74 Medals. 



reciprocal and equal. I have repeatedly shown to my pupils, that a 

 jet of oxygen burns in an atmosphere of hydrogen, as well as a jet of 

 hydrogen similarly situated in oxygen. 



I would recommend that all the bodies comprised in the halogens 

 and amphigene classes of Berzelius, should be placed under one head, 

 to be called the basacigen class ; indicating their common and dis- 

 tinguishing quality agreeably to the premises, of producing both acids 

 and bases. The electronegative compounds of these substances to 

 be called acids, their electropositive compounds, bases, as already 

 suggested.* 



Art. IV. — Miscellaneous Communications from an American JVa- 

 vol officer, travelling in Europe ; forwarded from the Mediterra- 

 nean, May, 1834. 



1. Medals. 



Information for American Colleges. — As numismatics forms a use- 

 ful branch of study, and as in our country, collections of original coinsf 

 are seldom to be procured, and when so, at great expense, I have 

 thought our colleges might be interested by an account of an estab- 

 lishment, which I m€t with in London, a {evf months ago. The en- 

 closed advertisement,! will inform you pretty well of its character. 



* After the preceding letter was ready for the press, the following remark of Ber- 

 zelius attracted my attention, as sanctioning indirectly the definition which I have 

 proposed, page 66. 



Treatise, Vol. 3, page 323, he alleges — " It follows from this that the property of 

 playing the part of an acid, is attached neither to the substance, nor to the manner 

 in which the combination takes place. It only indicates a state contrary to the 

 property of being a base. 



t The writer has himself a cabiuet of coins, and has made numismatics a little the 

 subject of study. 



t J. Doubleday, 32, little Russel st., Museum st. (near the British Museum,) Lond., 

 has on sale, casts in sulphur of nearly all the ancient seals, that have been engraved or 

 described in the Vetusta Monumenta, Jirchaeologia, and other antiquarian and to- 

 pographical works. Great seals of England from Edward Ihe confessor : baronial, 

 conventual, and corporate seals, from the conquest, taken from seals appended ta 

 deeds and charters in the various record depositories in the kingdom, or from original 

 matrixes. Beautiful impressions of that extraordinary seal of Southwick Priory, 

 Hants, described in the Archaeologia, vol. xxiii. A very extensive collection of the 

 most beautiful and rare Greek and Roman coins, in sulphur and white metal. Casts 

 of the rarest English and foreign medals, made to imitate the finest bronze, including 

 the Paris mint series of Buonaparte complete. Impressions from ancient and 

 modern gems, Etruscan paterae, and other antiquities. Great seals from Is. to 2s. 6d. 

 Baronial, &c. 4d. each. Greek and Roman coins, 4d.; paedals, 4d. to Is. each. 



