302 Mr Galbraith 07i the Geographical Position of 



undoubted talents, and conseqviently the final results will pos- 

 sess all the refinements which modern science can give. From 

 these we will then be enabled to deduce the true figure and 

 magnitude of the earth from British measures alone. Men of 

 science will hail the completion of these labours with great sa- 

 tisfaction, while in the accurate survey and delineation of the 

 natural features of our own country, its commercial, manufac- 

 turing, and agricultural interests will be greatly improved. 



Indeed the Coast Survey of the Firth of Clyde is now in 

 progress by Captain A. Henderson of the Royal Engineers, 

 who is provided with excellent instruments, made by Messra 

 Troughton and Simms, and he possesses all the requisite talents, 

 perseverance, and industry for such a duty in an eminent de- 

 gree. He has already fixed nearly all the more conspicuous 

 and important points, to serve as the fundamental basis whereon 

 the mai'ine surveyors must form their charts, which, when 

 finished, cannot fail to benefit greatly the shipping trade of the 

 Clyde. This gentleman's labours would, perhaps, in the mean 

 time, have terminated about Arran, had not the Chamber of 

 Commerce of Greenock, and others interested in the prosperity 

 of the trade of the Clyde, been informed of this last year, and 

 consequently very properly urged the continuation of his 

 valuable labours up as high as Greenock and Port-Glasgow, 

 which ai'e now in progress there. Under these circumstances, 

 perhaps, the results which I am now able to communicate can- 

 not possess any gi'eat and permanent value, as they wiU even- 

 tually be superseded by those more accurate determinations to 

 which I have now alluded. However, as the latter will not be 

 generally communicated to the public for some time, perhaps I 

 may be excused for troubling the Society with mine. 



The instruments which I generally carry with me for this 

 purpose, are a small altitude and azimuth astronomical circle, 

 and a good chronometer, when I can fortunately fall in with 

 one. For this I have been indebted to Mr Bryson, in the pre- 

 sent as well as last year. The circle has three verniers, each 

 reading to 10", and a good level, each division of which shews 

 8", though 1" may be estimated, if thought necessary. The 

 verniers are read by compound lenses, on the tubes of which 

 are placed reflectors supplied by Messrs Adie and Son, that 



