16 



CONTENTS. 



that they were brought to Europe in the 

 time of the Crusades, and that they had 

 long been employed in the Easl, where 

 the scarcity of water precluded the appli- 

 cation of that powerful agent to machinery. 



The wind-mill though a common ma- 

 chine, has some things in it more ingeni- 

 ous than is usually imagined. Add that 

 it is generally allowed to have a degree of 

 perfection, which few of the popular en- 

 gines have attained to, and which the 

 makers are but little aware of: though the 

 aid of mathematics has furnished ample 

 matter for its improvement. 



The vertical wind-mill, which is the 

 kind in most common use, consists of an 

 axis or ?hal't, placed in the direction of 

 the wind, and usually inclining a little 

 upwards from the horizontal line. At one 

 end of this, four long arms or yards are 

 fixed perpendicular to the axis, and cross 

 each otb.er at right angles; into these arms 

 small cross bars are morticed at right an- 



gles, and other long bars are joined to 

 them, which are parallel to the length of 

 the arms, so that the bars intersect each 

 other in the manner of lattice work, and 

 form a surface, on which a cloth can be 

 spread to receive the action of the wind. 

 These are called the sails; they arc in 

 form of a trapezium, and are usually nine 

 yards long and two wide. 



The ciicular motion is produced by the 

 obliquity of the planes of these surfaces, 

 from the plane in which all the four arms 

 are situated ; by these means, when the 

 wind blows in the direction of the axis, it 

 does not impinge upon the sails at right 

 angles to their surfaces, but strikes ob- 

 liquely; hence the effort of the sail to 

 recede from the wind, causes it to turn 

 round with the common axis, and the four 

 sails are all made oblique in the same di- 

 rection, so as to unite their efforts for the 

 common object. 

 1 [Tu be continued.) 



COJTTEJ^^TS ofJ\*o. I. I*ol. J, of OISSERl/*En A* RECORD, 



Title page, 



Sir Humphrey D <vy 's Elcmt- nts of Agricultural Chemistry, 



Iodine in Mineral Waters, 



Patent substitute for leather, 



Cnniifction between Meteorology and Vegetation, 



Tro))ical Nights ■ 



Proportion )f Nitrogen in different kinds of Wheat, 



Culture of Beets in Lonibardy, 



New Process for extracting Sugar from Beets, 



Beet Sugar, 



Lizar's Metliod of Engraving, 



Best drink in Harvest, 



Proper time to cut Timber to prevent Ury-rot, 



Manner of making Indian Ink, 



Note respecting ditto, 



1 some trical mode of Drawing, . . 



(Charcoal Chalks for Drawing, 



Experimental lnf(uiry into the laws of Vital Functions, with Observations, &c. kc. 



Process recommended for the Cure of Cancer, 



Febrifuge, 



Increase of Velocity in Machinery, 



Manner of making Lithographic Pencils • • • •. 



Stereotype Metalograpiiic Printing, 



Sea Batliing — where IJeneficial atul where injurious, 



Imitation of Gold, 



planner of Tempering Steel I' dge Tools, 



The means of ii-moving the effects of the bite of the Achler, 



Itemarks npfin the Smut in Wiieat, 



On the suitable ren>edies for the most prevalent diseases of slieep, 



Manner of taking Impressions from recent Manuscripts, 



Another metliod, 



Manner ot taking Impressions on Paper, from designs made on Stone, 



On tlie Blight in' Wiu.Ht, 



<Jn the Distemper in Dogs, 



On Farm liu Idiiigs, with an account of a new species of Roof, 



On tlie ('hinese method of pro[iagating Fruit Trees by abscission, 



Apparatus f<ir the Decomposition of the Alkalies under Naplitha, 



Process employed in India for false gilding and whitewashing, 



Thenard's and Hlainvilles Lithographic Ink 



Wind-Mill in Meciianics, ^ 



Contents 



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