ه الا الله
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read of the tin deposits of the Malay Peninsula, he concluded that they were, without exception, the richest in the world. He was aware that there was a prevailing impression here that this was not the case, but still it was perfectly true. There was no more widely distributed deposit of tín than in the Malay Peninsula, at least not of that particular kind of tin deposit which was termed stream tin. They were very widely! spread, and the deposits in themselves were prac tically inexhaustible. The lecturer proceeded to show by a map the peculiar formation of the peninsula remarking that its shape was singu- ; larly developed. There was an immense range of mountains, a few of which had been ex- plored, and some of which he was the first to explora, while others, much higher, had been effectively explored by a French gentleman who had since gone home. Some of the mountains reached a height of 10,000 feet, and there were, he believed, some even higher than that. These mountains, in about the centre of the peninsula, began to decline until they came to a part at which there was so little olerá- tion that boats might be dragged from one river to another on the opposite side. It was there the richest part of the tin deposit was to be found; there had been the greatest disturbance, and there was the greatest mineral richness. In a disputed country between the territory of Perak and Siam there were tin veins. He should speak briefly about those veins, and he might say that this was the only case he had met with where thore were veins of tin in the peninsula; olse- where, in the south, it was in alluvial deposits. This was a very important thing to bear in mind, because he had met in Hongkong several par- sous who had asked him if there was not some- thing peculiar about the tin deposits there. To these he would answer that there was nothing peculiar at all about theru, they were exactly like stream deposits all over the world-no difference. He had been asked something about pockets; he knew pockets were a subject in con- nection with mines about which people were particularly tender-laughter),—but there were to such things as poskets as they were generally understood which made them different from de- posits in other parts of the world. The deposita of tin had been accumulating for ages from the wearing down of the granite rocks. He was also asked if there were no main sources from which the tin was derived, and he answered "No, nothing of the kind was found in what was known as stream tin as far as his ex- perience went." It was most important to hear this in mind, that wherever stream tin was dis- covered, vains were not found, and where veins were found, there Win Ho stream tja. Had time allowed he could hove explained the reason of this, but he had now to confine his attention to what stream tin was. Let them suppose that they had in the mountains of the Malay Peninsula the representation of those forces which had upheaved their rugged summits, which had in course of time, through the slowly acting forces of the weather, worn into peaks and gallies as they were now seen. The rev. gentleman said his hearers must excuse him if he appeared to enter into explanations of things that seemed self evident; as he proceeded the reason would be apparent. This decomposing and wearing down of the granite by the action of the weather was owing to the iron contained in the felspar being easily rusted, and thus the granite was disintegrated till nothing was left
to represent it but heaps of fine sand. With this sand there was washed down by the force of water grains of tin that had been contained in the granite.
Whatever Was contained
in the granite was washed down into the valleys, and a great deal of alluvial granite was carried out to sea in the form of a fine mud which dis- coloured the water, but was finally deposited on the coast, and was the cause of those immense mangrove flats and mud islands that were to be found about the Malay Peninsula on the west coust. The lighter portions were carried away the furthest. and the heavier portions remained at the foot of the bills, and it was with the latter that the tin was found. It was found at the bottom of the deposit, and it might be said that if it was thus deposited it must have been only the surface of the granite which was rich in tin, and it was wasbed down first, and subse- quently covered with alluvial sand. But it would not be right to argue in this way. The granite and tin had been mingled together so generally that probably a very minute examination of the granite would have been required to perceive the tin it contained, except in exceptional instances, where it was
formed
found in little streaks, and bosses, and lumps. As to the reason of the tin being gathered to- gether in the lowest portion of the deposit, cassiteria was more than several times the weight of common quartz sand, sud sank rapidly, but its weight alone would not account for the fact. The tin was found in some ancient | stream bed-not the mere breadth the stream now occupied, as in the course of ages the stream would have travelled orer a wide valley. The mand it brought down obstructed its own course, and cansed it to constantly change its channel, and it was carried backwards and forwards across the valley and the deposit was washed much in the way it was done by artificial means. Every time the stream changed its course it washed! the sand from the alluvial deposits, and turned it over and over again, allowing the water to pass through the midst of it, so that the tin was gradually loft, and the sand, or lighter partions were carried away. It was in this way that the tin came to occupy the lowest portion of the deposit. It was covered with a deposit of alluvium sometimes as much as 30 feet in thickness, in others as much as 50 feet, but usually much less, sometimes as little as ten feet. The thickness or richness of the tin deposit bore no reference to the thickness of the deposit above it. It was merely a matter of chance, only he thought it might be inferred that where there was a thick deposit of alluvium over the tin, and the tin was not very thick, the deposit could not be of a very rich character. The audience would now understand how stream tin occurred. What occurred in Perak occurred also in Australia, and in all mines he had visited where stream tin was worked. There seemed to be an impression that the stream deposits in Perak were poorer than those in other places, whereas the fact was that if anything that they were richer. If people thought, too, there was a larger deposit of sand over the tin, that was h mistake. It would be found that in some cases there was more in Cornwall, and it was 20 also in Australia. Probably in Australis the tin deposits had not been fairly worked, for on account of labour being so very dear none but the richest mines were worked, and these were worked very differently from the mines in Perak. People asked him, again, how it was that the result of tin mining in the Malay Peninsula was so unsatisfactory if the mines were as rich or richer than those in other parts of the world. That depended upon econoinical considerations with which he could have nothing to do, but still he could form his ideas upon the subject, which might be right or might be wrong, for clergy- men were not as a rule very good men of busi- ness, and when he told his hearers what he thought about the matter at the termination of his lecture, they might take his remarks for what they were worth. Now they might consider what granite was. Its principal ingredients were mica, felspar, and quartz. but granite w$3 very rarely so simply composed as that, and in common use the name applied to a dozen different kinds of rocks having diverse obe. mical compositions. In his opinion, and in that he was following the ideas of most of the loading geologists at home, granite was formerly a stratified rock, having assumed its present form after having boen subjected to great pressure. Pressure generated heat, and with steam that was confined-of course having no means of escape- under the pressure to which the granite was subjected-produced a force which no rock was able to withstand. Superheated steam was more corrosive than any acid; they had no knowledge of any acid which melted away quarta but one, and that only to a small degree. Rocks by this process, however, were reduced to a pasty condi- tion. There was one fact about tin deposits in Perak to be noted, and that was that they were never found except at the junction of paleozoic rocks and granite. The paleozoic rocks were the most ancient stratified rocks with which they were acquainted. Now these paleozoic rocks lay on the top of the granite, and if the junction between the two was followed, it would be found that there was a gradual passage from one form to the other. Stratified rocks bore marks of stratification like sand-stone or slate, and as they were followed, down it would be noticed that these marke be. came less and loss distinct, while crystalline structure became more and more distinct until gradually there was a passage between these paleozoic rooks into granite, so that they up- peared as if the one were derived from the! other. That, however, was a matter of theory. The fact they found was that where they found minerala was always at the junction of granite or
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