45° apparatus for teaching Mechanics. 



the loweft fo//.v or thread of the fcrew ; as the arms of the fhift are turned round, the 

 wheel will afceiid, and carry up the weight which is faftened to the lever *. As the fitu- 

 ation of the fcrew prevents the weight from being fufpended exa£lly from the center of 

 the fcrew, proper allowance muft be made for this in eftimating the forte of the fcrew, or 

 deiermining the mechanical advantage gained by the lever : this can be done by meafuring 

 the perpendicular afcent of the weight, which in all cafes is better, and more expeditious, 

 than meafuring the parts of a machine, and eftimating its force by calculation ; becaufe 

 the different diameters of ropes, and other fmall circumftances, are frequently miftaken in 

 eftimates. 



The fpace pafled through by the moving power, and by that which it moves, are infal- 

 lible data for eftimating the powers of engines. Two material fubjedts of experiments yet 

 remain for the Panorganon ; ftiftion, and wheels of carriages. We repeat, that it is not 

 intertded in this, or in any other part of our defign, to write treatifes upon fcience ; but 

 merely to point out methods of initiating young people in the rudiments of knowledge, 

 and of giving them a clear and diftinft view of thofe principles upon which they are 

 founded. No preceptor, who has had experience, will cavil at the fuperficial know- 

 ledge of a boy of twelve orthirteen upon thefe fubje£ts; he will perceive, that the general 

 view, which wewifli to give our pupils of the ufeful arts and fciences, muft certainly tend 

 to form a tafte for literature and inveftigation. The fciolij} has learned only to talk — we 

 with to teach our pupils to think, upon the various objefts of human fpcculation. 



The Panorganon maybe employed in trying the refiftance of air and water; the force 

 of different mufcles; and in a great variety of amufing and ufeful experiments. In aca- 

 demies, and private families, it may be ere£ted in the place allotted for amufement, where 

 it will furnifli entertainment for many a vacant hour. When it has loft its novelty, the 

 (haft may from time to time be taken down, and a fwing may be fufpended in its place. It 

 may be conftrufted at the expence of five or fix pounds : that which ftands before our 

 window was made for lefs than three guineas, as we had many of the materials befide us 

 for other purpofes. 



* In this experiment, the boy (hould pull as near ^s poffible to the fliaft, within a foot of it, for in- 

 ftance, elfe he will have fuch mechanical advantage as cannot be counterbalanced by any weight which the 

 machine would be ftrong enough to bca:'. 



IV. Experiments 



