A man of serious and philosophical mind, an intimate friend of Professor Robison, the physicist, and acquainted with the famous Dr. Black of Edinburgh, then in the thick of his researches on the phenomena of latent heat, Watt often discussed with these two scientists the possibility of improving the steam engine; which apparatus was still only employed for the purpose of pumping water, and which was so clumsy and so wasteful of fuel as to be comparatively little used. To this end he was induced to try some experiments on the production and condensation of steam. The results of these, and a knowledge of the newly discovered phenomenon of latent heat,[78] convinced him that the existing cycle of operations in the engine was fundamentally inefficient, and that improvement was to be sought in the engine itself rather than in the boiler, which was the element which was receiving most attention from contemporary investigators. In particular, he clearly discerned the thermal inefficiency of the Newcomen engine: the waste of heat involved in alternately heating and cooling the large metal cylinder, which absorbed such immense quantities of fuel. Watt’s first idea was, to lag the cylinder in wood so as to prevent all outward radiation. But the result of a trial of a lagged cylinder was disappointing. A gain was certainly obtained in that the steam, when admitted to the cylinder, did not require to raise by partial condensation the temperature of the walls; it exerted its expansive force at once and the piston rose. But on the other hand much greater difficulty was experienced in condensing it when a vacuum was required, for the down stroke. Moreover it was observed that an increase in the amount of injection water only made matters worse. Watt was faced with a dilemma, and he overcame it by a series of studies in the properties of steam which constitute, perhaps, the highest achievement of this workman-philosopher.