The American machinery, which occupies a position between Norway and England, is creditable in kind and quality, but fails very far in giving a correct idea of the multiplicity of our industries. Almost the only evidence of our textile manufactures are two of Tilt's Jacquard silk-weaving looms. The telephones of Edison and Gray excite unremitting astonishment and admiration, and have both received the highest possible awards. Our wood-working is practically shown in a large variety by Fay & Co. of Cincinnati, and one or two other special machines by other makers. The Wheelock engine, which drives all the machinery in our section of the main building, has very properly been awarded a grand prize. It is all that can be desired in an engine, and has a singular simplicity of construction, with few working parts. It is the same which drove the machinery in the Agricultural Building at the Centennial. The steam is admitted and exhausted by a valve at each end of the cylinder placed directly below the port. The cut-off valve is behind the main valve: the mechanism for operating the valves is on the outside of the steam-chest, and easily accessible. The valves and seats are made tapering in their general diameter, and the pressure of steam comes on one side, also acting to keep the collar in contact with the sleeve. [Illustration: TWEDDELL'S HYDRAULIC RIVETING-MACHINE.] The Waltham Watch Company is considered by some of the most influential European journals as the most important in the American section on account of the revolution it is making in that important industry. When the Swiss commissioner went home from the Centennial he published a letter fairly throwing up the sponge, and when the company's exhibit appeared for the first time in Europe at an international exposition it was regarded as carrying the war into Africa. The American system of making by machinery all the parts of an article--say, of a watch--of a given grade by means of gauges and templets, so that the parts may be "assembled," and of such singular exactitude in their making that any part may be replaced by the corresponding piece of any other watch of the same grade, has in this manufactory attained its highest results, greatest precision and most perfect illustration. The whole collection of watches was sold within a few weeks after the opening. The latest improvements in the balance to secure perfect isochronism under varying conditions of temperature would delight the soul of Harrison, who worked from 1728 to 1761 on the problem of a compensator for the changes of rate due to the expansion and contraction of the metal, and received the reward of twenty thousand pounds sterling offered by the Board of Longitude.