ON “QtUET” DAYS DURING THE ELEVEN YEARS 1890 TO 1900, ETC. ;197 
The results tlms obtained appear in Table XXXI. Tliey should be regarded as 
affected by an uncertainty of the order of a day through the treatment of the 
months as of uniform length. 
The maximum in the annual term appears in general near midsummer, and would 
seem somewhat earlier in D and V than in I and H. The first maximum in the semi¬ 
annual term appears generally late in March or early in Api'il. 
Table XXXI.—Annual Variation. Date of Occurrence of First Maximum. 
Annual term. 
Semi-annual term. 
D. 
I. 
H. 
Y. 
D. 
I. 
II. 
Y. 
Ranges .... 
June 26 
July 8 
July .3 
June 19 
March 30 
April 1 
April G 
xipril 16 
21 differences . . 
27 
,, 8 
„ 3 
„ 20 
„ 21 
„ 4 
)) 8 
„ 10 
Cl . 
„ 27 
„ 6 
„ 3 
„ 22 
„ 15 
„ 3 
„ 6 
„ 26 
Co. 
., 25 
,, 18 
0 
n ^ 
„ 20 
April 1 
„ 26 
„ 16 
„ 13 
C 3 . 
„ 20 
„ 21 
„ 31 
„ 17 
March 30 
March 20 
March 22 
IMarch 29 
Ci . 
Dec. G 
Nov. 5 
Nov. 25 
May 29 
„ 27 
„ 21 
^ t 
,5 ^ i: 
April 7 
“ Variahility” of the. Dedination. 
^ 39. In discussing magnetic ol)servations made during the recent “ Southern 
Cross” Antarctic Expedition,* I made a comparison of what I called the “Variability 
of the Declination” at Cape Adare and at Kew in 189!). I have made a similar 
investigation into the data at Kew during the remainder of tlie period 1890 to 1900, 
partly with a view to seeing whether the phenomenon is of sufficient definiteness and 
regularity to afford a satisfactory basis for inter-comparison of stations. 
It is customary at Kew, during absolute observations, to take two declination 
readings with the magnet’s scale erect, and three with it inverted. These readings 
show the changes taking ])lace in D during three intervals in wliich the magnet has 
remained untouched, the length of an average interval being about 4 minutes. The 
observations have mostly been made at a time of the day when the regular diurnal 
change is slow. The same instrument has been in use throughout, the procedure has 
varied but little, and the same observer has been responsible for the great majority 
of the observations. Thus the results for different months and years are fairly 
comparalffe. 
The plan I have adopted has been to sum up all the changes in reading in a year, 
‘Magnetic and Meteorological Obsei’vations made l^y the “Southern Cross'’ Antarctic Expedition 
1898-1900,’ p. 21. 
