The furnishing of food supplies has always been a question of great importance to cities, and there are few of the latter, great or small, where the establishment of markets is not the order of the day.
At Paris especially, by reason of the massing of the population, which is annually increasing, the multiplicity of the wants to be satisfied renders the solution of this question more and more difficult. The old markets, some of the types of which still exist in various parts of Paris, were built of masonry and wood. They were massive structures into which the air and light penetrated with difficulty, and which consequently formed a dangerous focus of infection for those who occupied them, and for the inhabitants of the neighboring houses. So the introduction of iron into the construction of markets will bring about a genuine revolution whose influence will soon make itself felt in all branches of the builder's art.
The Central Markets were to have been built of masonry, and the work had even been begun, when, under the pressure of public opinion, the architect, Mr. Baltard, was led to use iron. Evidently, the metal that permits of covering vast spaces with the use of distant bearing points that present a small surface in plan, and leaves between them wide openings that the sun and air can enter in quantity, was the only thing that was capable of giving the solution sought. So it has been said, and rightly, that the Central Markets are, as regards the distribution and rational use of materials, the most beautiful of the structures of modern Paris. This system of construction at once met with great success, and the old markets are everywhere gradually disappearing, in order to give place to the new style of buildings.
Notwithstanding their number, the Parisian markets long ago became insufficient, and wants increased with such rapidity that it became impossible to supply them. The municipal administration was therefore obliged, especially in populous quarters, to tolerate perambulating peddlers, who carried their wares in hand carts. This system has the drawback that it interferes considerably with travel, and especially in streets where the latter is most active. Moreover, the merchants and their goods are exposed to the inclemency of the weather. In other places, where large spaces were utilizable, such as squares and avenues, very light structures, that could be easily put together and taken apart, were erected, and markets were opened in these once or twice a week. This method presents serious advantages. Iron markets, in fact, despite the immense progress that they mark, present disadvantages that are inherent to all stationary structures. It is necessary to erect them in populous centers, where land is consequently of great value; and the structure itself is costly.
The result is that the prime cost is very great, and this forces the city to charge the merchants high rents, and the consumer has to pay for it. With movable markets, on the contrary, the city can utilize large areas of unproductive ground, and find new resources, although renting the stalls at a minimum price. The expense connected with the structure itself is very small. In fact, the distinguishing character of such structures is their portability - so that the same shed can be used in any number of different places.
The principal expense, then, will be for carriage; but it is easy to see that there will always be an economy in their use. This is a fact, moreover, that practice has verified, for it is well known that Paris does not get her expenses back from her stationary markets, while the movable ones yield a revenue.
On another hand, as stationary markets are costly, it results that they cannot be multiplied as much as necessary, and so a portion of the inhabitants are daily submitted to a loss of time in reaching the one nearest them.
Finally, from a hygienic standpoint, movable markets present a very great advantage over stationary ones. The latter, in fact, notwithstanding their large open spaces, never get rid of the vitiated air that they contain, and the bad odors that emanate from them are also a source of annoyance and danger to the neighborhood. In movable ones, on the contrary, when the structure is taken apart, the air, sun, and rain disperse all bad odors, and the place is rendered wholesome in an instant.
We have now demonstrated what great advantages the city of Paris and her population might derive from the establishing of movable markets.
It is easy to see that well established structures of this kind would render great services in small towns also. They might entirely replace stationary iron markets, the high cost of which often causes municipalities to preserve their old, inconvenient, and unhealthy structures. As a general thing, market is held but once or twice a week in small towns. In the interior the structure could be taken apart, and the place rendered free.
The question, then, is to have a system of construction that shall satisfy the different parts of the programme that we have just laid out, that is to say, strength, lightness, rapidity of erection, and ease of carriage. The shelters that are at present employed for movable markets at Paris are very primitive, and are wanting in solidity and convenience. They consist simply of wooden uprights to which are affixed cross-pieces that support an impermeable canvas.
In order to render it possible to extend the system of movable markets, it became necessary to first find and study the proper material.
During the year 1883 the city of Paris resolved to make some experiments, and the Direction of Municipal Affairs commissioned Mr. Andre, director of the Neuilly works, to submit to him a plan for a structure that could be easily taken apart. The plan finally proposed seemed to meet all the requirements of the case, and a group of ten structures was erected. The trial that was made of these proved entirely satisfactory. The city then made concession to the Neuilly company, for six years, of the market in Boulevard Richard-Lenoir, of those of La Reine Park, and of the Madeleine flower markets. A six months' trial has shown the great resistance of the materials that we are about to describe in detail.
The structure is supported by cylindrical hollow iron uprights that are firmly connected with the ground as follows: At the places where they are to be fixed, small catches are inserted in the ground so that their upper surface comes flush therewith. These catches consist of two cast iron sides bolted together, and of a bottom and ends formed of flat iron - the end pieces being bent so as to form cramp irons. Each of the sides is provided internally with a projecting piece, and an inclined plane as a wedge. In case the catch becomes filled with dirt, it can be easily cleaned out with a scraper. The iron upright terminates in a malleable cast iron shoe, which is screwed on to it, and which is provided beneath with a projection in the form of a reversed T, the upper part of the horizontal branches of which is beveled off in a direction opposite that of the inclined planes of the catch. This projection enters through the slit and fits into the two wedges, and a simple blow of a hammer suffices to make the adherence perfect.
Fig. 1. - General View of a Movable Market.
The front and hind uprights differ only in length, and the roof timbers are joined at their upper extremities. The figures so well show how the parts are fitted together as to render an explanation unnecessary.
Fig. 2. - Shoes. Fig. 3. - Mode of Joining the Roof Timbers. Fig. 4. - Iron Support. Fig. 5. - Section of a Shoe Inserted in the Catch. - Fig. 6. - Catches.
The dimensions of these structures vary from 6.5 to 5.75 feet in length by 6.5 in width and 6 in height. The rafters are prolonged so as to project 4.25 feet in front, in order to form a protection for the purchaser. This part of the rafters, as well as the longitudinals, is supported by three curved iron braces, which are put in place as follows: The timbers are provided with a ring fixed by a screw, and one extremity of the brace is inserted into this, while the other is held against the upright by a sliding iron socket. The longitudinal timbers are supported between each two uprights by an iron rod that rests upon a block of stone fixed in the ground.
The front ends of the rafters are connected by a longitudinal, 18 feet in length.
The structure is covered with waterproof canvas held in place by wooden rods, to which it is attached.
Fig. 7. - Waterproof Canvas.
The wood employed is pitch pine.
An entire market of 300 stalls can be put up in three hours by one workman and four assistants. - Le Genie Civil.