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Attachments for power-mills for feed-grinder &c., are also 

 supplied by the aeromotor companies. The actual cost of 

 erecting the aeromotor at the Sibpur Experimental farm 

 ( which has an 8 ft. wheel and 40 ft. tower ) was about 

 Rs. 900. 



155. Aeromotors with sails moving in the horizontal 

 plane have been also invented. Rollason's horizontal wind- 

 motor has been actually utilized in working a complete plant 

 of fifty 16 candle-power incandascent lamps, from which it 

 is easy to judge of its capacity for motive power. Messrs. 

 Rollason calculate that with a wind of 16 miles per hour, an 

 8-ft. motor wheel ( horizontal ) generates J horse-power j a 

 lo-ft. wheel i horse-power, a i5-ft. wheel 2j, and a 2O-ft. 

 wheel 5 horse-power. A Freeman's i6-ft. vertical wheel 

 ( which is a power-mill ) generates 5 horse-power under the 

 same conditions as a 2o-ft. horizontal wheel of Messrs. 

 Rollason's. With stronger winds up to 8 horse- power is 

 developed. So this represents the maximum capacity of 

 wind-mills, under ordinary conditions. When a storm is 

 blowing the mill should not be geared at all for work, the 

 vane being disattached from the wheel by pushing the brake 

 up. The vane and the wheel will then both be in the same 

 direction as the wind and little resistance will be offered by 

 either. 



156. Water-power. In utilising water-power initial ex- 

 penditure is the only item worth considering. There is no 

 loss of time in utilising wind and water-power as there is in 

 using steam-power, and there is no expenditure on account 

 of coal and cartage of water. If there is a constant flow of 

 water, it is a more reliable and efficient motor than wind. 

 A high elevation or a precipitate fall is not necessary if the 

 current is sufficiently strong. The current, that is, the speed 

 of water, may be measured by a simple means. Measure a 

 distance of, say, 20 yards, along the centre of the stream or 

 channel intended to be utilised, and let a bit of cork or any kind 



