1878.] 



Declination at Trevandrum. 



83 



change of type, that about the times of the equinoxes there is not 

 only a small average value of the range, but likewise an uncertainty 

 about its character, as it sometimes appears to be of the one type and 

 at other times changes to the other type. 



B. Variations of Long Period. 



4. In order to investigate the long-period variation of the Trevan- 

 drum declination-range, I have treated these observations precisely in 

 the way in which the Kew declination-ranges were treated (Proc. 

 Roy. Soc, March 22, 1877). By this method proportional values of the 

 declination-range at Trevandrum have been obtained corresponding to 

 weekly points for each year, and it is believed that these values are 

 freed from any recognised inequality depending either on the month 

 of the year or on the relative position of the sun and moon. If this 

 method should be found to furnish nearly the same results in the case 

 of two observatories so widely apart as Kew and Trevandrum, and 

 with such marked differences in the annual variation of the declina- 

 tion-range, we may conclude that this separation of inequalities has 

 been successfully accomplished. The proportional values of the 

 Trevandrum declination-range are given in Table II. 



Table II. — Exhibiting monthly means of declination- range for weekly 

 points, the mean value of the range for the whole series for each 

 point being reckoned = 1,000. 



(The date of the first point for each year is given.) 



1854. 



1855. 



1856. 



1857. 



1858. 



1859. 



1860. 



1861. 



1862. 



1863. 



1864. 



Jan. 4 



Jan. 3. 



Jan. 2. 



Jan. 7. 



Jan. 6. 



Jan. 5. 



Jan. 4. 



Jan. 2. 



Jan. 1. 



Jan. 7. 



Jan. 6. 



1078 



876 



805 



873 



1163 



1126 



1166 



945 



1093 



1132 



844 



1038 



888 



832 



891 



1118 



1132 



1099 



889 



1075 



1122 



890 



943 



915 



917 



918 



1113 



1128 



1094 



908 



1014 



1189 



910 



932 



909 



976 



896 



1062 



992 



1120 



931 



959 



1260 



981 



934 



942 



1000 



928 



988 



1012 



1113 



846 



998 



1204 



1054 



944 



955 



946 



978 



1050 



1005 



1157 



854 



947 



1120 



1076 



976 



894 



853 



989 



999 



1110 



1203 



823 



1011 



1026 



1089 



950 



922 



765 



928 



1007 



1183 



1292 



951 



1056 



1010 



958 



895 



907 



707 



890 



1094 



1157 



1411 



1030 



1050 



990 



889 



925 



895 



694 



786 



1095 



1221 



1367 



1060 



1080 



1074 



796 



939 



931 



733 



764 



1098 



1116 



1416 



1066 



1037 



1107 



806 



962 



929 



767 



789 



1083 



1064 



1454 



986 



1031 



939 



945 



1011 



978 



802 



761 



1160 



1105 



1290 



981 



971 



962 



967 



970 



955 



850 



779 



1111 



1094 



1406 



996 



977 



919 



948 



1030 



934 



829 



804 



1124 



1206 



1288 



925 



952 



990 



922 



999 



983 



764 



877 



1033 



1291 



1206 



903 



974 



1030 



915 



1023 



935 



707 



1027 



960 



1283 



1219 



945 



981 



1023 



920 



1106 



940 



669 



1053 



1013 



1239 



1155 



895 



916 



1074 



928 



1040 



949 



683 



1053 



992 



1177 



1185 



932 



951 



1040 



982 



1042 



873 



731 



992 



1069 



1117 



1189 



985 



942 



1079 



1025 



996 



895 



748 



877 



1015 



1099 



1205 



965 



1021 



1068 



1098 



927 



878 



755 



856 



970 



1147 



1181 



1031 



1091 



1036 



1137 



939 



882 



755 



805 



953 



1130 



1175 



1096 



1098 



1021 



1143 



950 



918 



780 



827 



962 



1096 



1183 



1111 



1099 



975 



1088 



g2 



