ABSTRACT
America claims particular notice by the application of electro-magnetism to the registration of astronomical observations, thus enabling the hand to do the work of the mind. There are many photographic cameras, to the improvement of which much attention is at present being paid in both England and France. There are several exhibitors of air-pumps, who have exercised much ingenuity. There are various machines for standard measures of length exhibited, two of which are extremely beautiful. The Exhibition will make the improvements which have been made in different instruments by various countries known to all; and the means for the acquisition of knowledge, hitherto confined to the few, will, by it, be placed within the grasp of the many.
