AMERICAN INSTITUTE. 407 



[London Society of Arts, November 24, 185S.] 

 Mr, r. Joubert read a paper on a method of rendering copper engraved 

 plates capable of producing a greatly increased number of impressions. 

 The valued engravings of the last century, Hogarth, Strange, Heath, and 

 others, were in great demand, and as copper would not supply it, steel 

 plates were substituted for engravings some forty years ago. We now 

 harden the face of copper plate engravings by coating them with a thin film 

 of iron, eft'ected by placing the plate at the negative pole of the galvanic 

 battery, and a plate of iron at the positive polo, and both plates immersed 

 in a proper iron solution — a deposit of iron, bright and perfectly smooth, 

 is thrown upon the copper plate. This coat can be removed and renewed 

 as often as is required. It is said that twelve thousand impressions from 

 one copper plate can be taken. 



The subject of erecting a " a suitable edifice for the American Institute " 

 being called up, 



Mr. Leonard said that his idea of it was one extensive floor, safe for 

 crowds of persons, presenting the whole exhibition at a glance — such a view 

 was always interesting. His long experience in fairs satisfied him that no 

 building for such crowds and such exhibitions should be much elevated. 

 He acted a part in the management of the late Crystal Palace, while it 

 held the World's Fair, as well as that of the American Institute. He has 

 examined the edifices for like purposes in other cities. That in addition to 

 the great works of our people in still life, in the composition of the fair, 

 few were more interesting than the magnificent machinery of our people in 

 full action, from the smallest moving powers to the most massive — from a 

 card-printer to a Hoe's printing press — from a watch movement to the 

 most pov.'erfal steam motor, or perhaps the turning and boring of 30 ton 

 shafts or Dahlgreen cannon of many tons weight. All this demands space 

 and perfect strength, while the spectators in tens of thousands can examine 

 all with as much feeling of safety as if they were in an open garden. 



When this Institute, in its infancy, held a fair in one room in the former 

 Masonic Hall, on Broadway, opposite to the New York Hospital, it re- 

 quired power to put some small machinery in motion, and was actually 

 obliged to hide a stout negro man to turn a crank for a loom weaving 

 woolen cloth — the first power loom ever used for woolen. We have at- 

 tracted, by our fairs, hundreds of thousands of persons to the city, whose 

 money remained for our benefit. This city demands such exhibitions, and 

 to refuse us a place to hold them on, would make the very stones in our 

 streets cry out shame. 



Mr. Sykes thought an entire block would be necessary, with stores, &c., 

 on its exterior to let, while the whole interior could be occupied with the 

 fair. 



Dr. Holton read an extract from the Caen Stone Series, written in 1853, 

 describing a union between the American Institute, Lyceum of Natural 

 History, Historical Society, Observatory, and kindred associations, seek- 

 ing at the present time a permanent depository for their treasures of nature, 



