4 
HINTS TO TRAVELLERS. 
candles can be carried. See that there is abundant supply of 
air-holes in the sides ; these are essential when the lantern is set 
upon the ground. Also that all the internal fittings can be 
removed and cleaned, and that they are solidly made, not merely 
soldered. It should be furnished with a reflector, to throw a clear 
light forwards and downivards. A moveable shade of light green 
glass will be found to be a great improvement, as it prevents the 
light from dazzling the eyes, and enables the observer to take the 
reading on the sextant with greater ease. A good lantern is most 
important . For general purposes, the Italian Alpine Club lantern 
is one of the best forms, A small ball of spare wick, oil of the best 
quality obtainable, and wax tapers, for use on detached expeditions, 
should also be taken. 
Thermometers — 
Several sling thermometers. 
A pair of wet and dry bulb thermometers. 
A pair of maximum and minimum thermometers, fitted in one 
case. 
Three short and stout boiling-point thermometers, with apparatus 
for boiling them. (See p. 13 for further particulars.) 
Two ordinary thermometers, which should be graduated from 20° 
or more below the freezing- to above the boiling-point. For 
very cold climates, spirit thermometers should be taken. 
Standard thermometers, at a charge of 11 . each, graduated at the 
National Physical Laboratory, Richmond, Surrey, may be obtained 
thence, on the application of any Fellow of the Royal Society, or 
Member of the British Association. 
Aneroids— 
Aneroids of ordinary construction should be of large pocket size 
(2 2 inches across). They can be obtained graduated up to 20,000 
feet at most instrument makers. At any such height, however, 
their records can never be depended on. Aneroids are excellent 
for most differential observations, but unreliable for absolute ones; 
they should be observed, as much as possible, in conjunction with 
