1 J IB Asiatic Society. [No. 144. 



inform me so soon as possible, if your arrangement of collections may be so much pro- 

 ceeded, that it should be desirable to you to receive any things from Europe in the 

 way of exchange. 



At the same time I take the confidence to include here some letters and little 

 addresses, expressing my wishes of exchanging Minerals. In the interests of the science 

 1 beg you, Gentlemen, not only to communicate those letters and addresses to such 

 of your honourable members or other scientific Gentlemen, friends to Mineralogy, 

 who you may think able and willing to enter in such a relation of exchange with me, — 

 but also to give their consent such a publication as possible in the scientific world of 

 your country. I should be exceedingly indebted to you for every one communica- 

 tion, which could bring me to the desired relation of exchange, and I believe it advan- 

 tageous to both parties, and to the science in general. 



1 expect your honourable reply, and I have the honour to remain with the greatest 

 consideration and respect, 



Gentlemen, 



Your most obedient servant, 



Dr. Fr. Tamman, Jun. 



Address to Fr. Tamman, jun., Berlin, Prussia, care Mr. H. Pontoppidan, 

 Hamburgh. 



CIRCULAR. 



Berlin, Prussia, July 17, 1843. 



Sir, — In possession of one of the greatest and most beautiful collections of Minerals 

 we have on the Continent, I take the confidence to propose to you an exchange of 

 fine and well cristallized Minerals and Petrifactions from Germany, Sweden, Norway, 

 &c. &c. for such Mineral productions of your country. The conditions which I propose, 

 are the most simple in the world. I make you the first invoice, and after its arrival, you 

 return me in British Minerals, what you may think an equitable and just equivalent. 

 The expences for the transport must pay, who receives the box. 



Being a scholar of celebrated Mr. Mohs, I occupy myself particularly with Cristallo- 

 graphy, and cristallized specimens are, following, particularly desirable and interesting 

 to me. I collect not petrifacts, and occupy myself less with Geology than with Minera- 

 logy ; following I prefer to receive minerals and cristals, also for the sent petrifacts, 

 supposed that you may not have in the last rare and here unknown things. In relation 

 of exchange with a great number of friends of the science I consent to receive a num- 

 ber of specimens of the same sort, which perhaps you may have abundantly, supposed 

 that the sort may be interesting, and the specimens fine. 



On the other side, I give you of the things which I can offer in this moment a 

 Catalogue, and also a list of those specimens of your country, which I desire particular- 

 ly. Remark, that those, which are underlined, are the most desirable. Have you, 

 Sir, some scientific friends, who you may think able and willing to enter in such an 

 exchange with me, then, Sir, I should be highly indebted to you for the communica- 

 tion of their addresses to me, and of the mine, which you find on the end of those lines, 

 to them. 



I expect, Sir, your honourable reply, and I have the honour to remain, Sir, 



Your most obedient servant, 



Dr. Fr. Tamnan, Jun. 



