CONTENTS 



CHAPTER PAGE 



I. The Motor Contest ..... 3 



II. Sources of Power for Plowing . . .12 



III. The Measurement of Power . . .15 



IV. The Horse as a Motor for Plowing . . 24 

 V. The Efficiency of the Horse ... 32 



VI. Essentials of the Draft Horse ... 39 

 VII. The Steam Tractor as a Motor Power for 



Plowing ...... 41 



VIII. Performance of Steam Tractors . . .64 

 IX. Fuel for Steam Tractors .... 71 



X. The Internal-Combustion Tractor . . 74 



XI. Efficiency of Gas Tractors . . .106 



XII. Fuel for Gas Tractors .... 112 



XIII. Early History of the Plow . . . 130 



XIV. The Plow in Great Britain . . 134 

 XV. ^he Plow in America . . . .144 



XVI. Plows for Animal Power . . . .159 



XVII. Plows for Mechanical Power . . .167 



XVIII. l^onditions Affecting the Choice of Plows . 183 



XIX. ^ Mechanical Principles of the Plow . .195 



XX. V \Vhen to Plow, and How Deep . . .199 



XXI. Draft of Plows ...... 206 



XXII. Draft of Other Implements . . .216 



XXIII. The Genesis of Power Plowing . . 222 



