176 



NATURE 



{June 2i, 1888 



to overcome the weight of all the cards, and this heavy end 

 of T lies on the base-board S. When the heavy end of T is 

 lifted, as in Fig. 5, its front-bar is of course depressed, and 

 the cards being individually acted on by their own weights 

 are free to descend with the cross-bar unless they are other- 

 wise prevented. The lower edge of each card is variously 

 notched to indicate the measures of the person it repre- 

 sents. Only four notches are shown in the figure, but six 

 could easily be employed in a card of eight or nine 

 inches long, allowing compartments of 1 inch in length, to 

 each of six different measures. The position of the notch 

 in the compartment allotted to it, indicates the correspond- 



ing measure according to a suitable scale. When the 

 notch is in the middle of a compartment, it means that 

 the measure is of mediocre amount ; when at one end of 

 it, the measure is of some specified large value or of any 

 other value above that ; when at the other end, the 

 measure is of some specified small value or of any other 

 value below it. Intermediate positions represent inter- 

 mediate values according to the scale. Each of the 

 cards corresponds to one of the sets of measures in 

 the standard collection. The set of measures of the 

 given person are indicated by the positions of parallel 

 strings or wires, one for each measure, that are stretched 



Fig. 5. — Section of the apparatus, but the bridge and rod are not shown, only the section of the wires. 



K ,j 



Fig. 6a. 



Plan and section of the key -board k. 



Fig. 7. — Reduced plan of complete apparatus. 



Explanation:— a, the common axis ; ci, C2, the cards ; t, tilting-frame, turning on A (the cards rest by their front ends on F, the front cross-bar of T, 

 at the time when the heavy hinder end of T rests on the base-board s) ; K, key-board, in which R, R are the rods between which the wires stretch ; 

 b, b, are the bridges over which the wires pass. 



across bridges at either end of a long board set cross- 

 ways to the cards. Their positions on the bridges are 

 adjusted by the same scale as that by which the notches 

 were cut in the cards. Figs. 6a and 6b are views of this 

 portion of the apparatus, which acts as a key, and is of 

 about 30 inches in effective length. The whole is shown 

 in working position in Fig. 7. When the key is slid into 

 its place, and the heavy end of the tilting-frame T is 

 raised, all the cards are free to descend so far as the 

 tilting-frame is concerned, but they are checked by one 

 or more of the wires from descending below a particular 

 level, except those few, if any, whose notches correspond 



throughout to the positions of the underlying wires. This 

 is the case with the card ci, drawn with a dotted outline, 

 but not with c\, which rests upon the third wire, counting 

 from the axis. As the wires have to sustain the weight of 

 all or nearly all the cards, frequent narrow bridges must 

 be interposed between the main bridges to sustain the 

 wires from point to point. The cards should be divided into 

 batches by partitions corresponding to these interposed 

 bridges, else they may press sideways with enough friction 

 to interfere with their free independent action. Neither 

 these interposed bridges nor the partitions are drawn in 

 the figure. The method of adjusting the wires there shown 



