Page:Popular Science Monthly Volume 92.djvu/421

 The Bali-Bearing Creeper

It coasts down plowed ground and crawls along hillsides because of its easy-running qualities

��ANOTHER step forward has been L taken in the reduction of friction and therefore of loss of power, in farm tractors, by means of the introduction of ball-bearing creeper or track-laying units. The use of ball-bearings in creeper units has two great advantages. The first is the saving in power effected by the reduc- tion in friction, as a result of which saving, more of the vehicle-power can be em- ployed for doing useful work in pulling plows or other equipment, instead of being consumed in merely moving the tractor itself. That follows from a test which was made by the University of California and in which a ball-bearing tractor

���actually coasted down plowed ground with a three per cent grade.

The sec- ond advan- tage is that the tractor may work on

��At right: A driving Oil unit, showing the ball bearings, and structural features

��Drivinq-pinion

��Ploughed ground is as nothing to this tractor

��side-hills without clogging or binding the treads. This is due to the semi-spherical shape of the two, joining raceways and the slight circular motion which they permit. In levee or side-hill vineyard work, this type of tractor has given very satisfactory results. Some of the unusual feats it can perform are shown in the illustrations.

Tread sections to prevent balls from coming out

��Tread

���punnp Oil

��Casting telescoped here

��^ao^

��Each of the driving units is controlled by separate clutches, so that the tractor can be turned about in its own length.

���Never mind a little thing like a mud ba1±i. Walk right in, turn around, and walk right out again

��We Are Making Our Own Indigo Now

INDIGO is now being made from coal-tar in this country. At Midland, Michigan, one thousand pounds of twenty per cent paste are produced daily. All the tariff bills of this nation, commencing with the tariff of March 3, 1883, and in- cluding the tariff of October 3, 1913, placed indigo on the free list. Not until September 9, 1916, was a bill passed putting a duty on it. It was the first schedule that braved the anger of the German dye makers.

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