J34 SECURE SAILING OR LIFE BOAT, 



REMARK. 



The mistake B. H. appears to be led into an errouv by supposing, that 



confoundin °™ *^^ chances for throwing an ace in six throws of one die and 



several throws six throws of another, are'the same thing with the chance of 



one'throwTf ^ throwing an ace in six throws of two dice ; but this is not 



fereiai dice, the fact. Six throws of one die and six throws of another 



are clearly equal to twelve throws of one die, and this 



chance I apprehend will not be denied to be equal to two. 



In throwing two dice thirty-six times, it appears by the ta- , 



ble of B. H. himself, which is perfectly accurate, that the 



thrower may calculate upon throwing twelve aces, as he 



might by throwing one die seventy-two times : but here is 



the difference; in throwing one die seventy-two times, he 



has a right to reckon on an ace being turned up in twelve 



of the throws ; in throwing the two dice thirty-six times 



however, he can reckon on no more than eleven throws in 



which an ace will be turned up, because in one of the 



throws two aces will come together, and consequently one 



will be lost, which evidently cannot be the case when the 



two dice are thrown in succession. 



With regard to the throws of a halfpenny the reasoning is 

 precisely the same ; nor does Opsimath appear more inclined 

 to acquiesce in the assertion, that the chance of throwing a 

 head with one halfpenny in two throws is only J : though he 

 would probably allow this to be the true value of the chance 

 of throwing a head at one throw with two halfpence. C, 



VIII. 



Description of a secure Sailing Boat, or Life Boat. By 

 Mr. Christopher Wilson, Richard Street^ Commercial 

 Road*. 



SIR, 



H 



Neutral built JOLEREWITH you will receive drawings of a neutral 

 Ijojt^ built self-balanced boat, with an explanation, which I re- 



* Trans, of See. of Aits, vol. XXV", p. 55, The gold medal was 

 foted to Mr. Wilson for this invention. 



quest 



