Proceedings of the Royal Institution, 377 



mean intensity of the light afforded by a ball of lime about the size of 

 a large pea' was equal to about eighty wax candles. The audiencie Had 

 a very striking proof of the accuracy of this statement, by observing 

 iliat, though the lecture-room was brilliantly illuminated with gas, 

 tte uHadows of the large chandelier and other objects were thrown on 

 the walls, apparently as dark as if the ignited ball of lime had been 

 %'e only light present. The lecturer concluded by examining the 

 'mefliods proposed for ascertaining the force of the sun's radiation, &iA 

 shewed that none of those methods are sufficient for determining 

 with any degree of accuracy the direct force of the.sun*B zadiatioa ait 

 different heights, and in different latitudes, -"-^^no.-r.'^b yUr,jh lovn^jol 

 ^^'^ ''-■■-' ••>:ii -J .! i^C'Yqqc rni ffoiv^ffiiw ba'(oI(f 



^^^^^' M^cH26ih:^ '-'-----'' -''-'-^ 



Mr. Brooke, On the Methods of constructing Tables of Lives, from 

 which the Value of Annuities and Reversions might be computed. — Mr. 

 Brooke began by explaining the method of forming such tables from 

 parochial registers ; from which it appeared, that the lives embraced 

 by tables so formed, are not selected, but taken promiscuously at their 



.births ; and that the number living at every age, according to these 

 tables, must consist of both sick and healthy persons. The lecturer 

 argued, that such tables were therefore unfit to be used in computing 

 the value of annuities on healthy lives. Hence it becomes an im- 

 portant object to construct other and more correct tables for this pur- 

 pose ; and as the lives of the annuitants themselves appeared to 

 afford the most certain data for estimating the average duration of 



, such lives, on the supposition that the average state of health of this 

 class of persons, at the time of their becoming annuitants, would not 

 differ much in different individuals, it was stated, that several tables 

 of such lives had been constructed within the last few years. 



It was then shewn, that an increase had taken place in the popu- 

 lation of the country, between 1801 and 1821, amounting to more 

 than on^third of the number of inhabitants contained in the census 

 of 1801 ; and that it was probable that the number at this time would 

 be t9 that of 1801, as 3 to 2, or ^ more ; an increase which might 

 alpn^ (observed the lecturer) be expected to produce much of the 

 distress now complained of. THq, increase in the population of Lon- 

 don hadjjQO^^ appeared, k^t pace with that of the kingdom at 



