486 
Birds' -Nesting. rjuly, 
formulated, and a theory of birds’ eggs be established. The 
interesting researches of Mr. Sorby into the nature and 
composition of the colouring-matter of birds’ eggs belong 
rather to the sciences of chemistry and spedtroscopy than 
to those of oology or animal physiology. What has been 
done towards an elucidation of the subjedt may form matter 
for future consideration. If this appeal should induce one 
lover of birds to take any steps to form a permanent and 
accessible record of their habits of nidification, it will have 
more than served its objedt . — The Scottish Naturalist. 
