lit Royal Society. 



The author concludes by noticing these accidental errors in his 

 tabulated results, and by a statement, in a tabulated form, of the 

 correct latitudes and lengths of the pendulum at the several stations. 



A paper was also read, entitled, " On the eifects produced on 

 the air-cells of the lungs when the circulation is too much increased ; 

 by Sir E. Home, Bart. V.P.R.S." 



June li. — W. J. Guthrie, Esq. was admitted a Fellow of the 

 Society ; and a paper was read, entitled, " On the ultimate com- 

 position of simple alimentary substances ; with some preliminary 

 remarks on the analysis of organized bodies in general ; by W. 

 Prout, M.D. F.R.S." 



This is the first of a series of communications on the same sub- 

 ject which Dr. Prout intends to present to the Royal Society ; the 

 object of the whole being to determine the exact composition of 

 the saccharine, oily, and albuminous divisions in which the ali- 

 mentary substances of the higher animals may be comprehended; 

 and then to inquire into the changes which are induced in them, 

 during the subsequent stages of assimilation, by the stomach and 

 other organs. In the present paper are given some preliminary 

 observations on the analysis of organized bodies in general, together 

 with the composition of the saccharine substances. Dr. Prout ob- 

 served, whilst stating the difficulties attending the use of oxide of 

 copper, as now employed in the analysis of organic substances, that 

 it is not only hygrometric, but, like many other powders, also con- 

 denses air. He also found that when it was removed from the tube 

 in which the combustion had been effected, and re-triturated and 

 re-burnt, it almost invariably gained in weight ; a circumstance 

 which he ascribed partly to the combination of the oxygen of the air 

 contained in the tube with the partially reduced oxide of copper. 



These sources of error Dr. Prout has been enabled to obviate 

 by means of the following well-known chemical facts. When 

 we burn in a given quantity of oxygen gas a substance com- 

 posed of hydrogen, carbon and oxygen, one of three things must 

 happen. Either the volume of the gas will i-emain unchanged, in 

 which case the hydrogen and oxygen must exist in the substance 

 in the proportions in which they form water ; or the volume may be 

 augmented, in which case the oxygen must be in excess ; or lastly, 

 the volume may be diminished, when the hydrogen must exceed that 

 proportion. The author then proceeded to describe the apparatus he 

 employed for the purpose of determining the composition of vege- 

 table substances on these principles ; and also detailed some precau- 

 tions necessary to be observed in the process, pointing out at the 

 same time some of its peculiar advantages, the chief of which is that 

 it is not liable to be affected by moisture. Dr. Prout next considered 

 the composition of the saccharine principle, under which term he 

 included all those substances in which hydrogen and oxygen exist in 

 the proportions in which they form water. These were stated to be 

 all alimentary, or capable of becoming so, and were termed by way 

 of distinction vegetable aliments. Sugar was first examined, of which 

 at least two distinct varieties, and probably many more exist. The 

 most perfect form of this principle is sugar-candy prepared from 



cane- 



