Fig. 1-Pierce-Arrow limousine of artistic design with electric lighting on the same basis

MERIT,

like the mill of the gods, is sure, but, unlike the great contrivance, it is not, of necessity, slow.

This same merit, as it resides in electric lighting as applied to automobiles, seems to have copied the first characteristic of the mills of the gods, for its development has not maintained pace with the wellauthenticated qualities

of

electric lighting as it is generally applied. The retarded growth of this branch of the industry was not due, at any time, to the absence of desirable qualities in electric light, nor can it be conclusively shown that the discovery of the tungsten lamp is to account for the present activity.

At all events, electric lighting to all appearances is now with us to stay. Tungsten lamps will have an important part, storage batteries will also be in proper presence, but it is in the source of electricity that the present activity is centered.

IMPROVEMENTS MADE IN METHODS OF DRIVING DYNAMOS Dynamos, as they are used in conjunction with storage batteries (if they have to do charging work), are as a rule shunt wound, meaning that the coils of wire (insulated), which are wound around the fields for the purpose of exciting them, are in parallel with the armature windings, and this parallel relation has, among other advantages, the property of fixing the rotation of the armature in one direction only, whether or not current is entering the dynamo (thus making it a motor), or leaving the same, as when the machine is performing its proper function as a dynamo electric machine.

As a shunt wound machine, if the speed and load is constant, the voltage at the brush terminals will be constant also; if the speed changes, however, the voltage will change also, and if the load changes, so will the voltage, due to what is designated as armature "drop," which is due to I'R losses, for the most part, and partly to heat increase, due to increasing load.

Constant Speed Required in Lighting-If lighting is to be done direct from a shunt wound dynamo it is necessary to run the same at a constant speed, and if the load changes, then the resistance, as measured in ohms, of the field, must be adjusted to suit the altered conditions. A compound wound dynamo could

be used (is used in general lighting work) were the speed constant, and with changing loads; this type of winding differs from shunt windings, due to the presence of a second winding on the fields, which supplementary winding is in series with the armature, so that the output of the armature passes around the fields, and they are strengthened in proportion as the armature reaction tends to weaken them. Moreover, I'R drop, in the armature as well as in the series winding of the compounded field, is compensated for, in fine, by over-compounding, which is but a matter of adding a few extra series turns to the field windings. It is possible to compensate also for line losses outside.

All these devices so well known to the electrical engineer are put to naught by the changing speed which obtains in a gasoline motor as it is used for its conventional purpose, and, to add to the confusion, the motor is likely to be stopped betimes, perhaps to make an adjustment, perchance by night, and lights will then be in excellent demand. A tail light, for illustration, should not be allowed to go out, especially when a car is standing still by the roadside on a dark night, and electric lighting, to be a good success, must be capable of doing its work at all times.

Under plain conditions, then, electric lighting direct from a dynamo cannot be done if the power is taken (to drive the dynamc) from the motor which is placed to propel the automobile, for the very simple reason, as before intimated, that the motor is required to run at a variable speed, and the dynamo requires a constant speed. True, there is such a scheme as a "differential compounding," it having the facility, within limits, of rendering the characteristic of the dynamo that of a constant voltage machine under a variable condition of speed. Unfortunately, as it seems, the range of this type of machine is very limited, and it will be remembered that automobile motors change in speed over a broad range; possibly as much as 10:1..

Obviously it would be an extremely difficult task to so design a dynamo that the differential compounding would work satisfactorily under such wide conditions of speed change, nor has any designer ever succeeded in accomplishing this to extent, although, in connection with wind-motors (which run at a variable speed), some success was attained, and for a time it looked as if the task might be fulfilled within certain limits.

Special Forms of Windings Abandoned-The struggles for success through special windings on the dynamos used were long ago abandoned, and for a time it looked as if electric lighting would have to be accomplished through the use of storage batteries unaided by any automatic charging means at hand, which idea, from evidences afforded, seems not to have appealed to autoists, and as a result acetylene lighting was relied upon for the most part. The storage battery unaided, as will be readily appreciated, would have to be of large capacity, or it would be necessary to remove and recharge the same at frequent intervals. This might not be a task of great difficulty were all cars maintained in garages equipped for the work of charging storage batteries, but such is not the case, and, to care for the great majority of automobiles, it has been necessary to fit out with acetylene lighting equipment.

What This System Comprises-Referring to (A) Fig. 2, and to C in the figure, which is a camera, it will be noted that the same is focused on a dynamo D in the figure, and the photograph was taken utilizing the actinic rays, which emanated from the searchlight L just below and to one side of the camera. This illustration indicates that the light is of high intensity, and the

mate the conditions which exist when the lighting dynamo is connected with a gasoline motor as it is used on an automobile. This is done with a view of having the lighting dynamo run at a constant speed, notwithstanding speed variations over a wide range of the automobile motor.

In order to indicate the compactness of the lighting dynamo, B, Fig. 2, is offered in which D is the dynamo, showing the exterior, and how thoroughly it is enclosed, while B is the belt running over a pulley, which also connects over a driving pulley, placed at some convenient point on a driving member of the automobile motor. The power which comes from the automobile motor is subject to wide speed variations, and these variations are transmitted along the belt B, thence to the dynamo pulley and shaft which protrude out through the shell D of the dynamo.

In order to appreciate the operation of the dynamo, it will be necessary to examine the interior, for which purpose (C) Fig. 2 is presented, in which Cr is the base half of the protecting shell, C2 is the detachable half of the same, D presents the dynamo, which connects its armature shaft with the shaft protruding through the case to the pulley, over which the belt B runs. In order to be able to vary the speed of the driving member (the automobile motor) without suffering speed changes of the armature of the dynamo D, a governor G, under the influence of centrifugal force modified by the pressure of the spring S, is then utilized to excellent advantage.

The speed changes, or rather a constant speed of the dynamo armature results from slipping on the clutch faces, F, by variations in pressure on the clutch members C4, brought about through movement of the clutch members C3, under the influence of the centrifugal (weighted) governor G, in view of the action of the spring S. The facing F, is asbestos fabric, and the area of the transmitting surface is so regulated that the speed of the dynamo is maintained at 1,200 revolutions, per minute, irrespective of speed changes within all possible limits of automobiles under road conditions of performance.

The pressure of the transmitting faces of the friction members is but slight, it being the case that the output of the dynamo is 60 watts, which is not so very great, in view of the fact that there are 746 watts in one horsepower. It required a good deal of experimenting to arrive at the correct proportions of the governor weights G, and the proper resistance offered by the opposing spring S. The performance will be obvious from what has been said, considering the clearness of the view C, Fig. 2. It simply follows that one of the clutch members is sleeved, which permits axlewise motion, but the load on the dynamo being nearly constant, in view of the use of a storage battery, permits of designing the governor so that the slippage on the disc faces will be in conformity with the requirements.

A SPECIAL EXIDE BATTERY IS USED Referring to (D) Fig. 2, GI is the dynamo, looking at the pulley end I represents the measuring instrument which is used to ascertain the potential difference in volts across the terminals of the battery and the same instrument, by suitably manipulating, tells the output of the dynamo or battery in amperes. battery is shown as B1, there being three cells within a suitably contrived hard-wood case.

The

The battery has been especially designed with a view to compactness, relatively light weight, and high watt efficiency. The life is guaranteed for three years under the conditions of operation as fixed in this system. This long life comes primarily through the adaptation of a special and particularly well-built battery, but the fact that it is "floated" on the circuit influences the life situation very materially.

This system of lighting affords the widest range of service, eliminates all other forms of illumination when it is used, because the battery has ample capacity to furnish current to tungsten lamps for head and side lights, as well as a tail lamp, for several hours, if the occasion requires, so that if the automobile motor is shut down for any reason, the lighting goes on without diminution of intensity, which condition would obtain for many hours, eve ven under the most unfavorable conditions.

ABRICATED materials differ from castings in important par

FAB

ticulars, and while quality of material, that is to say, its chemical composition, is important, even so the extent of fabrication must be taken note of when an attempt is made to take an inventory of quality.

The difference between fabricated steel and steel castings is represented by the amount of work done upon the castings in rolling or forging. Direct steel castings are made by charging crucible pots, or Bessemer furnaces, and when the charge is brought up to the proper heat it is first poured into ladles and then transferred to moulds, the moulds being substantially the same as those used in gray iron foundries.

In the production of fabricated steel the ingots are first produced and they, after being suitably manipulated, are rolled or forged into the desired shapes. It will not be the purpose here to delve into the processes employed in the production of steel, but the above will be enough to show that, as before stated, the difference between a casting and fabricated steel is represented in the amount of work done upon the steel after casting.

If, in working or fabricating steel, it may be improved, which is true, it follows that shapes, as they are employed for different purposes, will have different qualities. This point is adequately brought out in connection with T-rails. When these were of light weight, varying from 40 to 60 pounds per yard, photo-micrograms showed a certain structural condition, which indicated the excellence of kinetic qualities, and the rails proved to be of great longevity in service. As rails were increased in weight, breakages were more frequently noted, and to-day, with rails ranging from 90 to 110 pounds per yard in weight, this question of breakage assumes the proportions of a paramount issue.

It is claimed by the steel makers that there was no substantial difference in the quality of material used, and nearly all rails were produced by the Bessemer process. The differences were directly traced to ills of fabrication, it being true that the heavier weight rails are not subjected to the same amount of work as

Fig. 2-Rear suspension of Pierce-Arrow cars with 3-4 elliptic scroll springs, flush with the side bars

Taking (A), which is a carbon content, Harboard, after making many experiments, proved conclusively that the shock-resisting qualities decreased with increasing carbon. As to (B), which refers to the carbon condition, there is everything to be gained by resolving the same into the best form, considering the service to be rendered, so that heat treatment becomes of the first importance. (C) considering metalloids, as sulphur and phosphorus, they must be very closely held, particularly in flat steel, and it would not be too much to expect that these elements will come within 0.030, but this must not be construed as a license to reduce metalloids by the utilization of a basic process. Harboard showed, among other things, that steel by the basic process, will not sustain under shock condition to nearly the same extent as will acid steel. Taking the metalloids by chemical analysis then, is not conclusive evidence of quality from this point of view, because the metalloids may be the same in inferior as in superior steel, depending only upon the process employed. (D) refers to manganese and silicon, assuming that copper and arsenic are but a mere trace.

The manganese and silicon contents will differ from the respective products, partly due to process, and, to some extent, with carbon, presence of metalloids, and alloy in elements. It will not be feasible then to discuss the presence of these elements more than to point out that they are suitably regulated under the several conditions of manufacture.

ALLOY STEEL LOW IN CARBON

The presence of chromium nickel, vanadium, tungsten, or other alloying elements, does not seem to alter the main fact, i. e., that carbon must be closely held. Experience in connection with the utilization of alloy steel is relatively limited, and the automobile has been at the bottom of this activity, more perhaps than the influence of any other art, not forgetting that armor plate and projectiles were previously (and are now) alloy steel products. There is a considerable difference between the alloy structural steel as used in automobiles and the material which obtains in the production of armor plate and projectiles.

The very difference between the composition of a projectile