CHAPTER XII BATTERY CHARGING DEVICES The automatic plant most desirable--How an automobile lighting and starting system works--How the same results can be achieved in house lighting, by means of automatic devices--Plants without automatic regulation--Care necessary--The use of heating devices on storage battery current--Portable batteries--An electricity "route"--Automobile power for lighting a few lamps 250 ILLUSTRATIONS Even the tiny trout brook becomes a thing of utility as well as of joy _Frontispiece_ Farm labor and materials built this crib and stone dam 17 Measuring a small stream with a weir 23 Efficient modern adaptations of the archaic undershot and overshot water wheels 59 A direct-current dynamo or motor, showing details of construction 92 Details of voltmeter or ammeter 128 Instantaneous photograph of high-pressure water jet being quenched by buckets of a tangential wheel 194 A tangential wheel, and a dynamo keyed to the same shaft--the ideal method for generating electricity 194 A rough-and-ready farm electric plant, supplying two farms with light, heat and power; and a Ward Leonard-type circuit breaker for charging storage batteries 244 INTRODUCTION The sight of a dozen or so fat young horses and mares feeding and frolicking on the wild range of the Southwest would probably inspire the average farmer as an awful example of horsepower running to waste. If, by some miracle, he came on such a sight in his own pastures, he would probably consume much time practising the impossible art of "creasing" the wild creatures with a rifle bullet--after the style of Kit Carson and other free rovers of the old prairies when they were in need of a new mount. He would probably spend uncounted hours behind the barn learning to throw a lariat; and one fine day he would sally forth to capture a horsepower or two--and, once captured, he would use strength and strategy breaking the wild beast to harness. A single horsepower--animal--will do the work of lifting 23,000 pounds one foot in one minute, providing the animal is young, and sound, and is fed 12 quarts of oats and 10 or 15 pounds of hay a day, and is given a chance to rest 16 hours out of 24--providing also it has a dentist to take care of its teeth occasionally, and a blacksmith chiropodist to keep it in shoes. On the hoof, this horsepower is worth about $200--unless the farmer is looking for something fancy in the way of drafters, when he will have to go as high as $400 for a big fellow. And after 10 or 15 years, the farmer would look around for another horse, because an animal grows old.