There has been considerable difference of opinion as regards the comparative efficiency of chain drive and belt drive. The consensus of opinion, however, seems to favor the chain drive, as evidenced by its use on most of the leading makes of present-day machines. Some of the light-weight models are using belt drive, but chain drive is generally conceded to be superior. In the early days of motorcycling, belt drive was rather generally used, but the heavy duty required soon brought about the change to present usage. Motorcycle manufacture is today carried on in some of the largest and most up-to-date manufactories that can be found in the United States. The oldest and the largest factory devoted to motorcycle manufacture is said to be that which has been built up under the direction of the Springfield manufacturer, the man who first saw the great commercial possibilities in the development of the motorcycle for pleasure and business purposes. His company had a capitalization of $12,500,000 in 1916. Some 2,400 skilled workmen were employed in its two big Springfield plants. Its output, said to be the largest in the industry, is over 25,000 machines per year. Numerous models meeting varying requirements are produced. Soon after the first practicable motorcycle appeared in 1902 there arose a demand for a contrivance that would accommodate an additional passenger. Consequently, there was produced an attachment called a tri-car. This was mounted on two pneumatic-tired wheels which were fitted to the front fork together with necessary steering devices. Later it was found that the passenger conveyance could better be carried at the side mounted upon a springed chassis which was supported by a third wheel. That form was thereupon generally adopted, and remains today the general practice in the manufacture of motorcycle side-cars, as they are called. Naturally enough, interest in motorcycles was quickly directed toward their application to commercial uses, and to that end there were produced numerous styles of side vans and parcel carriers intended for parcel delivery. The use of the motorcycle for commercial purposes was for a time overshadowed by the abnormally rapid development of the automobile, but the factor of upkeep and operation costs of an automobile is bringing the motorcycle into prominence now. In this respect the motorcycle is said to have the advantage overwhelmingly. The tendency, however, among business houses is to investigate their individual requirements for delivery service and determine to what purposes either form of motor vehicle is best adapted. For light parcel system there is said to be no form of delivery that excels the motorcycle in speed and efficiency and nothing with operation costs so low. The commercial motorcycle is said to be gaining widespread favor, and therein lies its greatest future.