4 IS Additional Notes. 



spoken of, by the writer of the preface, as possessing great natu- 

 ral endowments, with but little cultivation j and as deserving to 

 be ranl:ed, as well as his father, among the curiosities of Penn- 

 s}l\ania. — MS. Letter of the Rev. Dr. Elliot, qf BostoUj to the 



Author. 



It is worthy of notice, that the use of the quadrant in que- 

 stion was confined to the English nation until the year 1736, 

 when M. d'Apres de Mannevillette, the great maritime geo- 

 grapher, employed it on board a French ship 5 and on his return 

 to France, one of the earliest objects of his attention was to 

 state, in a public print, his high estimation of this curious in- 

 stmment. He thus had the honour of introducing to his coun- 

 trymen one of the most valuable inventions of the age. 



Note (T), p. 101. — Dr. Priestley concluded from his experi- 

 ments, and it has been since generally believed by Ingenhousz, 

 Sennebier, and other vegetable physiologists, that vegetables, in 

 the course of their germination and growth, when exposed to 

 solar light, absorb azote and emit oxygen, and thus purify the 

 surrounding air. But, by a series of ingenious experiments 

 lately published, professor Woodhouse, of Philadelphia, has 

 drawn into question tlie truth of these conclusions. From the 

 result of these experiments, he contends that the germination of 

 seeds and the growth of plants do not purify atmospherical air 3 

 but that, whenever they appear to afford oxygen gas, it is by 

 devouring the coal of carbonic acid gas for food, and leaving its 

 oxygen in the form of pure air. He has also made experiments 

 on the effects produced by the leaves of plants in common air, 

 impregnated with carbonic acid gas, and exposed to solar light , 

 in which cases the carbonic acid disappeared, and the oxygenous 

 gas increased. And from trials made with the fresh leaves of 

 many different plants, exposed to sunshine in pump-water, river- 

 water, and this latter charged with carbonic acid, he is confirmed 

 in the same conclusion. Dr. Woodhouse, therefore, denies that 

 vegetables either decompose water, emit oxygen, or absorb 

 azote, as has been some time commonly believed. — Nicholson? 

 Philos. Journal, 8vo. series, vol. ii. for July 1$02, 



Note CU)y p. 1 II. — ^The important services of M. Lavoisier, in 

 forming tlie theory of the French academicians, and the intrinsic 



