A record of the direction of the wind was made after Andree's departure, and proved that there was a fluctuation in direction from S.W. to N.W., indicating that the voyagers may have been borne across towards Siberia. This, however, can be but surmise. All aeronauts of experience know that it is an exceedingly difficult manoeuvre to keep a trail rope dragging on the ground if it is desirable to prevent contact with the earth on the one hand, or on the other to avoid loss of gas. A slight increase of temperature or drying off of condensed moisture may--indeed, is sure to after a while--lift the rope off the ground, in which case the balloon, rising into upper levels, may be borne away on currents which may be of almost any direction, and of which the observer below may know nothing. As to the actual divergence from the wind's direction which a trail rope and side sail might be hoped to effect, it may be confidently stated that, notwithstanding some wonderful accounts that have gone abroad, it must not be relied on as commonly amounting to much more than one or, at the most, two points. Although it is to be feared that trustworthy information as to the ultimate destination of Andree's balloon may never be gained, yet we may safely state that his ever famous, though regrettable, voyage was the longest in duration ever attained. At the end of 48 hours his vessel would seem to have been still well up and going strong. The only other previous voyage that had in duration of travel approached this record was that made by M. Mallet, in 1892, and maintained for 36 hours. Next we may mention that of M. Herve, in 1886, occupying 24 1/2 hours, which feat, however, was almost equal led by the great Leipzig balloon in 1897, which, with eight people in the car, remained up for 24 1/4 hours, and did not touch earth till 1,032 miles had been traversed. The fabric of Andree's balloon may not be considered to have been the best for such an exceptional purpose. Dismissing considerations of cost, goldbeaters' skin would doubtless have been more suitable. The military balloons at Aldershot are made of this, and one such balloon has been known to remain inflated for three months with very little loss. It is conceivable, therefore, that the chances of the voyagers, whose ultimate safety depended so largely upon the staying power of their aerial vessel, might have been considerably increased. One other expedient, wholly impracticable, but often seriously discussed, may be briefly referred to, namely, the idea of taking up apparatus for pumping gas into metal receivers as the voyage proceeds, in order to raise or lower a balloon, and in this way to prolong its life. Mr. Wenham has investigated the point with his usual painstaking care, and reduced its absurdity to a simple calculation, which should serve to banish for good such a mere extravagant theory.