ZOOLOGY. 361 



the water evaporates under the sun's rays, the earthy salts dissolved by 

 the acid fluids below are left in the interstices existing in the sand like 

 deposits of food remains until they are filled and every trace of granules 

 obliterated. The increased amount of sulphate of lime, the uniform acid 

 state of these guanos and cavities lined with crystals, are all according facts 

 in favor of the conclusion adopted. The experiments, in their extended 

 application to other aggregates, are proving that many compact rocks may 

 be formed at common temperatures, by a similar action, not always in- 

 volving a chemical solution of the materials. 



RE3IARKABLE CHANGE IN THE COMPOSITION OF THE COCHITU- 

 ATE WATER SUPPLIED TO THE CITY OF BOSTON. 



Dr. A. A. Hayes, at a late meeting of the American Academy, read a 

 paper on the subject of the chemical changes -which have taken place in 

 the composition of this water. 



Prior to the 1st of November, his weekly testings of this water showed 

 that the ordinary products of humic decomposition did not appear, while 

 crenic acid and crenates became very abundant, at one time exceeding 

 nineteen times the weight of the minimum quantity. An earthy odor ac- 

 companied the change, and this was soon replaced by an odor resembling 

 that of fish, or fish oil. Analysis showed the presence of an oxidized oil, 

 while the odor could be condensed from the vapor of the water and ex- 

 hibited apart. This condensed in water would putrefy in the lapse of a 

 few days, and the water itself enclosed would rapidly undergo fermentative 

 changes, the oil remaining. 



Repetitions of the experiments on the water soon proved that even coarse 

 filters of cloth would remove matter from the water, which was evidently 

 the source of the peculiar fish-like odor, often confounded with the taste. 

 The more accurate separations were made by means of displacers, filled 

 w r ith powder of animal charcoal recently calcined. All the water entering 

 the charcoal was previously strained, and the charcoal, without removal, 

 was lightly washed with alcohol, and the latter displaced by ether, when a 

 solution of yellowish or brownish fatty matter was obtained. This had 

 the odor of fish oil, but was in the state of a mixture of oily acids, united 

 to a base, either lime or ammonia, often a true adipocere. Acids elimi- 

 nated a fluid oil, of about the same sp. gr. as lard oil, readily soluble in 

 carbonate of soda solution, forming soap ; alcohol dissolved it freely also. 



The water was meantime changing the composition of its organic mat- 

 ter, the usual apocrenates becoming less rare and the quantity of organic 

 matter diminishing. Oxygen gas also appeared in far larger quantity, 

 but the odor and oil still continued to infect the water. 



Late in December it was found that an enormous increase of animal- 

 cules took place, the cyclops and daphnia predominating, although the 

 temperature of the water was below 40 F. "When arrested by a coarse 

 filter, these Crustacea appeared to the naked eye of different colors, and 

 16 



