mination but individual lighting as well. The general practice in most shops is to use small units and plenty of them. Thirtytwo to sixty-four candle power lamps or other equivalent radiants are suspended over each machine tool where great accuracy of work is not essential, these including such appliances as shapers, planers, emery wheels, arbor presses, drilling machines, etc. On lathes, milling machines or grinders, where accurate cuts must be taken, the individual lamps should be supplemented by arc lights or powerful Tungsten lamp clusters, supported from the ceiling and well shaded to reflect the light where it is needed. One candle power per square foot floor area in addition to the individual lights, which should be at least 50 candle power over each tool designed for accurate work should be allowed in the machine shop.

Where electric current is available the most suitable lamp from the viewpoint of steadiness, quality, and intensity of light is the incandescent filament lamp using the Tungsten alloy illuminating element. The flaming arc is an economical light, but it is far from being steady and its color is such that it is hard to discover fine lines or colors having a bluish tinge. The fluctuation in an arc light and even the clicking of the regulating mechanism may become very annoying when engaged in fine work. Many garage and repair shop proprietors in small towns where there is no central lighting plant find it desirable and economical to generate their own current by any one of the many small individual lighting units sold for this purpose using a gas or gasoline engine as power. The electric current reduces the fire risk and as it is the most convenient form of energy for generating power to operate machine tools, the installation of individual lighting plants is justified by the many advantages accruing from the use of electric current.

Where electricity is not available it is rarely possible to find either coal or water gas such as generated by a public service corporation. In many small, isolated communities it may be necessary to use acetylene gas generated on the premises. Some favor kerosene or gasoline vapor lamps in which incandescent mantles are employed. One popular lamp in the rural sections which burns oil under air pressure producing a Bunsen flame capable of heating the usual incandescent thorium mantle is called the "Washing

ton" lamp and is a very economical method of lighting. It is apparent that any system of illumination that involves the use of a naked flame introduces an item of fire risk that is very undesirable in a building where the fumes of gasoline are present.

Electricity is not only the safest method of lighting but the Tungsten lamp is the nearest to sunlight of the artificial radiants. Where electricity is available it will be poor economy to use other means of lighting, except for general illumination as by groups of incandescent mantle gas lamps. For individual lighting the electrie lamp is the most suitable because it is safe, compact, clean, does not give out much heat, is portable and can be used in any position. There is no other means of artificial lighting that permits one to obtain all of these desirable requirements in combination. Considering the relative cost of the various methods of lighting, the following table, based on the cost per 100 normal candle hours, will prove useful:

The writer has frequently noticed the use of poor droplights in garages which are not only undesirable because of the physical discomfort entailed by the action of the electric current upon the human system, but also because of the liability of fire. The wire and sockets of these lamps are subjected to very severe treatment and they soon cause trouble where a cheap equipment has been provided, because the insulation of the wire deteriorates and will cause a short circuit whenever it comes in contact with the metal part of the frame or of the various parts of the human system which will provide a path to the ground for the current. Where a current of 110 volts is used, there is no danger of severe or permanent injuries because of contact with such a "live wire," but the sensation is decidedly unpleasant, to say the least. Cases have

been observed by the writer where a fire has been caused because

One case in particular has because he was in a pit

of such defective insulation of the wire. been distinctly impressed on his mind beneath a car at the time of the fire. A helper was washing the mechanism with gasoline, preparatory to an overhauling, and plenty of vapor filled the air. A partly bare spot on one of the wires became crossed with the frame work of the car and the bril liant spark resulting ignited the gasoline immediately. The car and pit were in flames and had it not been for the presence of mind of another mechanic with a chemical extinguisher in dealing with the blaze before it assumed dangerous proportions, the results might have been more serious.

In figuring on a droplight equipment, the best material should be obtained. It is a "penny wise, pound foolish" policy to use materials for which the only recommendation is cheapness. The wire should be provided with a very heavy insulation, and need not be very flexible. Beware of lamp cord, as it is of no value for use under severe conditions. The best and heaviest sockets should be used. The writer would advise the use of some that had either a very heavy porcelain or hard rubber insulation around them. Then comes the choice of proper cages or shields and handles. There are cages now marketed that are of heavy construction, the wire of which they are composed being nearly an eighth of an inch in diameter. These will prove to be the cheapest in the end. In assembling, it will be found best to wind plenty of electrical tape around the wires for the entire length of the drop. This not only serves as an additional insulator, but takes much of the wear that would otherwise come upon the insulation of the wire proper, and it may be easily renewed when it shows signs of wear. It will be found well to solder all the connections at the socket and rosette, as there is nothing more disconcerting, when a difficult or tedious job of fitting or adjusting is being performed, than to have a "winking" light to work with, which is liable to fail at the time it is needed most.

Heating and Ventilation.-It is very important that the workrooms should be kept at comfortable temperature during cold. weather. About 75 degrees Fahrenheit is usually considered correct,

though it may be lower than this. if the men are engaged in active labor. In the machine shop where men must stand quiet much of the time, the temperature should be higher than in the erecting room, where they are constantly moving around and handling parts, this tending to keep the blood in circulation. It is a mistaken idea on the part of some shop managers that the men must be half frozen so they will exert themselves more than if conditions were more favorable to comfort.

This is true if the temperature is much too high, but there is little danger of this happening in a large shop having considerable metal to absorb heat, and where the doors are opened to admit cars many times each day. A man cannot work with any degree of accuracy if his fingers are numb. When shops are cold, the operatives compensate for this by wearing heavier extra clothing that hampers their movements appreciably. What is gained in fuel is lost in labor, to say nothing of the effect unfavorable conditions have on the dispositions of the workers.

Of the methods of heating in vogue, the writer unhesitatingly recommends steam or hot water, in connection with judiciously placed radiators and pipes. The amount of radiator surface needed should be computed very accurately, and can only be determined by taking into account the character of the walls, number of windows, cubical contents of the rooms to be heated, the facilities for ventilation, the number and size of doorways and many other conditions best considered by a competent heating and ventilating engineer. The steam or hot water boiler has the advantage of furnishing warm water at all times for washing purposes, and as the radiators may be shut off if too warm, the temperature can be regulated to suit requirements and to secure economical and efficient heating from the fuel burned.

The problem of ventilation is one that is of importance, though its character depends upon the type and construction of the buildings used. Repair shops are usually of large size, and have large space in proportion to the number of workmen employed. In many cases of ground floor shops, this ratio is so large that no special provision need be made, the air being changed often enough to answer all practical needs, as the main entrance is opened and

closed. With a number of upper floors, conditions are different and in such cases every endeavor should be made to renew at least one-tenth of the total contents every hour. In paint shops, smith, and testing or adjusting rooms where noxious fumes may be present, and in small rooms where the number of workmen is greatly in excess of the air space available, no less than half the contents should be renewed hourly. The suggestions for building, heating, lighting and ventilation apply to all shops.

Building Arrangement.-As an example of the amount of space allowed in a building devoted to both a garage and repair business

the floor plans of a garage located in a city of forty thousand inhabitants is presented at Fig. 1. This building has a frontage of 74 feet and is 150 feet deep. The front faces a main street and is occupied by a sales room 30 feet square in one corner, and a main office of the same size in the other corner. The sales room has an attractive show window across the entire front, and the other departments are also liberally provided with windows. One side of the plant faces an alley extending the entire distance, and there is also an alley to the rear. This offers the important advantage of providing a situation on what is practically three well paved streets. The alley to the north is practically exclusive and affords the company a chance to store many cars during the day and at the same time leaves plenty of room for the vehicles to move