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and the flood discharges between one-half and one-third of what it actually is. In justice to myself I must say that I procured my information from Beardmore’s Manual of Hydrology, which book is considered as good authority by all English Hydraulic Engineers; but it is also necessary to say that on more carefully investigating the matter, I find that Beardmore’s gauging was not taken at the month of the Rhine, but at Lauterbourg which is some distance below Strasbourg. Is is necessary, therefore, for me to correct the statement I formerly made to the extent that the Shinanogawa discharges the same amount of water at its mouth as the Rhine does at Lautenbourg and that therefore the size of the two rivers cannot fairly be compared. In reference to the actual discharge of the Shinanogawa, it may be useful to have on the records of the Society a comparison of the results obtained by myself and Mr. Lindo as these are so close that they assuredly leave no room for uncertainty regarding it. On the 21st June 1871 I gauged the discharge of the river and found it to be 1,500,000 cubic feet per minute. During the months of June and July 1873 Mr. Lindo took a succession of observations the mean result of which was 1,320,000 cubic feet per minute, the difference between this and mine being so trifling as almost to appear extraordinary. I calculated the basin of the Shinanogawa from government maps which were necessarily more or less inaccurate, making it to be 10,000 square miles in area. And taking the discharge of that area at seventy cubic feet per minute per square mile, which is the average discharge of twenty-five rivers in different parts of the world gives the discharge of the Shinanogawa as 700,000 cubic feet per minute. Mr. Lindo has calculated the low water discharge at 720,000 cubic feet per minute, which two results verily each other surprisingly. From data procured from a comparison with other rivers I estimated that the maximum flood discharge of the Shinanogawa would probably be about twenty times the latter mentioned discharge, viz: fourteen millions cubic feet per minute, Mr. Lindo from actual measurements has calculated the flood discharge to he 12,000,000 cubic feet per minute. Those calculations, made perfectly independently on different systems and verifying each other so closely, conclusively determine the size of the Shinanogawa, and I, therefore, thought it well to give the Society the information which I do with Mr. Lindo’s sanction.
Professor Ayrton then read a resumé of Dr. Geerts’ paper on Lead and Silver; and in reply to a question from the chair, stated that he believed little or no quicksilver was found in Japan. As far as he was aware all the quicksilver used in this country was imported from China to which country it had been brought from Europe. Consequently the price of quicksilver in Japan was far higher than in England.
Mr. Brunton here remarked upon the black colour on the bronze image at Nara.
Professor Ayrton said in regard to the dark colour on Japanese bronze images referred to by Mr. Brunton, he believed