After writing the foregoing, I received a volume issued annually by the United States Geological Survey on the Mineral Resources of the United States for 1886; and on page 364 I read with surprise the following statements in regard to the Newcastle mines of Washington Territory: "Considerable iron pyrites is present in this coal, which fact, added to the chaff-like character of the coal for igniting, causes much annoyance and cost to the mine from fires. Coal, or the mine refuse, piled in large quantities quickly ignites." I knew when I was in the Territory that the mine was on fire, as I have heretofore stated; but I heard no intimation of spontaneous combustion. In fact, I was told that it was accidental. I wrote at once to Mr. David T. Day, of the Government Survey, who is the present editor of this valuable work, asking his authority for such statements concerning this mine as had never, so far as I knew, been made before; though the mines have been described, or mentioned, in all the preceding volumes of the same work, and were mentioned with approval by Bailey Willis, Goodyear, and all other writers on the resources of Washington Territory. Moreover, that I had spent weeks in the neighborhood of the mines, and never heard anything of iron pyrites or spontaneous combustion. Mr. Day replied that he had no personal knowledge on the subject; but that those statements had been furnished him by Mr. James F. Jones, who is connected with some mining operations along the Northern Pacific Railway. I wrote also to Mr. F. H. Whitworth, of Seattle, calling his attention to the above statements, and asking what was the truth of the matter. I received his reply just in time to insert in this Report. I copy below all that he says on the subject, which puts a different face on the matter. [Sidenote: Correction by Mr. Whitworth.]