194 



water mixed with fresh at the bottom, decompositions of oxidized 

 bodies into simpler forms of matter would take place near the 

 line where they blended. I am disposed to consider the presence 

 of organic matter, either carried in solution from the land, or 

 taken up from the silt and sand by the fresh water, as the more 

 active cause of decomposition of oxidized bodies. The forma- 

 tion of sulphurets of metals, from metallic masses which have 

 been deposited at the bottom of the sea, on soundings, is more 

 simply explained by this mode of action also. 



The existence of a drainage flow of turbid water, or a water 

 containing bicarbonate of alkalies, or alkaline earths, along a coast 

 line, would account for the green color of sea-water on sound- 

 ings near coasts. The division of blue water into many thin 

 portions between reflecting surfaces, produced by the presence 

 of suspended solid particles, alters its color to the hue which, by 

 contrast, is called green. These solid, though finely divided 

 particles, would be far more abundant in the case of the flow of 

 alkaline waters, for the mixing of such waters with the ocean 

 would be followed by the constant decomposition of the lime 

 salts of the ocean water, and the production of carbonate of 

 lime in the hydrous, gelatinous form, passing into the state of 

 opaque particles, and precipitating continuously. 



A natural cause for the production of carbonate of lime, by 

 precipitation from the lime salts held in solution by sea-water, is 

 thus acting along the coast line of this and probably other coun- 

 tries. The influence of the minute quantity of organic matter 

 contained in drainage water in producing chemical changes of 

 importance, is rendered apparent in this connection by its power 

 of decomposhion in the absence of oxygen sources. 



In tracing so much in detail the action of drainage water, 

 whether that of rivers or subterranean flow, my purpose is to 

 render this and a similar action taking place in sea-water itself, 

 a basis for some interesting generalizations which will follow. 



Prof. Jeflfries Wyman gave the measurements of the in- 

 ternal capacities of four East Indian Crania, presented 

 to the Society recently by Dr. Francis Minot. They were 

 severally as follows : — 



86 — 72 — 67 — 66 cubic inches. 



