506 



PKOFESSOR W. E. AYRTON, MR. T. MATHER AND MR. F. E. SMITH: 



is represented on the curve by a length of 100 millims., the magnification is over 1000.* 

 In spite of this large magnification the resulting lines are fairly regular, a fact which 

 bears eloquent testimony to the excellence of workmanship and definiteness of 



STEADINESS or B*>L*NCC UNOCR VARIOUS CONDITIONS 



101-5 



Cmxt'T T 



Lc 



.OIL* 



101 



1005 



NoC 



CNT. 



\ 



\ BOTH 



7 Cl 



100 



99-5 



E.NT 



93-0 



Pf RIO >S 



(= 



SECOM 



09, 



tMT HAN > COILS 



2 



5. 



Fig. 20. 



behaviour of the instrument. The perfection of the arrangements for reading the 

 scale are also of a high order, seeing that 1 millim. on the ordinates of the curves 

 corresponds to a length of less than 1 micron (TO^OO millim.) on the scale, and the 

 regularity of the curves shows that the scale can be read to an accuracy of this order 

 under favourable conditions. 



In fig. 20 the scale is alx>ut T 'o f tnc original. 



