446 PHILOSOPHICAL TRANSACTIONS, [aNNO 1767, 



XXXI I I. Specimen of the Natural History of the Country about the River 

 fVolga. By J. R. Forster* p. 312. 



The region of which the natural history is here given, lies on both sides of the 

 river Wolga, and extends from 48 to 51 degrees of north latitude, bordering on 

 Astrakhan and the Kuban Tartars, where it runs into the Caspian sea. But 

 though this paper is v.'ritten in a manner which shows the author to have been 

 well-informed on the subject; yet it was judged unnecessary to give an abstract 

 of it, as the information which it conveys may be easily collected from books 

 of travels and other sources. 



XXXI f^. An Algebraical Problem, and on the Evolution of a certain Mechani 

 cal Curve, among Infinite Mechanicals, luhich is solved by Determinate Equa- 

 tions. By Pius Fantoni, Professor of Philosophy and Mathematics at Bologna. 

 p. 358. 



Such mechanical curves, and their solutions, as treated of in this paper, are 

 of endless variety; and being devoid of any particular object of interest or use 

 fulness, it is not considered as of importance to be retained in this Abridgment. 



XXXV. On the Most Advantageous Construction of Water-wheels, &c. By 

 Mr. Mallet of Geneva. From the French, p. 372. 



Sect. I. The construction of such machines is very simple: they consist of 

 several planes inserted into the same axle placed horizontally above the surface of 

 the water, and in a position perpendicular to the stream. These planes, called 

 float-boards, by yielding to the action of the stream, cause the axle on which 

 they are fixed to turn round, by means of several wheels, which take into each 



* John Reinhold Forster, a celebrated linguist and naturalist, and a Prussian by birth, was bom 

 in 1729; and he died in \79S; consequently at 69 years of age. He was an ingenious, though an 

 eccentric and imprudent man; which occasioned his frequent migrations from one country to an- 

 other. In 1748 he entered the university of Halle,, in the duchy of Magdeburg, where he studied 

 divinity. He next removed to Dantzic, and commenced preacher. He afterwards went to Russia, 

 in expectation of some considerable preferment, where probably he composed the above specimen of 

 ♦he natural history of the Wolga. But being disappointed there, he next came to England, where 

 for some time he acted as tutor in the French and German languages at Warrington. In 1772 he 

 accompanied Capt. Cook in one of his voyages round the world, having procured an appointment as 

 botanist on that voyage. In 1/75 he returned to England, and was honoured by the university of 

 Oxford with the degree of LL.n. After\vards having published, contrary to the engagement entered 

 into with government, before the voyage, a botanical account of the plants discovered in that voyage, 

 be was treated with such universal coolness, that he left this country, and repaired again to Halle, 

 where he was appointed professor of natural history. In this country he was author of Observations 

 made in a Voyage round the World; and a History of Voyages and Discoveries in the Nortli; also 

 a tract on the Byssus of the Ancients; and several ingenious papers in the Phil. Trans. See also ac- 

 counts of Dr. Forster, in the Gent. Mag. for 1799, P- lti6"i and in the Monthly Mag. for IfiOO, 

 p. 934. 



