VOL. v.] PHILOSOPHICAL TRANSACTIONS. 47 1 



as soon as they have done fiUing up, its heat is choaked and stopped for the 

 time, and the other cask, which is unfilled, begins to heat. The full vessel is 

 quite open at the top, but a wooden cover is put on the vessel that is but half 

 full. The best wine makes the best vinegar; but yet they make good vinegar 

 of wine that is turned. 



The wine in changing leaves a certain grease, which sticks partly to the sides 

 of the cask, (and that they take care to do clean away) partly to the rape: so 

 that if they cleanse not the rape from it almost every year once, the wine turns 

 into a whitish liquor, which is neither wine nor vinegar. At the time when 

 they pour the wine out of one vessel into the other, a scum arises on the top 

 of the vessel, which must be carefully taken away. In the casks, which have 

 never served for this purpose before, the vinegar is made more slowly than in 

 such as have been used. 



As soon as the rape is separated from its grapes, which is done immediately 

 after vintage, it is carefully put up in barrels, lest it take air, and heat itself, 

 and be spoiled. Rape will serve a year, more or less, provided care be taken to 

 clear away every morning with a piece of linen the grease that is on the sides of 

 the vessel, and with a little broom, that which swims on the top of the liquor. 

 The rape may be freed from its grease with water, rubbing it between the 

 hands. 



An Account of some Boohs. N° 61, p. 2005. 



I. Mechanica, sive de Motu Tractatus Geometricus; Pars Secunda; in qua, 

 De Centro Gravitatis ej usque Calculo : Auth. Johanne Wallis, SS. Th. D. 

 &c. Londini, 1670, in 4to. 



In this second part the author demonstrates the nature and place of the 

 centre of gravity. He shows also, from general principles, how by calculation to 

 determine, as well the magnitude, as the centre of gravity, in innumerable sorts 

 of lines, surfaces, and solids, all right-lined figures whatsoever ; in all solids 

 bounded by plains ; in cones also and cylinders : And in curve-lined figures in- 

 numerable ; not only (with Archimedes) in the parabolar figure, but likewise in 

 all paraboloids whatever; with their ungular solids insisting on them; and their 

 conoids or other solids made by the conversion of those plains about any axe in 

 the same plain assigned ; and the centre of gravity of all these solids. And the 

 like also in other figures reciprocal to these paraboloids, infinitely continued be- 

 tween such curves and their asymptotes : Showing which of those figures, in- 

 finitely long, are of finite magnitude, and what that is; which, of infinite: and, 

 which of them have, which have not centres of gravity; and, in those which 

 have, how to assign them : And the like of the ungulas appertaining to them. 



