31 



twenty-three lighthouses, including that of the Bell Rock ; and 

 through his indefatigable zeal and patient skill, the catoptric system 

 of litrhthouse illumination was in Scotland brought to a state of per- 

 fection which has not elsewhere been equalled. Many of those im- 

 provements he was the means of extending to the lighthouses of 

 Ireland and of some of the colonies. He also invented two valuable 

 additions to the mode of distinguishing lights on a coast, known as 

 the intermittent and fiashing lights, the latter of which, in parti- 

 cular, has been generally approved by seamen ; and so much was 

 the late King of the Netherlands pleased with the arrangement and 

 effect of this distinction, of which he had read an account, that he 

 sent to Mr Stevenson a gold medal as a mark of his approbation. 

 The memoir next notices Mr Stevenson's career as a practitioner in 

 his profession of a civil engineer, in the course of which it is not per- 

 haps generally known that he designed and executed the eastern 

 approach to Edinburgh by the Calton Hill ; and, after alluding 

 to several of his works in bridges and harbours, it mentions his 

 improvements in the construction of timber and suspension bridges, 

 and notices his connection with the first introduction of the railway 

 system into Great Britain, and his contributions to various scientific 

 j ournals, and to literature of his own profession. In conclusion, the 

 writer briefly touches upon the private character of his father, and 

 the esteem in which he was held by all who knew him, and more 

 especially by the Commissioners of the Northern Lighthouses, who, 

 in 1824, ordered his bust to be placed in the Bell Rock Lighthouse, 

 and, on the occasion of his death, recorded in the Minutes of the 

 Board their respect for his talents as a public oflRcer and his virtues 

 iis a man. 



2. Historical Notice of the Progress of the Ordnance Survey 

 in Scotland. By Alexander Keith Johnston, Esq. 



There are few places on the earth's surface which, within such a 

 limited area, combine so many of the requisite elements for charto- 

 graphic delineation as are met with in Scotland. With mountains 

 rising almost to the limit of the snow-line, and an extensive sea- 



