•J2 On thi polytypic Art. 



compofed, I took their impreflion in fine plaifter, mixed with charcoal-duft* ; this moul3 

 enabled me to caft a number of copies of the four lines which I had compofed. I foon per- 

 ceived that the firft and laft letter of each line loft its pofition by finking further back than 

 the face of the other letters. It was eafy for me to obviate this defed, by phcing a fmall 

 metallic fupport at a certain diftance from the beginning and end of each line, to prevent the 

 finking of the letters. It is fcarcely necefiary to remark, that the mould ought to be very dry, 

 and that a flight preflureupon the metal while in the half fluid fiiate, is ufeful to obtain a good 

 plate : feven or eight of thefe are required to form a page in oftavo. I can take upon me to 

 afiert, that this procefs is neither tedious nor embarraffing, and it has the convenience of in- 

 cluding the power of making corredions and additions. 



This, in fhort, is the account I have to give of my enquiries into the typographic art. 

 !Reth, formeily director of the fabrication of aflignats, is better acquainted than any other perfon 

 ■with what has fince been done for the improvement of this important art. I have but a few 

 words to add. In my eflay on ancient and modern coins, I defcribed a method of imitating 

 ancient and modern coins in bell-metal, by the polytypic art. For this purpofe I place in a 

 cavity in an anvil the pieceof bronze heated to a proper degree, to render it foft : the ufe of 

 the cavity is to enable the metal to fuftain the aftion of that preflure which it is to receive 

 from the fcrew or ram at the inftant the medallion is applied to it, which is intended to give its 

 hollow impreflion. If the metal be heated to a proper degree of foftnefs, the original will 

 not be in the leaft altered, whether it be of gold, filver, or copper ; but it is requifite that the 

 jiiece fhouldnot be fufFered to become hard by cooling, nor the medallion itfelf to remain in 

 contiSi with it a fufEcient time to alter its own temperature. The fuccefs of this procefs 

 depends, therefore, on the quicknefs of the operation, and the praftical knowledge of the 

 degree of heat which the objefl: of the imprefiion can bear to foften it without injuring it in 

 other refpedls: it is neceflary to faften the medal to the face of the fcrew or ram, in order 

 iJiat it may not touch the heated metal but at the moment of its fall. 



Two IHver medals ftruck under the magiftrature of Titus Cavifius, Triumvir, Monetariusi 

 which exhibit the inftruments ufed at Rome for coining, fuggefted to me the notion of th6 

 procefs I have been defcribing. There are two dies, one fuperior and the other inferior ; the 

 lower die is fupported on an anvil, befide which lie a hammer and pair of tongs. The form of 

 the tongs leave no doubt refpefting the ufe to which they were applied ; they ferve to place 

 the blanks or pieces of metal of the legal weight and finenefs between the two dies, and 

 thefe blanks being fufficiently heated, could, by a fingle ftroke of the hammer, receive both 

 impreflions. By this defign the ancient art of polytypage is difplayed. The two Roman 

 medals which bear for their defign, the Dies, the Pincers, the Anvil, and the Hammer, were 

 ftruck at Rome three hundred years before the Chriftian era, at the epocha of the war with 

 the Tarentines. Andrew MorelL in his work upon the medals of the Roman Families, 

 •expreffes himfelf as follows: 



** The material ufed by the celibratdd Taffie, in a fimibr proeefs of extreme delicacy, was a mixture of 

 Sulphate of lirae (plaifter of Paris) and tripoli. See PhiloC Journal, II. 63.— N. 



