Independently of the exhibit indicated by its name and character, the Palace of the Liberal Arts encloses one of the great curiosities of the Exhibition of '89; that is the "retrospective history of labor and anthropologic science." "The aim of this exhibit," said M. Jules Simon, in a report which he made as the president of the Superior Commission, June 15, 1888, "is to instruct the public in the history of the processes of manual and mechanical labor, which in the passage of centuries have resulted in the modern industrial utensils used in the arts and trades." This exhibit has a particularly historical and technical character. It is far from excluding objects of art, for in several ages the utensils, those especially which were used in the liberal arts, were veritable jewels, either from their elegance of form, or from the richness of their material, or the grace of their details. We find chefs-d'oeuvre, for instance on a geographical map, on the handle of a chisel, on the barrel of a musket. Our ancestors were not possessed with the same passion for speed and cheapness that possesses us. Industry lost, perhaps, but the arts were the gainers. The aim of the retrospective exhibition is well defined. It is to retrace with broad strokes by means of the reproductions of diagrams and authentic monuments the stages of human genius. To achieve this result it was necessary to associate with the retrospective exhibition of labor that of anthropologic science, in order to show in the outset what man was when he left the hands of nature in the different physical forms of different races. The exhibit of anthropological science and history of labor comprises then five grand divisions—first, anthropologic and ethnographic science; second, the liberal arts; third, arts and trades; fourth, means of transportation; fifth, military arts.
The central nave of the Palace of the Liberal Arts is wholly occupied by this exhibit. Grand porticos and galleries of woodwork with platforms in the lower story, form four grand divisions with interior courts that approach by monumental staircases opening under the dome upon each side of the rotunda, which occupies the centre and shelters the theatrical exhibit. All around the porticos and galleries full panels were reserved upon which M. Charles Touché placed decorative compositions broadly treated in aquarelle illustrating, so to say, the history of labor.
AN INGENIOUS PLAN FOR STRAIGHTENING WALLS.—Yankees, as a rule, are equal to any emergency; what the average Yankee mechanic fails to conjure up at a time when his wits are most needed, leaves very little room for foreign genius to think and work in. Yet it remained for M. Molard, a French architect, to contrive an original and ingenious plan for straightening the walls of the Conservatoire des Arts et Métiers, which threatened an absolute collapse owing to the extreme weight of the roof. A series of strong iron bars were carried across the building from wall to wall, passing through holes in the walls, and were secured by nuts on the outside. In this state they would have been sufficient to have prevented the further separation of the walls by the weight of the roof, but it was desirable to restore the walls to their original state by drawing them together. This was effected in the following manner: Alternate bars were heated by lamps fixed beneath them. They expanded, and consequently the nuts, which were previously in contact with the walls, were no longer so. The nuts were then screwed up so as to be again in close contact with the walls. The lamps were withdrawn and the bars allowed to cool. In cooling they gradually contracted and resumed their former dimensions; consequently the nuts, pressing against the walls, drew them together through a space equal to that through which they had been screwed up. Meanwhile the intermediate bars were heated and expanded, and the nuts screwed up as before. The lamps being again withdrawn, they contracted in cooling, and the walls were further drawn together. This process was continually repeated, until at length the walls were restored to their perpendicular position. The gallery may still be seen with the bars extending across it, and binding together its walls.—Philadelphia Record and Guide.
LOSS OF POWER BY RADIATION OF HEAT.[3]
The Martyrs Column, Naples, Italy.
To him who holds the purse and pays for the coal consumed, it is of importance that between the energy of the burning fuel and the power developed by the engine there should be the least possible loss. Every unit of heat radiated by boiler-pipe, cylinder or heater is absolute loss, and must come out of that purse. In an electrical plant this matter is of great importance. There is less opportunity to have results obscured. There is, proportionally, a large possible loss between the coal on the grate and the far end of the cylinder, and this loss should be reduced to the minimum. Is it not always the best economy to throw away as little as possible, to save from waste all that can be saved? Is not the very reason far being, of the architect, the mechanical engineer, in fact of every man who is paid for his advice and direction, just this: that he shall bring to bear upon the subject, and impart to his client honest knowledge concerning the various matters about which he is consulted? That he shall keep abreast of the tide of discovery and improvement, and that upon these subjects he shall know, not trusting to mere hearsay or to unintelligent prejudice for his impressions.
Some little time since a gentleman from a neighboring city called upon me for information upon the subject of coverings in general and their comparative values. Being an intelligent man he said frankly at the outset that he knew very little on the subject. He had, however, in common with all of us, heard the word "asbestos" used as a shibboleth for years, but he desired definite knowledge, and after he had digested the information he should act on his judgment. I devoted sufficient time to him to put him in possession of the salient points of the subject. His understanding was acute. He left me to seek elsewhere further light upon this matter. After some few days he returned and directed that the magnesia covering be applied to his work. In the course of conversation he remarked that he had received great diversity of advice from those to whom he had gone. One man, who had been years in the business of selling steam plants, told him that the best thing for him to use was hair-felt, even though the steam-pressure might run up to 125 pounds to the inch. Now, as a matter-of-fact, the man who gave that advice simply showed himself an unsafe guide; and from his inability to keep abreast with modern knowledge, that he had no conception of the fire-hazard which his advice was to thrust upon the innocent inquirer, and that his advice was little short of being morally criminal.