[79] “The last step of all,” says Professor Jardine, “was more difficult--the forming of the separate condensing vessel. The great knowledge he had acquired of the mechanical powers enabled him to construct it, but I have often heard him say this was a work of great difficulty, and that he met with many disappointments before he succeeded. I have often made use of this beautiful analysis received from Mr. Watt, in another department in which I have been long engaged, to illustrate and encourage the progress of genius in youth, to show, that once in possession of a habit of attention, under proper direction, it may be carried from one easy step to another, till the mind becomes qualified and invigorated for uniting and concentrating effort--the highest exertion of genius.” Mankind has been more just to Watt than he was to himself. There was no accident in the discovery. It had been the result of close and continuous study; and the idea of the separate condenser was merely the last step of a long journey--a step which could not have been taken unless the road which led to it had been traversed. Dr. Black says, “This capital improvement flashed upon his mind at once, and filled him with rapture;” a statement which, spite of the unimpassioned nature of Watt, we can readily believe. On the morning following his Sunday afternoon’s walk on Glasgow Green, Watt was up betimes making arrangements for a speedy trial of his new plan. He borrowed from a college friend a large brass syringe, an inch and a third in diameter, and ten inches long, of the kind used by anatomists for injecting arteries with wax previous to dissection. The body of the syringe served for a cylinder, the piston-rod passing through a collar of leather in its cover. A pipe connected with the boiler was inserted at both ends for the admission of steam, and at the upper end was another pipe to convey the steam to the condenser. The axis of the stem of the piston was drilled with a hole, fitted with a valve at its lower end, to permit the water produced by the condensed steam on first filling the cylinder to escape. The first condenser made use of was an improvised cistern of tinned plate, provided with a pump to get rid of the water formed by the condensation of the steam, both the condensing-pipes and the air-pump being placed in a reservoir of cold water.