It has also been advocated with signal ability by Donald McKay of Boston, one of our most eminent naval constructors, who, after building the Great Republic, the Flying Cloud, and a fleet of other celebrated clippers, has visited the dockyards of France and England, examined their mail-clad ships upon the stocks and those already finished.

In practice, however, these theoretical results are not to be trusted, until they have received such modifications as will make them representative of the practice of the most experienced constructors.

Sir Thomas Bell, who possessed great experience of shipbuilding in a private capacity, was at the head of the Department of the Deputy Controller for Dockyards and Shipbuilding, and the Director of Warship Production was a distinguished Naval constructor.

Among the subscribers, was Mr. Rowley, the memorable constructor of the orrery; and among my favourers was the lord Piesley, a title not unknown among magnetical philosophers.

Referring to column 4, and accepting the case of water flowing through a smooth tube as analogous to that of a current flowing within a large body of water, it appears that the inclination necessary to give the highest resultant pressure is an angle of 49 deg., and this corresponds closely enough with the angle which practical constructors of screw propellers have found to give the best results.

Mr. Winslow was one of the most ingenious hotel constructors in the West.

It has also been advocated with signal ability by Donald McKay of Boston, one of our most eminent naval constructors, who, after building the Great Republic, the Flying Cloud, and a fleet of other celebrated clippers, has visited the dockyards of France and England, examined their mail-clad ships upon the stocks and those already finished.