Farwell and Stifler — Common Laboratory Experiments. 537 



2. An Improved Inclined Plane. 



The unsatisfactory results obtained in our laboratory with 

 various inclined planes and friction planes have led to the con- 

 struction of a form of plane which may be of some interest to 

 those who have experienced the same difficulties. 



The chief sources of trouble appeared to be in lack of rigid- 

 ity, uncertainty of angular motion, and lack of fine adjustment. 

 These are all of a mechanical nature, and have been practically 

 eliminated by our mechanician, Mr. Cooey. The plane and 

 its bed are of cast iron and are machined to a satisfactory 



Fig. 3. 



finish. The upper surface of the plane has been carefully 

 planed, and polished to some extent, though not as much as 

 possible. The bed is furnished with levelling screws. The 

 hinge is formed by accurately boring openings in the tabs on 

 the two castings and closing them with drill rod pins. To 

 avoid unnecessary weight, both bed and plane are much thin- 

 ner in the middle than at the edges, the dimensions given 

 in the figure referring to the outside measurements. 



The elevating device is attached to the inside of the base. 

 Its operation may be readily understood by reference to the 

 diagrams. The inside of the base frame is slotted for a short 

 distance near the rear so as to support a rectangular carriage B 

 which is moved forward or backward by means of a screw A 

 which carries a small wheel at its outer end. D is a rod con- 

 necting the carriage B with the short arm of the bent lever C. 

 The end of the long arm of C is in contact with the under 



