1823.] of the Egg during Incubation. 101 



subject and various accidents have prevented me from complet- 

 ing them till the present time ; and the results, which, after all, 

 are much less perfect than I could wish, I have now the honour 

 of submitting to the Society." 



Preliminary Experiments on the Egg in its recent and unal- 

 tered State. 



It is here stated, that " the specific gravity of new laid eggs 

 has been found to vary from 1-080 to 1-090; " and their appa- 

 rent diminution in specific gravity is shown to depend " on the 

 substitution of air for a portion of the water of the egg which 

 escapes." A table is given, showing the gradual loss of 

 weight of an egg during a period of two years. The original 

 weight on the 19th May, 1820, the day it was laid, was 907-5 

 grains ; and on the 19th of May, 1822, it had become reduced 

 to 363-2 grains ; having sustained a loss of 544-3. 



" Hence we learn," says the author, " that a moderately 

 sized egg loses on an average about -75 grain in 24 hours, and 



that uniformly during a very long period On being broken, 



the whole of the contents of this egg were found collected at the 

 smaller extremity in a solid state ; but on being put into water, 

 they absorbed a large portion of that fluid, and assumed an 

 appearance not much unlike those of a recent egg ; the smell 

 also was perfectly fresh." 



" The relative weights of the shell, albumen, and yelk of 

 different eggs," continues Dr. Prout, " are very different. With 

 the view of investigating this point, and of obtaining something 

 like an average, the following experiments were made. The 

 eggs were boiled hard in distilled water, and the different parts 

 weighed immediately in their moist state." 



A similar table is then given, in which the weight of each of 

 these eggs is supposed to be 1000 grains; and Dr. Prout thus 



