EXAMINATION OF INSTRUMENTS—TACKING. 
9 
5s.; superior sextants, 5s. Unifilars, dip circles, and other magnetic 
instruments are also verified. The carriage of the instruments to and 
from the Observatory must be paid. Address—■“ Superintendent of the 
National Physical Laboratory, Richmond, Surrey.” The establishment 
lies ten minutes’ walk from the Richmond railway station. Any persons 
ordering instruments from opticians may direct them to be previously 
forwarded there for verification. They can be sent direct, or through the 
receiving establishment at the Meteorological Office, 63, Victoria Street, 
Westminster, S.W. 
Packing . 
It is difficult to give general rules, because the modes of transport 
vary materially in different countries. Inquiry should be made by the 
intending traveller at the Royal Geographical Society’s rooms as to the 
kind of packing best suited for his special purposes and field of 
exploration. The corners of all the instrument cases should be brass- 
bound; the fittings should be screwed, and not glued; and the boxes 
should be large enough to admit of the instruments being taken out and 
replaced with perfect ease. Instrument makers are apt to attend over¬ 
much to compactness, making as much as possible go into a small box, 
which can easily be put on a shelf; but this is not what a traveller 
wants, bulk being rarely so great a difficulty to him as weight. Above 
all, it is most important that he should be able to get at his instru¬ 
ments easily, even in the dark. He should notice particularly the manner 
in which the instrument is placed in its box, before taking it out, and in 
the case of a theodolite , observe the positions of the verniers , and the object end 
of the telescope; attention to this will prevent much loss of time and 
possible injury to the instrument. Moreover, a large, light box suffers 
much less from an accidental concussion than a small and heavy one. 
Thermometers travel best when slipped into india-rubber tubes in a brass 
casing. A coil of such tubing will serve as a floor, to protect a case 
of delicate instruments from the effects of a jar. Horse-hair is of use to 
replace old packing, but it has first to be prepared by steeping in boiling 
water, twisting into a rope, and, after it is firmly set, chopping it into 
pieces. The hairs retain their curvature and act as springs. Instruments 
travel excellently when packed in loose , tumbled cloths. 
