with a Determination of the Limit beyond which it fails. 341 
binary products. I hope that he may yet be induced to furnish an account of them to 
the Philosophical Magazine. ‘The present hasty and imperfect sketch will not come to 
your hands till after the last pages of your Paper have passed through those of the 
printers; indeed, as you have authorized me, by anticipation, to send it to press as a 
concluding note to your essay, and as it is desired by the Council of the Academy to 
publish the Second Part of the Twenty-first Volume of the Transactions forthwith, you 
will, perhaps, see it first in print, and will, at all events, have no opportunity of incorpo- 
rating, on the present occasion, any remarks respecting it with your own very interesting 
communication. 
<COW sku av ede 
, “* OpsErvatTory, March 7, 1848. 
“To Professor Young.” 
