MISCELLANEA ETHNOGRAPHICA. 205 



turning or rolling the beam over on a flat surface until it begins to tilt, the weight 

 of the article is shown by suitable marks on the part of the beam which lies upper- 

 most at that moment. But there is no new thing under the sun, and these devices are 

 not far removed from the ordinary form of letter -balance in which a sliding ring, 

 which acts as the fulcrum, is moved along a graduated rod that has a weight at one 

 end and a clip at the other. 



The pendulum type in its simplest form is shown in fig. 9 in which a bent 

 weighted lever is suspended at its highest point. When an article is placed in the pan, 

 the other weighted end swings upwardly and the pan goes down until there is 

 equilibrium and the weight is then read on a suitably placed scale. The weight of 

 the heavy arm and article are not altered as they swing, but their effective distances 

 increase and* decrease proportionately as shown in full and dotted lines. In other 

 words the lengths of a horizontal line cut by perpendiculars from the fulcrum and 

 two centres of gravity change until AL=WD when L, and D are these cut off lengths. 



The graduations when one size or one position, or when one size plus one 

 position, are variable, are of equal size; but when the ratio of two positions changes, 

 the graduation has to be made on a decremental scale so that the marks are 

 1/2, 1/3, 1/4, 1/5, 1/6, etc., of the length of beam from one end for equal increases of 

 weights. Thus, unless special dispositions of the weight is made by suitably shaping 

 the beam, the graduation marks will be decreased in length in the proportion of 1/6, 

 1/12, 1/20, 1/30, 1/42, etc. As with all the other forms, innumerable variations are 

 possible, and a search through the records of the Patent Office would show some of 

 them ; but to give the results of such a search too many illustrations and too many 

 complicated descriptions would be necessary, and no attempt has been made to follow 

 the lever when it merges into a wheel or pulley, or becomes a spring. 



