JOHN BERNOULLI. 335 



See also Struve's SteUarum Duplicium et Multiplicium Men- 

 surce Micrometricce ...Petrop. 1837, page xci., and his SteUarum 

 Fixarum ... Positiones Medice ... Petroj:^. 1852, page CLXXXViii. 



Sir John Herschel in his Outlines of Astronomy , 1849, page 565, 

 ofives some numerical results which are attributed to Struve ; but 

 I conclude that there is some mistake, for the results do not 

 appear to agree with Struve's calculations in the works above cited. 



628. For a notice of some of the other subjects discussed in 

 Michell's memoir, see Struve's Etudes d'Astronomie Stellaire, 

 St Peter shourg, 1847. 



624. We have next to notice another memoir by John Ber- 

 noulli ; it is entitled Memoire sur un prohleme de la Doctrine du 

 Hazard. 



This memoir is published in the volume of the Histoire de 

 V Acad. ... Berlin for 1768; the date of publication is 1770: the 

 memoir occupies pages 384 — 408. 



The problem discussed may be thus generally enunciated. 

 Suppose n men to marry 7i women at the same time ; find the 

 chance that when half the 2n people are dead all the marriages 

 will be dissolved ; that is, find the chance that all the survivors 

 will be widows or widowers. John Bernoulli makes two cases ; 

 first, when there is no limitation as to those who die ; second, when 

 half of those who die are men and half women. 



The memoir presents nothing of interest or importance ; the 

 formulas are obtained by induction from particular cases, but are 

 not really demonstrated. 



625. We have next to notice a memoir by Lambert, en- 

 titled Exameri d'une espece de Superstition ramenee au calcul 

 des prohahilites. 



This memoir is published in the volume for 1771 of the 

 Nouveaux Memoir es ... Berlin ; the date of publication is 1773: 

 the memoir occupies pages 411 — 420. 



626. Lambert begins by adverting to the faith which many 

 people in Germany had in the predictions of the almanack makers 

 respecting the weather and other events. This suggests to him to 



