IN view of the interest recently displayed in theories as to the origin of magnetic disturbances, attention may be directed to some rather curious phenomena exhibited during the magnetic storms experienced lately. Usually when a magnetic element during a storm suffers a large deviation in one direction it does not simply return to, but overshoots, its original value, and oscillates about its undisturbed position. If we liken the curve to the outline of an island on a map, a conspicuous indentation of the coast line is usually accompanied by a correspondingly pronounced promontory. Whilst this is much the more common phenomenon, it is by no means very unusual to have, as it were, an isolated bay in an otherwise straight coast line; only when this happens the “bay” seldom forms a deep indentation, and the curvature of its outline is seldom very great. On November 15, during the recent display of aurora, a somewhat remarkable instance of a nearly isolated “bay” presented itself in the declination curve trace at Kew. Taking, again, the geographical analogy, it resembles—as may be seen from the accompanying copy of the curve1—a regular estuary. We have, commencing at 8.53 p.m., an easterly movement, which in twelve minutes reduced the declination about 32′, while in the subsequent twenty minutes the declination increased 34′, thus returning very nearly to the value it had half an hour before. This was by no means the only movement during the magnetic storm of November 15, but it was far and away the most conspicuous one. Its remarkable form would predispose one to attribute it to some very special cause, which one would naturally associate with the coexisting aurora. Curiously, however, a very similar movement was experienced three days earlier, when no special auroral display seems to have been noted in this country, the intervening days being free from any large disturbance. This earlier disturbance—a copy of which is also shown—took place on November 12, also in the evening, but nearly 21/2 hours earlier than that on November 15. The conspicuous movement on November 12 began about 6.30 p.m. The easterly movement was fully larger than on November 15, being about 35′.5 while the return swing to the west was about 36′.5. The double movement occupied about thirty-eight minutes, and so somewhat longer than on November 15, but this is chiefly due to the movement on November 12 beginning and ending somewhat less abruptly.