large tube. It may approximately be said that every water-tube boiler is a species of compromise between facility for rapid repair on board ship and complication, and the need of great care in using and working. It is usual to put the Belleville at one end of this scale and the Yarrow (large tube) at the other, this last boiler now requiring little, if any, more care than the old type of cylindrical. In the course of comparatively short experiments, both the Niclausse and the Dürr were found to possess most of the alleged deficiencies of the Belleville without its advantages; and it was decided to fit all future types of large ships with the Babcock and Yarrow types only. The absurd mixture of cylindrical and water-tube boilers was wisely done away with. Curiously enough, the Belleville boiler, once the agitation had ceased, also ceased to be troublesome. This was no doubt due to the increased experience which had been gained in the interim.