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Tin in Missouri
376
Editorial Correspondence.
glass of the little telescope. This slit limited the light entering the telescope to that of the refrangibility of the part of the spectrum immediately about the bright line coincident with c. The slit of the spectroscope was then widened sufficiently to admit the form of the prominence to be seen. The spectrum then became so impure that the prominence could not be distinguished. _ _ A great part of the light of the refrangibilities removed far from that of c was then absorbed by a piece of deep ruby glass. The prominence was then distinctly perceived,--something of this form. A more detailed account is not now given, as I ~ - ...... "-++" think I shall be able to modify the method so as to make the outlines of these objects more easily visible.
TIN IN MISSOURI,
Prof. Henry J[orton. DE.(R SIR:---From an examination of the supposed tin region, from which I have this day returned, I am surprised that the district has not received the attention it deserves from the mineralogists and metallurgists of this country. I have found that the various trappean injections associated with the pre-selenian rocks of South-East Missouri (and cotemporaneous with the formation of the Pilot Knob and Iron Mountain ore deposits,) are more or less charged with stannic acid, and that the granites which they penetrate, have also been influenced to such an extent that they show small amounts of tin. Several assays conducted on the ground with extraordinary care, and of samples drawn by myself from the deposits, have shown an amount of tin ranging between 0"4 per cent. and 1"78 per cent. In the next number of the Journal, I propose, with your permission, to give a fuller account of the mode of occurrence of the deposits, as well as of their lithological characters, accompanied by full analyses of samples brought by myself from the locality. Very respectfully yours, CHAs. P. WlLLIX~IS. Philadelphia, June 2d, 1869.
Editorial Correspondence.
glass of the little telescope. This slit limited the light entering the telescope to that of the refrangibility of the part of the spectrum immediately about the bright line coincident with c. The slit of the spectroscope was then widened sufficiently to admit the form of the prominence to be seen. The spectrum then became so impure that the prominence could not be distinguished. _ _ A great part of the light of the refrangibilities removed far from that of c was then absorbed by a piece of deep ruby glass. The prominence was then distinctly perceived,--something of this form. A more detailed account is not now given, as I ~ - ...... "-++" think I shall be able to modify the method so as to make the outlines of these objects more easily visible.
TIN IN MISSOURI,
Prof. Henry J[orton. DE.(R SIR:---From an examination of the supposed tin region, from which I have this day returned, I am surprised that the district has not received the attention it deserves from the mineralogists and metallurgists of this country. I have found that the various trappean injections associated with the pre-selenian rocks of South-East Missouri (and cotemporaneous with the formation of the Pilot Knob and Iron Mountain ore deposits,) are more or less charged with stannic acid, and that the granites which they penetrate, have also been influenced to such an extent that they show small amounts of tin. Several assays conducted on the ground with extraordinary care, and of samples drawn by myself from the deposits, have shown an amount of tin ranging between 0"4 per cent. and 1"78 per cent. In the next number of the Journal, I propose, with your permission, to give a fuller account of the mode of occurrence of the deposits, as well as of their lithological characters, accompanied by full analyses of samples brought by myself from the locality. Very respectfully yours, CHAs. P. WlLLIX~IS. Philadelphia, June 2d, 1869.