CHAPMAN. 31 



tific pursuits. William Chapman derived great advantage from his 

 father's knowledge of these subjects, contracting a strong taste for 

 similar occupations. After receiving a liberal education at different 

 public schools, he was put in command, at the early age of eighteen, 

 of a merchant vessel, in which he enjoyed the opportunity of visiting 

 numerous harbours, both in Great Britain and other countries. He 

 continued thus occupied for a period of three years, losing no op- 

 portunity of making himself acquainted with the circumstances of 

 the various harbours he was in the habit of visiting, and he thus 

 acquired that valuable practical knowledge on the subject of these 

 works for which he became afterwards so highly distinguished. 



After leaving the merchant service, Mr. Chapman was fortunate 

 enough to become acquainted with James Watt, with his partner 

 Matthew Boulton, and also with Mr. Wooller, Engineer to the Board 

 of Ordnance. By these eminent men he was strongly advised to 

 become an engineer, and follow as a profession that which he had 

 already closely studied as an amusement. Chapman accordingly 

 accompanied Mr. Boulton into Ireland, about the close of the year 

 1783, but although well introduced, was unable to obtain any em- 

 ployment of consequence in that country, until he had written a 

 prize essay on the effects of the river Dodder on the Harbour of 

 Dublin. Shortly after this, he was appointed resident engineer to 

 the County of Kildare Canal, the works of which were carried on 

 under the surveillance of the Duke of Leinster, the county members, 

 and other leading men. In the execution of this undertaking, Mr. 

 Chapman was requested not to alter the direction of the roads in- 

 tersected by it, although one of them deviated from the right angle 

 across the canal upwards of 50 deg. To meet this difficulty, and 

 knowing that a bridge of the ordinary construction, with any ob- 

 liquity, could not possibly stand, Chapman invented, and put into 

 practice, the method of building oblique or skew bridges, which has 

 since been so generally adopted throughout the country, in railway, 

 canal, and other bridges. Before this period, (1787), whenever a 

 road crossed the course of a canal or river, requiring the construc- 

 tion of a bridge, it had been usual to deviate the course, either of 

 the road or the object it crossed, so that the crossing should be at 

 right angles ; a practice which occasioned a great waste of land and 

 considerable expense as well as awkward and dangerous bends in 

 the roads thus treated. In some few cases where the bridge was 

 required to be of only a small opening, no alteration in the direction was 

 made, but a bridge built of an oblique form, that is with abutments 

 forming oblique angles with the road passing over it, the courses of 

 the arch being built in lines parallel with the abutments, and the 

 ends of the voussoirs bevelled off to coincide with the direction of 

 the road. Bridges built in this manner consequently became highly 

 dangerous when the span was great, or the obliquity considerable. 

 The value of Chapman's invention consists in this, that he gave the 



