Page:Proceedings of the Royal Society of London Vol 60.djvu/138

Rh chronological, b u t in descending order of the voltages observed at station A. In all the tables the humidity of saturation is taken as 100.

§ 21. I have divided the results in each of the previous eight tables into two groups, according to the order of voltages at station A. The two groups are equal in number of constituents, except as regards Table XV, where, following a marked line separating the voltages, I have included six in the first group, and seven in the second; and Table X, where I have included four in the first group, and three in the second. In the last-mentioned case, the best line of demarcation is doubtful, and, on account of this, and the small number of constituents, little weight can be attached to the results.

It may seem arbitrary to determine the groups by reference to station A exclusively. It is, however, the station least influenced by buildings, and best fitted for accurate readings, while B is the worst. Also it will be seen that if one had adopted either C, D, or E as the standard station, or had taken a mean from all the stations, whilst the order of the constituents would in some tables have been considerably affected, the groups themselves would have suffered little or no change.

Table XVII gives the mean potentials at station A for each group in the several series of observations, with the corresponding mean values of the meteorological elements.