liG Scientific Intelligence, [Fe s , 



cork it so tight as to exclude the air. I have eaten green peas 

 ap.d gooseberries preserved in tliis way for a year without any 

 perceptible change, either in their appearance or taste. In the 

 last number of Nicholson's Journal (Vol. xxxiv. p. 49), there is 

 a paper by Dr. John Manners, of Philadelphia, in which he 

 relates a series of experiments, demonstrating, as he says, the 

 inaccuracy of Gay Lussac's statement. How far Gay Lussac's 

 experiments are correct, I cannot say, as- I have never repeated 

 them ; but those of Dr. Manners are quite insufficient, at least 

 to prove them inaccurate. He omits a precaution which Gay 

 Lussac says is essential for obtaining the same results as he did. 

 Gay Lussac says, that the smallest quantity of oxygen gas 

 present is sufficient to produce a commencement of putrefac- 

 tion ; and after the process has commenced, it goes on, whether 

 air be present or not. Therefore it is always necessary to expose 

 the subject of experiment to the heat of boiling water in the 

 ifirst place, in order to separate the small portion of air which 

 adheres to its surface. Now, as Dr. Manners neglected this 

 circumstance, his experiments cannot be considered as con- 

 clusive. 



IV. Constituents of Bodies. 



I have been requested by a correspondent to explain why the 

 theoretical numbei^s given in p. 6'1 of our last number do not 

 agree with those of Sir Humphrey Davy in his Elements of 

 Chemical Philosophy. The reason is, that Mr. John Davy, 

 from whom the numbers in p, 61 of our Journal were taken, 

 conceives water to be composed of one atom of hydrogen, and 

 one atom of oxygen ; and that an atom of hydrogen, of course, 

 weighs 1^ and an atom of oxygen 7*5. Whereas Sir Humphrey 

 Davy conceives water to be composed of two atoms of hydrogen 

 and one atom of oxygen. Therefore, as he makes the weight of 

 an atom of hydrogen 1, he makes, of course, that of oxygen 

 15. if the numbers in p. 61 of our last number be multiplied 

 by 2, they will coincide with those of Sir Humphrey Davy, at 

 least very nearly. 



In answer to the request made by the same correspondent, 

 that I should publish a table of the constituents of bodies, and 

 my reasons for adopting the numbers whicli I shall fix upon, I 

 have to say, that it w as my intention to give a table of this kind 

 before I received his letter; but a reason, which I cannot assign ' 

 at present, but which will appear w^hen our fifth number is 

 pubh'shed, makes it necessary for me to delay it, at least till our 

 sixth number. Such a table, in order to be useful, must be 

 preceded by an exposition of the atomic or Daltonian theory. 

 As this theory has hitherto attracted but little of the attention of 

 our London philosophers, except Dr. Vv'ollaston, it may be 



