Portsmouth Block Mills in 1808. The machines were of 22 types and totalled 45. They were driven by two 30 hp (22.4 kW) steam engines. The machines included circular saws, pin turning machines and morticing machines. With these machines 10 men could produce as many blocks as 110 skilled craftsmen. A pulley-block has four parts: the shell, the sheave, the pin for locating the latter in the shell and a metal bush, or coak, inserted into the sheave to save wear between it and the pin. Blocks can vary in size and in the number of sheaves. The process of making the shells
Ant on a rubber rope Ant on a rubber rope The ant on a rubber rope is a mathematical puzzle with a solution that appears counterintuitive or paradoxical. It is sometimes given as a worm, or inchworm, on a rubber or elastic band, but the principles of the puzzle remain the same. The details of the puzzle can vary, but a typical form is as follows: At first consideration it seems that the ant will never reach the end of the rope, but in fact it does. (In the form stated above, it would take 8.9 years.) Whatever the length of the rope and the