106 On a Proposed New Method of Weighing, 



and the rider is to be placed on the slider of the same side 

 ready for use. Before commencing work, we place the 

 pound weight in the pan, and adjust, if necessary, the 

 tongue of the beam so as to effect an equipoise. We remove 

 the 10-grain weight and substitute, in order, our trial pieces; 

 as we now effect an equipoise with each of these, we are 

 sure we obtain a weight of each exactly the same as that of 

 the 10-grain weight, and quite irrespective of the relative 

 length of the two arms of the balance, and when we have 

 cupelled and parted these, and obtained their gold in the 

 form of cornets, we place these in succession in the pan of 

 the balance and add weights until an equipoise is effected. 

 We add weights and we also use the rider, placing the latter 

 always first over the end knife-edge and moving it progres- 

 sively towards the centre of the beam. We read the 

 divisions of the beam in an order inverse to that employed 

 in the common mode of weighing. When the rider is 

 placed on the mark immediately over the end knife-edge, it 

 is read '0000 of unity ; if placed over the centre knife-edge, 

 or what is the same thing, lifted off the beam altogether, it 

 is read - 0100 of unity, and for intermediate positions, on the 

 first of the nine major divisions between the centre and end 

 knife-edges (dividing the arm into ten equal parts), it is 

 read on that nearest the end knife-edge .0010, and on 

 the others as we progress "0020, '0080, to '0090, the major 

 division nearest the centre of the beam ; for in sliding the 

 rider- weight towards the centre of the beam we are in 

 reality taking off weight, which act implies a corresponding 

 amount of gold in the cornet. Whether in the pan or on 

 the beam, our weights placed so as to effect an equipoise, 

 make up with the weight of the cornet exactly ten grains ; 

 they are in this sense the complement to the weight of 

 the cornet, and the mode of marking the weights and 

 reading the position of the rider, is that which instead of 

 regarding the real value of the weight itself, indicates 

 always the amount of which it is the complement, Thus, 

 to suppose a case, with cornets of the following weights, an 

 equipoise will in each case be obtained by the addition of a 

 single weight as marked, and by shifting the rider to the 

 position indicated in the table. 



