Power From The Wind. (pInom A-N ZNGnqEE=IG COREFSON-DEN.) I In view of our diminishing reserves of coal and petroleum, the utilization of wind-power deserves careful attention. The available water power in this country is very limited, and the development of it generally involves so great a capital outlay that the standing charges more than equal the cost. of the coal required to produce the same results by means of gas or steam. MWost of our rlvers traverse more or less fat country through rwhich they flow in a sluggish manner, and in order to obtain the necessary fail for their utilization costly embankments and dams have to be constructed, while even when rivers, such as the Thames and Severn, are already dammed at intervals for purposes of navigation the power thus provided is not always taken advantage of. Wind- power, on the other hand, is almost unlimited, and the capital outlay for its development compares favour- ably with that required for gas or steam. The inter- nittent and varyig results obtained from wind- mills, however, confine their usefulness to industries in which the storage of power can be simply effected, and this feature is always met with in some form or another. Pumping for water supply entails storage in the form of a reservoir to meet the demand when calm weather prevails, while if wind-power be resorted to for drainage a similar purpose is served by the dykes in wlhich the water accumulates until the windmill is able to remove it. As regards the grinding of corn, storage is still in evidence, the steady demand for the produce from the mill being met by accumula- tions of raw and finished material. It is onlv when windmills are used for providing a constant supply of electric current that storage becomes costly and troublesome, and the conditions must be favourable to enable wind to compete successfully with other sources of power in this case. Nearly equal in importance to the question of storage s the cost of attentlance; hence the best results may be looked for from pumping by wind engines, since this work requires practicallv no atten- tion at all. Corn-grindmig demands constant super- vision when the windmill is at work, hut the miller can generally find other duties to fill up his time during calm intervals. The supply of electric current by wind-power must be effected with a minin2imm of atten- tion if the cost is to be kept below that of a gas engine, and in the more recent installations of this nature the apparatus has been made nearly auto- matic. The power of a windmill increases approximately in proportion to the speed of the wind cubed, provided that the revolutions per minute can be allowed to vary in a suitable ratio, and if full advantage is taken of this fact very good results are obtained. But unfortunately It is only when a windmill is used for pumping that its speed can be allowed to increase in proportion to the velocity of the 'wind, and even fcr this purpose means have to be taken to limit the re- volutions per minute during heavy gales. Another feature maldng for efficiency in wind-power pumping installations is that no speed-increaslng gear is re- 9uired, the pump being worked direct from the wind shaft ; moreover, nb provision in the way of extra gear is necessary to allow the mill to move round according to the direction of the wind. Corn- grinding by windmills involves bevel gear to trans- mit the rowver down to the miilstones, and spur gear to drive the stone shafts at the requisite speed. For this purpose the increase of speed is not very great, but since no considerable variation is allowable full advantage cannot be taken of high winds. The losses in the gear for drlving a dynamo from a wind- mill are still greater, because the speed must be enormously increased; on the other band, it Is quite possible to adopt a form of apparatus which will nllow the speed to be varied 3n accordance with the force of the wind. some portion of the extre power developed by strong winds being thereby utEiied. For pumping, oat-crushing, root-cutting, sawing, and siminlar intermittent work about a farm, the wind engine has long since proved its superiority over other forms of power when a favourable exposure is practi- cable, and windmills are being soldiniarge numbers for such duties. Their original purpose of producing flour from wheat has become almost extinct, owing to the improved quality now demanded, steady speed being essential for obtaining the best results. The use of electric motors for driving the odd machinery about a farm is extending, and it seems highly pro- bahle that the current required might be generated by a, windmill and dynamo situated upon adjacent high ground, overhead wires being run to various con- venient points. No battery would be necessary, as such work can be done whenever the wind happens to serve, and the equipment might include a portable motor wvith temporary cables for threshing. It must be admitted that the capital outlay would be consider- able, but this item is balanced by the exceedingly low charges for upkeep and repairs. Much depends upon the natural conditions and the cost of coal or petroleum. A farm situated upon a hill would drive most of its machinery direct without electric trans- mission, the windwill being placed over the grinding shed, whilst the corn stacLks might even be so arranged as to enable threshing to be done directly by wind power. On the other hand, a supply of water would certainly have to be pumped, and the well would pro- bably be situated on lower groumd, the solution being electrical transmission from a dynamo driven by the windmill. The "valley" farm, if wind power is to be used, must either cart the raw material to the wind engine or adopt electric transmission to machines in the farmn buildings. The alternative source of power for the farmer Is a portable oll engine, which has to he hauled about by horses to the points at wrhich its services are required. This method involves a high cost for attendance, as not only has7 the engine to be taken to the work by a man and perhaps two horses, hut a good deal of time is occupied in adjusting the belt and getting the pulleys in line. Then, again, the cost of repairs is quite appreciable, and oil has to be purchased and carted to the engine. In view of these disadvantages, the extra outlay on a windmill with electrical tra ssion would often be justified. The amount of wind power which could be utilized in the manner indicated above is, however, almost negligible as regards any reduction in our national consumption of coal; and before windmills wl seriously compete with gas or steam engines they must demonstrate their capability of providing power regularly for say 10 hoursr a day, or keeping up a con- etant supply. These requirements can only be met by the storage of energy in sufficient quantity to meet the demands for power during calm intervals ; hence the probable duration of the latter is of the utmost importance. The wind velocity recorded at Yar- mouth in 1905, by an instrument mounted at a height of 60ft. from the ground, showed a period of eight days in which the average speed over the 24 hours in each day never reached 10 miles an hour. When, however, the diagrams are examined in detail, it is found that the wind velocity exceeded this figure for several hours out of every 24, and this feature appears to accompany other calm periods during the year in question. Provided that the windmill can be made automati- cally to charge the battery at any time during the day or night, and that a wind of ten miles an hour is sufficient to develop the normal full load, abatterv capable of meeting the demandq for tV:e two heaviest consecutive days in the year wil be found of suffidcent capacity to keep up a constant supply. The normal full load above mentioned should equal in amperes about 1-12th of the batterv capacity in ampere hours, but although the winimill is only rated on this basis, it will be of advantage if the dynamo is capable of developing about twice this output continuously, in addition to a considerable overload for short periods. By these means the high powers given out by the windmill during strong winds can be in some measure taken advantage of. Automatic appliances are now used to cut out the dynamo when the voltage is too low, and to weaken the field as the speed rises beyond a certain point, these controling devices being supple- mented by mechanical means on the windmill for limiting the speed in high winds. With arrange- ments of this kind it appears possible that wind eleetric plant might be successful in considerable powers so long as a battery of sufficient capacity is practicable. Beyond this point stand-by gas plant w%'ould be essential, entailing attendance, but the cost of the latter would be counterbalanced by the saving in capital charges and upk;eep. A sroall battery work- ing through an automatic booster would be necessary but the capacity and cost wrould be smnall in compari- eon with the storage requirements without the stand- by plant. An alternative plant Would consist of a gas or oil engine, dynamo, aad battery; the last would be of the same capacity as for the wind installation, but the dynamo might be considerably reduced in rating. These features being allowed for, the capital outlay will be found about equal in each case, but as regards running expenses a decided advantage. rests with the wind-driven plant, as repairs and attendance cost les and no fuel is requirea. POWEB PROM THE WN.