Dr. Farr on the Construction of Life-Tables. 467 



atter precedes that of the glycolic acid ; but if the monochlorinated 

 acetate of potash could be obtained anhydrous, no doubt only glyco- 

 hde would result from its decomposition. The monochlorinated 

 acetate of potash can be represented as consisting of three parts, — of 

 potassium, of oxygen, and of chlorinated acetyle. 

 C,H.C10|o 



At a higher temperature chlorine and potassium form chloride of 

 potassium. After the removal of the chlorine, the chlorinated ace- 

 tyle is converted into the biatomic radical C^ H^ O, which unites 

 with one atom of oxygen, and forms glycolide. 



V 



I 



K , 



According to its formation, the glycolide cannot contain any peroxide 

 of hydrogen, and consequently it appears that also glycolic acid can- 

 not be considered as acetic acid wherein one atom of hydrogen has 

 been replaced by peroxide of hydrogen. 



I beg to conclude with an empirical derivation of several of the 

 compounds mentioned from hydruret of ethyle. 



C, H, H, H, = Hydruret' of ethyle. 



C, H, H, O =xildehyde. 



Cj H^ O O = Glyoxal and glycolide. 



C^ O O O =Anhydrous oxalic acid. 



C,H,H,H,-FO = Alcohol. 



C, H, H, O -I- O = Acetic acid. 



C, H, O O -}-0 =Glyoxylic acid. 



C,0 O 0+0 = Carbonic acid. 



C, H, H, H,-F H, 0=C, H, O. 



C,H,H,0 +H,0= Glycol. 



C, H, O O -l-H, 0= Glycolic acid. 



C,0 O O -i-H,0=0xalicacid. 



Apirl 7. — Sir Benjamin C. Brodie, Bart., President, in the Chair. 



The following communication was read : — 



" On the Construction of Life-Tables ; illustrated by a New Life- 

 Table of the Healthy Districts of England." By William Farr, 

 M.D., F.R.S., Superintendent of the Statistical Department, Gene- 

 ral Register-Office. 



The Transactions of the Royal Society contain the first Life-Table : 

 it was constructed by Halley, who discovered its remarkable proper- 

 ties, and illustrated some of its applications. 



With better data improved methods have been found out, and the 

 form has been extended so as to facilitate the solution of various 

 questions. 



Li deducing the English Life- Tables from the National Returns, I 

 have had occasion to try various methods of construction ; and I now 

 propose to describe briefly the nature of the Life-Table, to lay down 

 a simple method of construction, to describe an extension of its form, 



2H2 



