CHAPMAN. 33 



became a simple process to ascertain pretty nearly the extent of 

 subsidence in any bog to be passed through, and of course to lay 

 out the line of the canal with such levels, that after subsidence, its 

 surface should be at the required depth below the surface of the bog. 



Amongst Mr. Chapman's other extensive employments in Ireland, 

 he caused, at the instance of the Irish Government, a survey to be 

 made of the harbour of Dublin to beyond the Bar at Howth ; and 

 on this occasion projected a pier from the Clontarf shore to a due 

 distance from the lighthouse, and then to the westward to a proper 

 distance from the north wall, so as to confine all the tidal water 

 covering that vast space, and to cause it to pass down the channel 

 of Pool Beg, in place of being permitted to flow inwards and out- 

 wards over the North Bull. 



In the year 1794 Mr. Chapman returned from Ireland, and fixed 

 his general residence at Newcastle-upon-Tyne. About this time the 

 great project of a canal communication between the German Ocean 

 and the Irish Sea, was engaging general attention in the North of 

 England, and Mr. Chapman was fixed upon to survey the line of 

 country for this proposed canal between Newcastle and the Solway 

 Firth. His reports on this subject, which were made during the 

 years 1795 and 1796, are still extant ; and although the work to 

 which they relate was never executed, the documents connected 

 with it are of a very interesting nature. In 1808 this project, which 

 had lain dormant for many years, was again revived, and Mr. Telford 

 was employed to survey and report upon the best line of canal be- 

 tween Carlisle and a suitable port on the Solway Firth. Although 

 Mr. Telford's plan was highly approved of, the time had not yet 

 arrived for the carrying out of even this small portion of the original 

 great scheme ; and it was not until the year 1818, when Mr. Chap- 

 man drew up a plan and report upon this line from Carlisle to Bowness, 

 that a Bill was brought into Parliament, for which an act was ob- 

 tained early in 1819. The canal which has been in successful oper- 

 ation for many years, is eleven-and-a-half miles in length, and cost 

 about 120,000. It commences on the south-eastern side of Carlisle, 

 and falls into the sea, through a height of seventy feet, by means of 

 nine locks. 



About the year 1796 Mr. Chapman became a member of the 

 Society of Civil Engineers, which at that time numbered amongst 

 its members Watt, Jessop, and Rennie, and amongst its honorary 

 associates Sir Joseph Banks, and other leading men of the day. In 

 conjunction with Mr. Rennie, Chapman was then occupied in design- 

 ing the London Docks, and subsequently the southern dock and basin 

 at Hull. He was also engaged as engineer for the construction of 

 Leith, Scarborough, and Seaham Harbours, the last named work 

 being undertaken for the Marquis of Londonderry. 



In addition to his regular professional occupations, Mr. Chapman 

 devoted a portion of his time to the publication of works bearing on 



c 3 



