Oscillations in Coupled Circuits. 



37 



768 tuning-fork photographed simultaneously. In general 

 appearance the photographs closely resemble the calculated 

 curves, figs. 1, 2, 3,4, but in order to obtain a more accurate 

 comparison the maximum ordinates and the time-intervals 

 corresponding to the minima of the wave -curves were 

 measured. These measurements were made on the negatives 

 with a travelling microscope. 



In determining the minima, a fine line ruled on the plate 

 at right angles to the zero line of the curve was used as line 

 o£ reference, and the time-interval between the first minimum 

 and the eighth or ninth after the starting-point, determined 

 by the method described in the previous paper. The intervals 

 between the first minimum and the second, third, fourth, 

 <fec, were then taken as proportional to the corresponding 

 lengths on the plate. The starting-point was not used in 

 these measurements as, owing to the initial slope being zero, 

 it is difficult to determine exactly the point at which the 

 curve first begins to ascend. 



In Table III. are given tbe time-intervals in thousandths 

 of a second of the first eight or nine zeros (measured from 

 the first) of the secondary potential as determined from the 

 photographs and as calculated approximately from (o) and 

 the curves, figs. 1, 2, 3, 4. 



Table III. 



No. of 

 Zero. 



Case I. 



Case II. 



Case III. 



Case IV. 



t 103 obs. 



1 10^ calc. 



1-04 

 0-76 

 1-59 

 2-76 

 3-53 

 4-36 

 5 53 

 6-36 



t 103 obs. 



1 



t 10 3 calc. 



t 10 3 obs. 



1 103 calc. 



■t 103 obs. 



t 10 3 calc. 



Origin 

 2 

 3 

 4 

 5 

 6 

 7 

 8 

 9 



0-7553 



1-579 



2-762 



3-549 



4-382 



5-537 



6*357 



0-7283 



1-452 



2-619 



3-395 



4-132 



4-962 



6019 



6814 



0-98 

 0-72 

 1-45 

 2-60 

 3-37 

 412 

 4-99 

 5-99 

 6-75 







7773 



1-586 



2855 



3-714 



4542 



5-409 



6-585 



7462 



1-10 



0-78 

 1-60 



2-85 

 3-70 

 4'55 

 545 

 660 

 747 



0-7713 



1-530 



2-596 



3-558 



4-342 



5-141 



6-166 



7-129 



103 

 0-77 

 1-54 

 2-57 

 3-55 

 4-34 

 5-15 

 6-15 

 7-07 



The zeros of 2V 2 calculated from (3) therefore agree 

 closely with those determined from the photographs. 



