On the non‐cyclic change

In the following paragraphs is given a short account of the investigations, which I have made, concerning the non‐cyclic change. Although the investigations are of a somewhat fragmentary character, yet it seemed worth while to publish the results, as they contribute something, at least, to our knowledge of this non‐cyclic change. 1. The non‐cyclic change, as defined by Doctor Chree, is the difference of the two consecutive midnight‐values of the magnetic elements on a quiet day. Instead of taking the difference of the midnight‐values, I have taken the difference of the daily means on two consecutive quiet days. I have chosen the observations at the magnetic observatories of the United States Coast and Geodetic Survey, the uniformity in the selection of the quiet days for the different places being thus, I assumed, best secured. The geographical positions of these places are: Latitude Longitude(North) (West of Greenwich)° ′ ° ′Sitka57 03 135 20Baldwin38 47 95 10Cheltenham38 44 76 51Honolulu21 19 158 04Vieques, Puerto Rico18 09 65 26 (old location.)