TO MAKE GOOD MORTAR.

Otago Witness, Issue 1242, 18 September 1875, Page 3

TO MAKE GOOD MORTAR.

The lime ought to be pure, completely free from carbonic acid, and in the state of a very fine powder • the sand should be free from clay, partly in the state of fine sand and partly gravel ; the water should be pure, and if previously saturated with lime, so much the better. The best proportions are three parts of fine sand, four parts of coarse sand, one part of quicklime, recently slaked, and as little water as possible. There should always be enough water added at first; if water is added after slaking has begun, it will be chilled, and the mortar lumpy. The addition of burnt bones improves mortar by giving it tenacity, and renders it less apt to crack in drying.

diluted sulphuric acid, heated by steam, lne acid cleanses the surface of the metal trom rust and other impurities. The next stage is a bath of muriatic acid and ammonia, which increases the affinity of the tin and iron. The dish is now ready tor tinning, which consists simply in ££ 1 - ng {t in the molten ti n. A slight rubbing and polishing of the surface ensues, and the article is ready for the market. The process is similar with respect to other articles, such variation as there may be being more in detail than m pnnoiple."