KODAK FINISHING 



We Guarantee to get the best possible results from 



your exposures. Mail orders attended to 



promptly. Catalogue and Price List Free 



The Smith Sporting Goods Company 



TUCSON, ARIZONA 



EFFICIENCY 



The Principles of Scientific Shop Management are Applied by us to the 



Printing Business 



We manufacture this Journal. In addition we produce 25 other scientific and technical 



publications and a large number of books and catalogues. 



All are handled on a definite schtdule maintaining the highest standard of mechanical 



workmanship. 



WAVERLY PRESS 



WILLIAMS & WILKINS COMPANY 2419-2421 York Road, Balrimore, Md., U. S. A. 



AUTOMOBILISTS 



You can eliminate tire troubles by using 

 Woodworth Treads. 



Woodworth Treads are steel studded leather 

 covers held on the tires by a patented coil spring 

 adjustment which keeps them always perfectly 

 tight. 



Woodworth Treads are practically puncture 

 proof, are an excellent anti-skid for wet and 

 muddy streets and they prolong the life of the 

 tires enough to pay more than double their cost. 



If you will try a set of Woodworth Treads, 

 keep track of your tire expense and tire troubles 

 as compared with bare tires it will be worth a 

 great deal to you in your future experience with 

 automobiles. 



Send for free booklet to 



LEATHER TIRE GOODS COMPANY, 



Manufacturers 

 Niagara Falls New York 



