VOL. LXV.] PHILOSOPHICAL TRANSACTIONS. 5Q5 



That Chester is healthy to a very remarkable degree, is still more clearly 

 evinced from the register of this year, than m thai of the last. In 1772, one 

 half of the inhabitants appeared to arrive at 20 years of age ; a fact which 

 seemed very surprizing when compared with the proportional mortality in other 

 towns, both of a larger and less size. But, according to this year's register, 

 one half have lived to be 36 years old. In 1772, 1 in 154^ had lived to above 

 80, and this year 1 in 13. These are very uncommon instances of longevity 

 for so large a proportion of the inhabitants. The inhabitants of St. Michael's 

 parish were numbered to be 6l8, of whom this year 10 only have died; that 

 is, a less proportion than 1 in 6 1 . If the inhabitants of the whole city were 

 numbered with the same accuracy as those of St. Michael's, many important 

 conclusions, both medical and political, might with certainty be deduced from 

 the bill of mortality. The register of burials in the Q parishes are kept sepa- 

 rate ; hence, by comparing the number of inhabitants in each parish with the 

 burials in each, for a period of years, we may, on the most evident foundation, 

 discern which part of the town is most healthy. In a political view, such an 

 account would furnish the best means of demonstrating the accuracy of a table 

 of the probabilities of life, formed from the register, and supply unerring data 

 for calculating annuities, the value of reversionary payments, and assurances on 

 lives. Such an old town as Chester, where the number of inhabitants has for 

 many years suffered little variation, and where the births and burials are nearly 

 equal, is peculiarly well fitted to furnish this important information. The 

 registers confirm the observation, that women live longer than men. Of those 

 who have lived to above 80, only 10 are males, and 17 females ; the number of 

 widowers this year is 17, of widows 44. The table of diseases of different ages 

 confirms in general the observations of last year. It is evident that no epidemic 

 visited this place in 1773 ; not one died of the measles, or miliary fever, and the 

 10 who sunk under the chincough had probably lingered under the disease since 

 the former year, towards the end of which it ceased to be epidemic. Only one died 

 of the natural small-pox; I'l were inoculated in Chester, during this year, and 

 all recovered. 



IX. Experiments on a Netv Colouring Substance from the Island of Amsterdam, 

 in the South Sea. Made by Mr. Peter Woulfe, F. R. S. p. Ql. 



This substance is of a light bright orange colour ; has a peculiar, though no^ 

 a strong smell ; and, when handled, gives a yellow stain to the skin, which does 

 not readily wash out with soap and water. Put on a red hot iron, it smokes, 

 melts, and catches fire, leaving a caput mortuum. When boiled with water, it 

 gives the liquor only a slight yellow tinge, which is but little heightened by the 

 addition of a fixed alkali ; therefore the colouring part of this substance is 



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