Tt may be assumed as certain that there lias been some drifting 

 of popiiktion from Adelaide and its subui'l)s. But as the 

 Registrar-General had no data enabling liim to determine how 

 great had been tlie loss of population so produced, he was com- 

 pelled to follow the usual course in framing liis estimates year by 

 year. The population of tlie city and suburbs is thus represented 

 as having increased from 103,864 in 1881, the census year, to 

 128,377 in 1886. It is more than probable that there has been 

 no such increase, and I venture to suggest a means of calculating, 

 with an approximation to accuracy, what the actual population 

 numbered in 1885 and 1886. The calculation is based on the 

 assumption that the birth rate is nearly a fixed quantity from 

 year to year, and, as a matter of fact, the fluctuation between 

 1881 and 1884 was only from 42-17 to 42-89 per 1,000 of the 

 population. The sudden fall to 33-61 per 1,000 in 1885, and to 

 28-24 in 1886 can hardly, therefore, be taken as correctly repre- 

 senting the true condition. It is true that hard times may lead 

 to a lowering of the birth rate, in part directly, though chiefly 

 by lessening the number of marriages ; but such an effect is not 

 likely to be so rapid or so marked in Australia as in countries 

 less favourably situated. Without claiming absolute accuracy 

 for the calculations here presented, I venture nevertheless to in- 

 sist that they offer a nearer approach to the true numbers than 

 official estimates. Taking the population and the number of 

 births in 1881 as showing the true proportion, and assuming that 

 there was a similar proportion existing in 1885 and 1886, a 

 simple rule of three calculation gives the following results. The 

 births in 1881, to the number of 4,424, corresponded to a popu- 

 lation of 103,864, and therefore 4,270 births in 1885, and 3,626 

 births in 1886 may be taken as representing a population of 

 100,248 in 1885, and 85,129 in 1886. And having obtained an 

 approximately correct population basis we are in a position to 

 •calculate, with a similar approximation to accuracy, the true 

 death rate in the same years, viz., 18-17 per 1,000 in 1885, and 

 21-59 per 1,000 in 1886. If the two years are taken together, 

 to eliminate accidental variations, the rate is found to have 

 averaged 19-74, or rather less than the average of the three 

 previous years, 1882-84, which was 21-11, and almost the same as 

 the most favourable of the ten previous years, viz., 1877, with a 

 rate of 19-71. 



AVhile it seems probable, therefore, that there has been some 

 reduction in the death-rate in 1885 and in 1886, it must also be 

 regarded as certain that the reduction lias not l^een nearly so 

 great as is shown in the official estimates. 



But the influence of sanitary improvements on the health of 

 the population may be shown in a different way. There are cer- 



