115 CAlCULATfON OP CHANCES, &C. 



verted into a oxide of lead, with a few particles of iron and tin. From 



ona e, \\^\s^ and the circumstances under whicli it appeared to have 



been formed, he concluded, that the metals forming the 



solder were oxided by the air throut^h the influence of the 



alkali, and that at the same time the carbonate of potash 



WeVand dlf-'^' ^^^ ^^^" decomposed ; that is to say, the alkali had united 



solved. with the tin, and the carbonic acid with the oxide of Uad. 



Oxides of tin This conjecture he verified by a direct experiment, taking 



th'^ d*** ^°S®' nearly equal parts of oxide of tin and oxide of lead, and 



pose carbonate heating them slightly with a solution of carbonate of potash, 



of potash, 'pjje f^j^ ^as dissolved, and the lead carbonated. 



VII. 



J^xample of a Calculation in the Doctrine oj' Chances; a Tide 

 Table; and Remarks on the breaking of Waves, In a Let'^ 

 ter from a Correspondent, 



To Mr. NICHOLSON, 

 SIR, 



Jt^ Friend of mine, who has been spending the summer ai 

 a watenng place, has proposed to me some questions, which 

 arose out of the amusements of the season, but which it re- 

 quired some little consideration to answer in a satisfactory 

 manner. If you think the results of my reflections likely 

 to be Interesting to your readers, they are much at your ser- 

 vice. 

 "What is the !• The first question was how to determine the chance of 



chance of win- winning a raffle, when you have thrown a given number. It 

 a'given^num-'^ is usual to throw three times, with three dice; the highest, 

 ber thrown? or sometimes the lowest, wins ; and if two or more persons 

 throw the same number, they must raffle again among 

 themselves. We must first calculate the chance, that none 

 of the persons who are to throw will throw higher; and then 

 the chame, that, if they da not, any one of them will tlirow 

 the same number, or any two, three, or more; but as thjs 

 caiculati6h cannot easily be made during the time of rat- 

 f!ihg, I have made a table which is sufficiently accurate for 

 the purpose. 

 r:^ . A Talk 



