March, 1884.] The New _British Patent Law. 199 more brittle as the tin is increased, and at the same time decrease in strength. A slight modification of proportions often causes very great changes in the properties of the alloys, as has been noticed inNo. i, 4th series, where 0"5 per ce~t. oi' tin, added to ordinary brass, resulted in giving an alloy stronger than wrought-iron.