Minerals, Metals, Mining.

Thames Star, Volume XIII, Issue 4225, 17 July 1882, Page 2

Minerals, Metals, Mining.

Mr Dentoa delivered a lecture on mining on Saturday night. He said the half of this planet was composed of a gas nobody ever saw, smelt or tasted—-oxygen, the supporter of life. It has a tendency to unite with other elements, thus 8-9ths of water by weight is oxygen. Any part of a man which was not gas could be carried in his pocket without inconvenience. Silica constituted half the rock quartz. l-9th of water was composed of hydrogen, the lightest of all the elements. Sulphate of lime or gypsum is 25 per cent of' Water. 4-sths of the air is nitrogen, which is found in all plants and animals. In the coalbeds there is 70 to 80 per cent of carbon. There are very few places without gold, but not many where it will pay. The earth was once a fiery mass like the sun. It had been ascertained by means of the prism that there are in the sun sodium, copper, iron, and > a large number of element! which belong to this plinet in a state of vapor. They are burned in the atmosphere and once more return to the surface.. In this way the metals sank into the earth, the heavier going further down, and as gold is one of the heaviest there is probably plenty inside. As the crust of the earth became older it ridged up, and cracked in various places. These cracks were filled: Ist, by the injection of fluid matter poured out from the interior of the earth. 2nd. By'"sub- ' limation. When the erevicas wont down to the fiery interior, they were filled by sublimation or evaporation of the metals. 3rd. By infiltration. The hot water in the iuterior of the earth solved the quartz, silica, irpo ores, and the crevices caught whatever of these the water held in solution,,just as a kettle becomes en.crusted with lime from the water sth. By segregation caused by the great heat of the earth at one time. The rocks were folded in some places, and the minerals therein deposited in the folds byfcngregation. All the metals in the rocks came originally from the ocean, where they were held in solution just as it has been proved to hold silver and millions of tons of salt. As the rocks were formed, they came to contain the metals that were in i the ocean. As a rule gold was only found in old rocks, and in the lecturer's opinion the rocks here, are metamorphic and Silurian. They had been very much disturbed by. volcanic action, and had not cooled yet. There had been great heatjat one time, and that heat had caused segregation. The time was when the rocks where we are getting the gold was 5000 feet below the surface. The top had gradually been swept into the channel where he was snre there is an'immense quantity of gold. He had no fear that the gold would " peter out." They should follow the indications even where the reef ran only to a thread, and no doubt it would widen out. The.place would require capital for its development. He had no donbt we were only scratching the surface and that there would be mining here for thousands and tens of thousands of years.