SrEClAL REPORT OF MR. HILL, ON MACHINERY. 411
Group thirteen, was divided in the Exhibition catalogues into the following sub-divisions :—
1. Prime movers of all kinds.
2. Machines for transmitting power.
3. Machinery for working various kinds of material, iron and wood-working machinery, and machines and tools for every variety of special work, as spinning, weaving, etc., paper, sugar, ice, etc., etc.
4. Other machinery not included in the above, as blast engine-pumps, fire-engines, etc.
5. Materials and parts of machinery.
6. Railway machinery and apparatus, including locomotives.
7. Mountings, fittings, supplies, etc.
8. Vehicles not connected with rail.
9. Statistics of production, etc.
The writer will not attempt to describe the great mass of exhibits displayed at the Exposition, and included under these various heads. Attention will only be drawn to some of the leading points suggested by their study, and to a few machines which by their novelty or importance would be particularly deserving our notice. The great collection of special machinery in the third department could only be properly presented by specialists in each industry, and the writer, except in the cases of the general iron and wood-working tools, will not undertake to speak of them. Some are noticed by other writers in their special reports ; others belong to industries on which adequate reports could not be obtained.
Beginning with the topic of prime movers, we speak first of boilers. Thirty-five of these were exhibited at Vienna. Those in use, which, contrary to the plan in Paris, were furnished by the various nations, each for their own motive-power, "were placed in detached buildings on the north side of the machinery-hall, and the steam was carried under ground to the various engines which used it. To prevent accidents from explosion, the various boilers were all placed in pits, properly Walled up and roofed over with neat buildings, whose gable- ends towards the machinery-hall were open. A breast-high