tfg SCIENTIFIC NEWS* 



very pure alcohol, which you will distribute over the oily 

 tnass by inclining the glass in different directions with a. 

 very gentle motion. In this way you will effect their incor- 

 poration. Repeat this operation by little and little, till the 

 varnish is reduced to a proper degree of fluidity. Remem- 

 ber, the first drops of alcohol are the most difficult, and re- 

 quire the longed time to incorporate; and that the difficulty 

 diminishes as each successive addition is incorporated, or as 

 the mass approaches the state of saturation. 



When the varnish has attained the suitable degree of 

 fluidity, it is to be suffered to stand a few days; and when 

 it has become very clear, the varnish is to be decanted off. 



The magma that remains at the bottom may still be 

 rendered useful, by pouring on alcohol in the manntr 

 directed above; but care must be taken, to add very little 

 at a time. 

 Uses of the This varnish is made without heat, is very clear and co- 



▼arnish. lourless, may be applied with equal success on pasteboard, 



wood, and metals, and may be worked and polished with 

 ease, indeed better than any known varnish. It may be 

 used on paintings, and singularly heightens their beauty. 



SCIENTIFIC NEWS. 



French National Institute. 



French na- A HE public sitting of the Mathematical and Physical 

 tional Insti- Class for 180Q was held on the 2nd of January. A double 

 Question for a P v ' ze nad keen offerecl for a " Theory of the perturbations 

 double prize, of the planet Pallas, discovered by Dr. Olbers : or in gene- 

 ral the theory of planets, the excentricity and inclination of 

 which are too considerable for their perturbations to be cal- 

 culated with sufficient precision by the known methods." 

 Not to enter into any thing more than is indispensable, on 

 buch a difficult subject, nothing was required farther than 

 algebraic formula?, but so arranged, that an intelligent cal- 

 culator might apply them securely, and without mistake, 

 either to the planet Pallas, or to «ny other already discover- 

 ed, or that may be discovered hereafter. Notwithstanding 

 these restrictions, no paper having been sent, the subject is 



jtiH 



