Ch. IV.] OKGANIC REMAINS. 41 



strong solution of sulphate of iron. When they had been thoroughly 

 soaked in the liquid for several days they were dried and exposed to a 

 red-heat until the vegetable matter was burnt up and nothing remained 

 but an oxide of iron, which was found to have taken the form of the 

 deal so exactly that casts even of the dotted vessels peculiar to this fam- 

 ily of plants were distinctly visible under the microscope. 



Another accidental experiment has been recorded by Mr. Pepys in the 

 Geological Transactions.* An earthen pitcher containing several quarts 

 of sulphate of iron had remained undisturbed and unnoticed for about a 

 L rvelvemonth in the laboratory. At the end of this time when the liquor 

 .vas examined an oily appearance was observed on the surface, and a 

 yellowish powder, which pr -^C'l to be sulphur, together with a quantity 

 of small hairs. At the bo' ' :;n -^ere discovered the bones of several mice 

 in a sediment consisting : " '^raall grains of pyrites, others of sulphur, 

 others of crystallized green sulphate of iron, and a black muddy oxide 

 of iron. It was evident that some mice had accidentally been drowned in 

 the fluid, and by the mutual action of the animal matter and the sulphate 

 of iron on each other, the metallic sulphate had been deprived of its ox- 

 ygen ; hence the pyrites and '^ o other compounds were thrown down. 

 Although the mice were not mui^ivdized, or turned into pyrites, the phe- 

 nomenon shows how mineral waters, charged with sulphate of iron, may 

 be deoxydated on coming in contact with animal matter undergoing pu- 

 trefaction, so that atom after atom of pyrites may be precipitated, and 

 ready, under favorable circumstances, to replace the oxygen, hydrogen, 

 and carbon into which the original body would be resolved. 



The late Dr. Turner observes, that when mineral matter is in a 

 " nascent state," that is to say, just liberated from a previous state of 

 chemical combination, it is most ready to unite with other matter, and 

 form a new chemical compound. Probably the particles or atoms just 

 set free are of extreme minuteness, and therefore move more freely, and 

 are more ready to obey any impulse of chemical affinity. Whatever be 

 the cause, it clearly follows, as before stated, that where organic matter 

 newly imbedded in sediment is decomposing, there will chemical changes 

 take place most actively. 



An analysis was lately made of the water which was flowing off" from 

 the rich mud deposited by the Hooghly river in the Delta of the Ganges 

 after the annual inundation. This water was found to be highly charged 

 with carbonic acid gas holding lime in solution.f Now if newly- 

 deposited mud is thus proved to be permeated by mineral matter in a 

 state of solution, it is not difficult to perceive that decomposing organic 

 bodies, naturally imbedded in sediment, may as readily become petrified 

 as the substances artificially immersed by Professor Goppert in various 

 fluid mixtures. 



It is well known that the water of springs, or that which is continually 



* Vol. i. p. 399, first series. 



f Piddington, Asiat, Research, vol. xviii. p. 226, 



