Mr. Smith's Works on Fossil Shells. 71 



frequently with the production of light. Acids render the oxy- 

 genated water more permanent. Gold, finely divided, acts with 

 extreme force on pure oxygenated water, but has no action on 

 that containing a little sulphuric acid. 



MR. WILLIAM smith's WORKS ON FOSSIL SHELLS. 



To Mr. Tilloch, 



Plastow, July 18, 1819. 



Sir, — Having been induced from what I had repeatedly read 

 in your very useful Magazine, concerning Mr. William Smith's 

 ingenious and practical investigations of the British strata, and in 

 commendation of his intended works on Fossil Shells, to become 

 a subscriber to two of them, which were a long time ago begun 

 to be published in numbers ; I shall offer no apology for re- 

 questing permission to address Mr. Smith, through your pages, 

 in order to complain of the slow progress, and apparently unrea- 

 sonable delay, which seems to attend the proceedings with regard 

 to these works. Tiie first of these, "Strata identified by organized 

 Fossils," was begun to be published in June 1816, and was pro- 

 mised to be continued monthly, until it was completed in seven 

 numbers; yet it was only during the last month that the fourth 

 number therebf made its appearance. When does Mr. Smith 

 intend to fulfil his engagements, with regard to the completion of 

 this work ? 



The second of these works, " Stratigraphical System of orga- 

 nized Fossils," was proposed to be completed by Mr. Smith in 

 two parts; the first of which was published in 1817, and yet the 

 second and concluding part has not yet been published. When is 

 this to take place ? 



I make these remarks, and put these questions, from no pre- 

 judice or ill will towards Mr. Smith : on the contrary, I highly 

 value his services in the cause of practical and useful geology, 

 and will, on the completion of these two works within a reason- 

 able time, do all I can to extend the sale of them. amongst my 

 acquaintances. 1 am, &c. 



A Subscriber. 



P.S. Myself and some of my friends made application at the 

 British Museum, wishing to examine the geological collection of 

 fossil shells, corals, &c. which Mr. Smith had deposited there, and 

 had in part described in his Strat. Syst., but were told it was not 

 in order, and could not be seen. Will Mr. Smith have the good- 

 ness, if he can. or some one else, to inform the scientific public, 

 through your pages, whether this impediment to the spread of 

 a practically useful species of knowledge has since been removed, 

 and is i):\tSmilliian collection now accessible to the British public ? 



E 4 , LITHIA. 



