T. M. Reade— Denudation of the two Americas. 295 
the purposes of this calculation I take the mean discharge at 
3,105,000 cubic feet per second, or 86,250 tons=2,719,980,000, 
000 tons per annum. 
Through the good offices of Mr. E. Edmondson of Messrs. 
Gunston & Co., of this city, I have obtained a sample of the 
water of the Amazons, taken in mid-stream between the Narrows 
and Santarem in June of this year. This sample I submitted 
to Dr. Pery I. Frankland for analysis with the following result : 
PaRTs IN 100,000. 
iL is Belle age 0-98 
On Cult Gta Cae ee a er 0°38 
Carbonate of lime 2°75 
Carbonate of sia 0°22 
Sulphate of magnesia, 0°37 
Chlorate of potassium 2.0 2200002 -f0a-8 sc ass 0°23 
Chloride of sodium 0°15 
Sulphate of soda 0°13 
rganie matter O71 
Total solids in solution 5°99 
*See “On the Tertiary deposits on the Solimoes and Javury Rivers in Brazil 
by C. Barrington Brown, . Journ. Geol. Soc., 1879,” also ‘‘ Ancient River 
Deposits of the Amazons,” ibi 
+ Bates, Naturalist on the Amazons, yol. i, page 237, sa: 
may be more according to the form of the bottom. Our gratitude is due to tho 
who give us the means of checking their results. 
