72 Scientific Notices— 'Miscellaneous. [Jan. 



doubt this opinion; for in the month of November, 1821, he 

 observed a great number of these birds, some of which had 

 white, and others black throats ; and judging from the consist- 

 ence of the beaks and bones of them, he is inchned to beheve 

 that the former were the young, and the latter the old specimen 

 of this bird. He also observed the same difference in the months 

 of January and February of the following year. 



7. On the Change in the Weight of Eggs dating Incubation. 



MM. Prevost and Dumas have lately given a very extensive 

 paper, with numerous experiments, on the loss of weight which 

 takes place during incubation, and they come to the following 

 conclusions : — 



1. That fecundated and non-fecundated eggs suffer nearly the 

 same loss in weight during the period of incubation. 



2. That the loss follows in both cases a decreasing progression 

 from the commencement of (he incubation. 



.3. That a remarkable proportion is observed between the 

 duration of the incubation and the daily loss of weight, which is 

 so much the smaller as the period of incubation is the longer. 



4. That the loss of weight appears to depend entirely on the 

 evaporation, or rather on the chemical alterations which take 

 place in the contents of the egg, independent of the evolution of 

 the foetus, inasmuch as it is proportional to the duration of the 

 incubation, and no ways connected with the slower or more 

 rapid developement cf the young animal. — (Ann. des Sci. Nat.) 



Miscellaneous. 



8. Weis:hts and Measures. 



Our readers are probably aware of the alteration that is about 

 to take place in the standard for weights and measures, and the 

 chanoe is so considerable as to form a distinct era in the metro- 

 logical annals of this country. We subjoin the most important 

 facts connected with the subject. 



All the powers and regulations contained in the various 

 former acts, authorizing the searchmg for, seizing, and destroy- 

 ing of weights and measures not conformable to the standards, 

 are, with the penalties and forfeitures, declared to apply to 

 standards established by these acts. 



The standard of weight is the pound troy of 5760 grains, and 

 the avoirdupois pound is declared to contain 7000 of such grains. 

 The legislature has therefore made no alteration in the weights ; 

 but an alteration, to the extent of about one grain m the avoir- 

 dupois pound, has become necessary, from some supposed inac- 

 curacy in the old standards kept in the exchequer. 



The measures for length and superficies are not altered. 



The standard measures of capacity, as well for liquids as dry 

 goods, are all founded on the imperial gallon, established by 



