NUTRIENT JELLY— EXAMINATION OF WATER. 



95 



This was prepared from the thin leaf, then, when dissolved, clarified 

 by filtration or by fresh albumen. This solution melts at about 27 C, 

 or about 8o° F. ; 25 c.c. of this have been usually mixed with 25 c.c. 

 of the water to be examined, and kept for some minutes about the 



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Vr 





3 



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1 

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Fig. 49. Fig. 50. 



Fig. 49. — London waters, with 80 per cent, distilled water added 

 to gelatine sugar and sodium phosphate. Appearance presented in 

 the test-tube at the end of five days. 



FlG. 50. — London waters added to gelatine sugar and sodium 

 phosphate. Appearance at the end cf five days. (Copied from Angus 

 Smith.) 



temperature indicated, but much smaller quantities are frequently 

 sufficient." 



The water is therefore added to the gelatine in large test-tubes 

 whilst it is still fluid ; after which, as it cools, the whole mass becomes 



