Natural History, 8fc. 435 



The annual produce of gold in Europe and in Asiatic Russia 

 amounts to 26,500 marks of gold, and 292,000 of silver, of which 

 the Russian empire alone yields 22,200 marks of gold, and 76,500 

 of silver *. 



24. ON THE CHANGE WHICH THE AIR IN EGGS UNDERGOES 

 DURING INCUBATION. (Professor Dulk, of Kcenigsberg.) 



This philosopher has lately made some analyses of the air in the 

 large end of the egg at different periods of incubation, and the follow- 

 ing is the result of his inquiries. 



Before incubation, the air contains considerably more oxygen than 

 atmospheric air, the oxygen in the former being found, at two dif- 

 ferent experiments, 25.26 and 26.77 ; and that in the latter, on the 

 day of the experiments, only about 21.0 t. 



On the tenth day of incubation the air was found to contain 22.47 

 of oxygen, and 4.44 of carbonic acid ; the absolute quantity of oxygen 

 is accordingly nearly the same, but 4.44 of it has united with carbon. 



On the twentieth day, the quantity of air in the egg was found to 

 be nearly eight times as large as before incubation ; the analysis gave, 

 at four different experiments, 



Carbonic Acid. Oxygen. 



9.40 



9.23 . . . 17.55 



6.19 . . . 



8.48 . . . 17.90 



where the absolute quantity is the same as in the former experiments, 

 but the quantity of carbonic acid is increased ; that of the third ex- 

 periment, being only 6.19 per cent., corresponds, however, in some 

 degree, with the result of the other analyses, as the chicken had 

 apparently died a considerable time before the experiment was 

 made J. 



* PoggendorfPs Annalen, 1830. p. 273. 



f Though this result is somewhat at variance with that obtained by M. Bischoff, 

 according to whom the mean quantity of oxygen before incubation is only 23.475, 

 the experiments of both philosophers agree, inasmuch as both show that the air 

 of fresh eggs contains more oxygen than atmospheric air. 



+ From Schweigger-Seidel's Jahrb. der Chemie und Physik. 



