630 PHILOSOPHICAL TRANSACTIONS. [ANNO 1785. 



nearest to the summit of the mountain, are the lowest in the contiguous plains. 

 This will be readily conceived if the bur, made by thrusting a bodkin through 

 several parallel sheets of paper, had a part of its apex cut off by a pen-knife, and 

 is so well explained by Mr. Michell, in an ingenious paper on the Phenomena of 

 Earthquakes, published a few years ago in the Philosophical Transactions. 



And as the more elevated parts of a country are so much colder than the vallies, 

 owing perhaps to a concurrence of 2 or 3 causes, but particularly to the less con- 

 densed state of the air on hills, which thence becomes a better conductor of heat, 

 as well as of electricity, and permits it to escape the faster ; it is from the water 

 condensed on these cold surfaces of mountains that our common cold springs have 

 their origin ; and which, sliding between 2 of the strata above described, descend 

 till they find or make themselves an outlet, and will in consequence rise to a 

 level with the part of the mountain where they originated. And hence, if by 

 piercing the earth you gain a spring between the 2d and 3d, or 3d and 4th stra- 

 tum, it must generally happen, that the water from the lowest stratum will rise 

 the highest, if confined in pipes, because it comes originally from a higher part 

 of the country in its vicinity. 



//. An Account of an English Bird* of the Genus Motacilla, supposed to be 

 hitherto unnoticed by British Ornithologists. By the Rev. John Lightfoot,-^- 

 M. A. F. R. S. p. 8. 



As every discovery in natural history is esteemed worthy the notice of that 

 Society which was instituted on purpose to improve natural knowledge, I have 



* This bird is the Sylvia arundiitacea or Reed Wren of Latham, and is suspected by that author to 

 be the lesser reed- sparrow of Willoughby. 



f A short biographical account of Mr. Lightfoot was published in the year 1788 by the late Mr. 

 Pennant, who informs us that Mr. Lightfoot was the son of a highly reputable yeoman or gentleman- 

 farmer, and was born at Newent, in the Forest of Dean, in the county of Glocester, on the 9th of 

 December 1735. He was educated at St. Crypt's school at Glocester, whence he became an exhibi- 

 tioner in Pembroke College, Oxford, where he continued his studies with much reputation. He was 

 first appointed curate at Colnbrook, and afterwards at Uxbridge, which appointment he retained to 

 the time of his death. His first patron was the honourable Mr. Lane, son tothe late Lord Bingley. 

 Lord Chancellor Northington presented him to the living of Shelden in Hants, which he resigned 

 on taking the rectory of Gotham, in the county of Nottingham. He had also Sutton in Lownd, in 

 the same county ; to both of which he was presented by his Grace the Duke of Portland. His eccle- 

 siastical preferments amounted to above 5001. a year. He was also domestic chaplain to his illustrious 

 patroness the late Duchess Dowager of Portland, and by her liberality enjoyed, during her Grace's 

 life, an annuity of 1001. a year. During her Grace's summer residence at Bulstrode, he did duty in 

 the family twice a week, and at other times was of very considerable service in arranging her magni- 

 ficent collection of natural history, particularly die botanical and conchyliological part. He was an 

 excellent scholar in many branches of literature ; but after the study of his profession, he addicted 

 himself chiefly to that of botany and conchyliology, and excelled in both ; but in the former was, ac- 

 cording to Mr. Pennant, nearly unrivalled in Great Britain. 



