TO THE ORIGIN OF LIFE 49 



In describing the synthetic results with the ferric oxide colloid, 

 a few earlier experiments made in glass vessels with rather poor 

 daylight illumination may be passed over, merely remarking that 

 these led us on to the others in which unmistakable evidence of or- 

 ganic synthesis was obtained, and only the latter are here recorded. 

 With sufficient illumination either with sunlight or the mercury 

 arc spectrum, and especially when " Uviol " glass or quartz has 

 been used, we have never failed to obtain clear evidence of 

 synthesis. 



Experiment I. A dilute solution of colloidal ferric hydroxide 

 containing 0-2 per cent, of Fe 2 3 , was placed in a thin blown flat- 

 sided glass bottle, made like a wash-bottle with ground-glass 

 stoppers. A slow current of carbon dioxide, washed by passing 

 through a wash- bottle containing water, after evolution from marble 

 in a Kipp apparatus, was passed through the colloidal solution during 

 two days of fairly bright sunshine on the laboratory roof. On 

 distillation this gave a moderately strong positive reaction to the 

 SchifJ's test. 



Experiment II. A glass soda-water syphon with a " sparklet " 

 apparatus attached was charged with 500 c.c. of distilled water and 

 5 c.c. of a colloidal ferric oxide solution, and after dilution contained 

 about 0-05 per cent, of colloidal ferric oxide. This was saturated 

 with carbon dioxide by a sparklet bulb, and left on the roof for a 

 period of twenty days, in which there were about thirteen days of 

 bright sunshine. At the end of the period, 40 c.c. were withdrawn 

 and distilled. A very distinct positive reaction for formaldehyde 

 was obtained with Schryver's test. 



Experiment III. : Exposure to Sunlight in Transparent Silica 

 Flask. A colloidal solution of ferric hydroxide of a concentration 

 of 0-14 per cent., measuring 50 c.c., was placed in a silica flask 

 through which carbon dioxide was passed, on the roof. The ex- 

 periment lasted for two days, of which the first was dull, and the 

 second almost continuous bright sunshine. On distillation this 

 gave a most marked positive reaction with Schiff's test, indicating 

 from the short period of exposure that the reaction probably pro- 

 ceeds more rapidly in silica vessels which are more transparent to 

 the shorter wave-lengths of light. 



Experiment IV. : Exposure to Mercury Arc Lamp with " Uviol " 

 Glass Shade. A colloidal solution of ferric hydroxide diluted 1 in 20 

 from a stock solution of 2-26 per cent., and hence containing 0-113 



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