760 



DR E. M. WEDDERBURN AND MR A. W. YOUNG ON 



TABLE IV. 



No. of 



No. Specifying 



No. of 



No. Specifying 



No. of 



No. Specifying 



No. of 



No. Specifying 



Interval. 



Depth. 



Interval. 



Depth. 



Interval. 



Depth. 



Interval. 



Depth. 



1 



168 



36 



70 



71 



619 



106 



319 



2 



166 



37 



96 



72 



611 



107 



349 



3 



217 



38 



173 



73 



670 



108 



353 



4 



423 



39 



330 



74 



612 



109 



349 



5 



588 



40 



431 



75 



635 



110 



359 



6 



552 



41 



609 



76 



661 



111 



372 



7 



535 



42 



834 



77 



641 



112 



395 



8 



475 



43 



866 



78 



595 



113 



449 



9 



207 



44 



894 



79 



585 



114 



493 



10 



137 



45 



962 



80 



578 



115 



522 



11 



88 



46 



941 



81 



483 



116 



469 



12 



108 



47 



922 



82 



447 



117 



431 



13 



246 



48 



871 



83 



432 



118 



379 



14 



243 



49 



851 



84 



411 



119 



381 



15 



344 



50 



842 



85 



392 



120 



336 



16 



474 



51 



791 



86 



379 



121 



330 



17 



581 



52 



748 



87 



398 



122 



356 



18 



673 



53 



715 



88 



408 



123 



364 



19 



729 



54 



667 



89 



545 



124 



355 



20 



750 



55 



607 



90 



606 



125 



377 



21 



791 



56 



542 



91 



600 



126 



363 



22 



742 



57 



479 



92 



599 



127 



335 



23 



701 



58 



409 



93 



550 



128 



333 



24 



578 



59 



356 



94 



430 



129 



299 



25 



550 



60 



296 



95 



453 



130 



318 



26 



557 



61 



227 



96 



454 



131 



359 



27 



569 



62 



204 



97 



440 



132 



382 



28 



534 



63 



290 



98 



472 



133 



466 



29 



582 



64 



502 



99 



500 



134 



554 



30 



534 



65 



558 



100 



494 



135 



572 



31 



448 



66 



687 



101 



512 



136 



624 



32 



400 



67 



808 



102 



478 



137 



610 



33 



346 



68 



727 



103 



403 



138 



586 



34 



167 



69 



689 



104 



389 



139 



585 



35 



86 



70 



679 



105 



359 



140 



620 



It will be seen that there are only 140 observations in all, whereas in an 

 astronomical investigation there may be a thousand or more. Hence if the largest 

 trial period covers, say, 25 of these observations, there are only 5 com- 

 plete periods available. If the smallest trial period covered 10 observations, 5 

 periods would only make use of 50 of the observations, but it was thought best to 

 make use of all the available observations for each trial period. By this procedure 

 the smaller periods will have greater weight given to their amplitudes than the 

 longer periods, but it is easily seen that the increase of amplitude will be roughly 

 inversely proportional to the length of the trial period. Hence, to reduce all the 

 amplitudes to a uniform scale each must be divided by the number of "laps" used 

 in determining the amplitude. 



Examples are given of the 10 and 20 trial periods in the following tables : — 



