PKOF. W. M. HICKS: A CKITICAL STUDY OF SPECTRAL SERIES. 



103 



* SCHNEIDERJOST, ' Beibliitter,' xxviii., p. 1175. 



The agreement between observed and calculated is very good except for S' (2) and 

 S" (2), which is in accordance with what has been found in the previous cases. As 

 mentioned above, these were left out in finding the constants, as the chief end was to 

 get accurate values of N, and there was some doubt as to the form of the S formulae 

 being correct. In compai'ison of RAYLEIGH'S lines we found probable errors in R. and 

 P.'s measurements, amounting to eight or ten times their estimates. If we take their 

 possible errors as only three times their estimates, very few of the calculated values 

 overstep these limits. It is interesting to note that the least square treatment 

 corroborates independently the errors determined from RAYLEIGH'S interference 

 standards. Thus, in P'(2), the differences in n for m = 1.2.3.4 are '024, +'12, 

 '03, '03, pointing to considerable error in P' (2). If the calculated correction of 

 II. be applied to R. and P., the difference should have been '28. This would have 

 been in the course - 024, '28, '03, and then the method of least squares would 

 have brought these into close agreement. In fact, the considerable error in P' (2) has 

 pulled the calculated values for P'(l.3.4) out of their proper places. A similar result 

 is shown in S". If the calculated wave-length values of 8(2.3) be compared with 

 R. and P.'s corrected values from II., the differences would be 275, '007, '007, instead 

 of 2'84, '026, '007, and if they had been used to calculate the constants the agree- 

 ment would have been much closer. So the differences for D (2) would be diminished 

 from -545 to '525, but D (3) increased from to -'019, D (2.3) increased from '005, 

 006 to -'064, -'024. 



The values of N may be expected to depend to a few units on the weights allowed, 



