In this way continuous working has been rendered possible, whereas formerly operations had to be stopped every twelve or fifteen hours to allow the over-heated blocks and furnace to cool down.
He continued his scientific correspondence with unbroken interest and undiminished logical acumen; he thought out the application of the pendulum to the regulation of clockwork, which Huygens successfully realized fifteen years later; and he was engaged in dictating to his disciples, Viviani and Torricelli, his latest ideas on the theory of impact when he was seized with the slow fever which in two months brought him to the grave.
The earliest known description of Athens was that of Diodorus, o ireptryris, who lived in the second half of the 4th century B.C. Among his successors were Polemon of Ilium (beginning of 2nd century B.C.),whose great irepco)ynvcs gave a minute account of thevotiveofferings'on the Acropolis and the tombs on the Sacred Way; and Heliodorus (second half of the 2nd century) who wrote fifteen volumes on the monuments of Athens.
I haven't heard that name in fifteen years.
Thousands of Alpine glaciers from one to fifteen miles long fill the upper valleys and canyons of the mountains.
They walked for fifteen minutes before the tunnel intersected with another.
The sum which they agreed to pay him was only fifteen hundred guineas; and out of this sum he had to pay several poor men of letters who assisted him in the humbler parts of his task.
Having determined to make chemistry his profession, at the age of fifteen he entered the shop of an apothecary at Appenheim, near Darmstadt; -but he soon found how great is the difference between practical pharmacy and scientific chemistry, and the explosions and other incidents that accompanied his private efforts to increase his chemical knowledge disposed his master to view without regret his departure at the end of ten months.
In the spring of 1833 the store's stock was sold to satisfy its creditors, and Lincoln assumed the firm's debts, which he did not fully pay off for fifteen years.
At the age of fifteen Prince Peter Kropotkin, who had been designed by his father for the army, entered the Corps of Pages at St Petersburg (1857).