Item 19 - Letter from Andrew Bell

3 pp

29 Frederick St., Murrays Lodgings, Edinburgh - The view AB took regarding WW's discussion of the action of the wedge [see AB to WW, 21 Jan. 1839], was a different application of it: 'I am now convinced, from a more careful perusal of your demonstration that it is perfectly correct. There is one point however that I think may be made more clear namely that the reaction of the unmoveable obstacle and other parts must be perpendicular in its direction to that of the resistance'. AB proves this with the aid of a diagram.