Note 36 — Chapter VII · THE MARCH TO FUGA. ASCENT OF THE HIGHLANDS OF EAST AFRICA. PRESENTATION TO KING KIMWERE.

A delicate mercurial barometer (Adie), obligingly lent to me by the Secretary of the Bombay Geographical Society, was left for comparison at Zanzibar with the apothecary of the Consulate. On a rough mountain tour such an instrument would certainly have come to grief, as it afterwards did on the lowlands of the Continent. The instruments recommended by the Medical Board, Bombay, did not reach us in time; and the same was the case with the reflecting circle kindly despatched by Mr Francis Galton. We had in all four bath thermometers, and two B. Ps.; one used by Capt. Smyth, R. N., when crossing the Andes, was given to us by Col. Hamerton; and another (Newman) was rendered useless by mercury settling in the upper bulb, air having been carelessly left in the tube by the maker—a frequent offence. We had no sympiesometers. The instrument is portable, but the experience of naval officers pronounces against it within the tropics, and especially near the Line (6° to 8°), where its extreme sensitiveness renders it useless. Aneroids also must be carried in numbers, and be compared with standard instruments not so likely to be deranged: they are seldom true, and are liable to vary when ascending or descending the scale. My latest explorations have been made with glass tubes, supplied by Mr Louis Casella, of Hatton Garden: they are portable, not easily broken, and, best of all, they give correct results. Of course it is well to carry aneroids for all except crucial stations; and as for B. Ps., they are not worth the trouble of carrying.