352 



tion proceeds with the production of acids. The bones of the 

 halibut give to sea-water lime salts, at the expense of a portion 

 of the bone. Abstracting lime from the bone, leaves in excess 

 the phosphoric acid, and the washing away of the soluble salts 

 of lime formed, by rains, adds them to the constituents of sea- 

 water. 



Recurring to the composition of guano-rock, we see that the 

 proportion of organic salts and other organic matter, is much 

 larger than exists in the guano from which it was derived. The 

 physical characters of the rock are modified by the presence of 

 these compounds, but the most remarkable change is that from a 

 granular to a compact solid. This change could be effected by 

 infiltration, as takes place from calcareous waters ; but as the 

 rock guano is above the mass producing the soluble organic 

 salts, it is necessary to consider another condition. 



When water holding saline matter in solution evaporates from 

 the surface of the earth, pure water alone escapes, while the 

 saline and colored organic compounds remain at or near the 

 surface. In accordance with this law, the saline matters which 

 can be dissolved, and the colored matters which can be sus- 

 pended, in water, rise to the surface, and so long as capillarity 

 can act, they are deposited in the porous parts, gradually filling 

 the pores and consolidating the surface. Doubtless, while this 

 process is proceeding, rains carry back a part, which is to be 

 raised anew, until finally the surface-rock, no longer pervious, 

 becomes cemented into the compact state it now presents, by this 

 action of capillarity. 



As the material of the guano-rock has been organized at one 

 time, and may now be considered as mineralized, the specimens 

 present a fine illustration of the action of the minor natural 

 forces in changing the physical conditions of matter, as well as 

 its chemical composition. On the other hand, the putrefaction 

 of fish remains, being often accompanied by the formation of 

 acids, we are able to trace to their sources the organic salts of 

 lime, ^s well as the phosphate of lime, which analyses show to 

 exist in sea-water. 



The Committee to whom the subject of " Encouraging 

 and extending the various New England Fisheries," was 

 some time since referred, reported : — 



