KURAL ECONOMICS. 91 



Plowing by electricity at Dahlwitz ( MasrJiinrn Ztf/.. '/ (100C). Xo. 12. pp- 

 /.?//, l.l'). pfiK. 2). — The :ii)i);u-atiis in use here consists of a fiiing plow which is 

 alternately moved back and forth across the field between two " anchor wagons." 

 By this apparatus about 2J acres per hour are plowed, and the cost, taking into 

 account all oi)erating expenses and interest on cost of e(iuipnient, including power 

 ])lant, amounts to .$(t.<;4 per acre. While it is claimed that the use of the appa- 

 ratus has ]iroven i)rofitable in this case, it is pointed out that this would not in 

 general be irue except prdbably in those cases where the electric plant could be 

 operated continuously throughout the year, the power generated being i)ut to 

 other profitable uses when not used for plowing. 



The windmill in agriculture, C. E. LAWFoitn ( I'/r. .Jour. Cape Good Hope, 

 28 {1906), Xo. 2. pp. 2011-20.'), figs. 6').— After calling attention to the defects in 

 the mills at present being employed in South Africa and elsewhere, the writer 

 urges the following imi»rovements : More rigid and stronger frames, i)rovided 

 with good ladders and large roomy platforms surrounded b.v railings; a tower 

 cai» provided with large rings and burnished-steel balls; a gear head with easily 

 "get-at-able" bearings and a band brake capable of holding the wheel in the 

 highest winds with a minimum power. To increase the efficiency of the mechan- 

 ism the writer recommends roller bearings in the gear head and a mangle motion 

 in substitution for the usual crank and pitman arrangement. He advises the 

 use of two pump.s — one for light breezes and the other for combination with the 

 first in the case of heavy winds. As to oiling devices, be thinks the endless 

 chain or ring oiler the best for solid bearings, and syphon cups with compound, 

 soft-iron wire wicks the best for roller bearings. The writer thinks that " power 

 mills" have certain essential advantages over the usual form, particularly in 

 the efficiency with which the power is transmitted from the wheel to the pump. 



The utilization of solar heat for industrial purposes by means of a new 

 plane-mirror reflector, C. Guntner (.S'c/. Amer. Sup., 61 (1906), Xo. 1586, pp. 

 2'>'iO'.>~2-')-'il2. fii/s. ()■). — This is a description of a new form of reflector devised 

 by the author, which has certain features radically different from the conical- 

 shaped reflectors of other inventors. His device consists of a series of plane 

 mirrors an-anged in a horizontal position and suppoi'ted by a peculiar link work 

 whicli is moved to conform to the position of the sun, and which maintains the 

 niirmrs in such ]Kisition that the sun's rays are projected upon a long cylin- 

 drical boiler. The latter lies above the mirrors in a horizontal position, with its 

 axis in a north and south direction. The mechanism is such that the mirrors 

 can be turned completely over about their axes as a protection in case of hail- 

 storms. From exi)eriments it was found that a reflector with a surface of 1.000 

 s((. ft. delivered in 12 hours an amount of energy equal to that generated by the 

 consumption of 4,400 lbs. of hard coal, this being in European latitudes. The 

 inventor estimates that the reflectors can be built at an expense of about $2 per 

 square ,vard of surface, and predicts that because of its simplicity, cheapness, 

 and effectiveness it will he useful as an aid to ]inmping operations in arid 

 regions and for other uses in localities where fuel is scarce and sunshine 

 abundant. 



Tests of the relative value of crude oil (Beaumont, Texas), kerosene, and 

 gasoline (Xeir M<:iiro Sid. Rpf. 190 ',, pp. 2'.>-.U\. 



RURAL ECONOMICS. 



Rural economy. O. X. Lau.man (Coniell Couutnjiiiau. .? (1906). Xo. 9. pp. 

 211, 212). — In this article rural economy is tentatively outlined as "that Held 

 of knowledge dealing with the facts, deductions, and theories concerning the 



