The milk is all passed through several strainers, and then placed in great tin cans, barred across the top, and sealed. They are deposited in a van, which starts from the Farm about three in the morning, and arrives at the dairy, in Farringdon-street, between three and four. The seals are then carefully examined, and taken off by a clerk. In come the carriers, commonly called "milkmen," all wearing the badge of Friern Farm Dairy; their tin pails are filled, fastened at top, and sealed as before, and away they go on their early rounds, to be in time for the early-breakfast people. The late-breakfasts are provided by a second set of men. Such are the facts we have ascertained with regard to one of the largest of the great dairy farms near London. SAILING IN THE AIR.--HISTORY OF AERONAUTICS. Aeronautics, or the art of sailing in the air, is of very modern date; if, indeed, we are warranted to say that the art has yet been acquired, for we have only got a machine or apparatus capable of sustaining some hundreds of pounds in the air, the means of guiding and propelling it having yet to be discovered. The attention and admiration of men would doubtless be attracted from the beginning to the ease, grace, and velocity with which the feathered race soar aloft, and wing their way in the upper regions; but there is no reason to believe that any of the nations of antiquity--not even Greece and Rome, with all their progress in science and art--ever made the smallest advances toward a discovery of a method of flying, or of aerial navigation.