8 REPORTS ON THE STATE OF SCIENCE.—1918. 
figures given in the table were read from a smoothed curve. In the third 
column is given the corresponding quantity calculated from the adopted 
tables in use, followed in the fourth column by the differences O—C,. 
In the next column O—C, is shown the effect of correcting these tables 
as in Table II. of the 22nd Report. It is seen at a glance that the tables 
are considerably in error, and that the suggested corrections reduce the 
errors. But before deciding to attempt any further reduction let us 
turn to the observations of SR,, of which the following were collected :— 
Tasie IV. 
Observed Values of SR. 
SP > S8R Se dee SeP (HH =s “Gigge 
s. s. s. | Ss. s. s. 
363 149 214 | 574 282 292 
366 146 220 578 291 287 
372 162 210 583 297 286 
397 195 202 
(374) (163) ~—=s((211) (578) (290) (288) 
525 234 291 : 606 332 274 
530 249 281 634 341 293 
541 266 275 647 382 265 
542 263 279 673 357 316 
550 257 293 
(538) (254) — (284) (640) (358) ~—«(287) 
The records of SR, are often given to tenths of a minute only, 
suggesting some uncertainty; more observations are desirable, but 
those above quoted are consistent in showing that the difference (S—P) 
— (SR,—8) or 28S—P—SR, is sensibly constant from (say) S—P 
=520 seconds to 680 seconds, which may serve as a useful check. 
Comparing the means (in brackets) with the adopted tables, we get 
the differences O—C, while the corrections of the 22nd Report give 
the column O—C,. 
TABLE V 
3 Psy 
S-P A Cal. =| Oban | | O80, ce O-C, 
8. 0. 8. | 8. 8. | S. 
374. | «408 pe am a 21 —-1 | 46 
538 | = 68-0 220 | * 284 +64 | +33 
BIBS <i). ose 241 288 +47 | +21 
640 | 865 272 287 +15 | +9 
We again see at a glance that the adopted tables are sensibly in error, 
and that the corrections found in the 22nd Report, while they reduce 
these errors, do not annihilate them. We must proceed further in the 
same direction. 
Tt is easily seen that the further alterations must be chiefly in SR,, 
and not in § (or P). Thus let us fix attention on the worst case,-where _ 
S—P=538s. For this value of S—P the adopted tables give A=68°-0 ; 
but when we correct the tables we get A=69°-2. Note that S—P is 
