178 Teaxsactioxs of the Americax Ixstitvte. 



is an exceedingly useful auxiliary in tlie process of lieliogrfipliic 

 engraving ; and it enters more or less into nearly every branch of 

 metallurgic industry. Electrotyped plate for the table has almost 

 wholly superceded, except in the families of the very rich, the use of 

 solid silver ; and this certainly without any diminution of the use- 

 fulness or the beauty of the objects employed. In the Coast Survey 

 Office of the United States, all maps and charts are originally 

 engraved on copper, but these original plates are never used in the 

 ordinary process of printing ; the plates actually used on the press 

 are galvanoplastic copies of the originals, which as they are success- 

 ively worn out can be easily replaced, as the sharpness of the orig- 

 inal engraving is not in the least impaired by the process of copying. 

 The most extraordinary feat in the waj^ of galvanoplastic copy ever 

 produced, was probably that accomplished by the agents of the French 

 government during the first military occupation of Rome. This 

 consisted in making a perfect y«c simile in copper, and in full size, 

 of the great column of Trajan, two hundred feet in height. This 

 copy is now deposited in the palace of the Louvre, divided, from the 

 necessity of the case, intp lengths of some twenty feet each, and is 

 open freely to the inspection of all visitors. 



To resume our enumeration — there again is the manufacture of 

 steel, in which the revolution accomplished within the last thirty 

 years is among the most wonderful recorded in the whole history of 

 industry. There are the telegraph and tlie various forms of tele- 

 graphic apparatus — all of which have been created since 1839. If 

 we turn to the chemical arts, there are the varied and brilliant ani- 

 line dyes, extracted from a substance, least of all promising results 

 so splendid — the tar of the gas house. ' There is the metal, alumi- 

 num, combining the two important properties of incorrosibility and 

 ■extreme lightness, for which the uses will rapidly multiply as the 

 cost of production is diminished, and which has already given us a 

 form of bronze having the beauty of gold and the hardness of steel. 

 Al l these are examples of industrial products or inventions which 

 had no existence in the earlier years of your institution, and which 

 had no part in its earlier exhibitions. 



If again we turn our attention to objects which are not new, there 

 is no reason to doubt that we shall find as much to admire in the 

 improved quality of these things as avc have found already in the 

 novelt}'- of others. It would, indeed, be exceedingly interesting if it 

 were possible, to compare the beautiful carpets I have seen yondes 



