646 PROFESSOR PIAZZI SMYTH ON THE 
physics generally, what they have done with universal commendation, for the 
Moon during two centuries ; viz., kept a Royal Observatory continually observ- 
ing it, until at last the said Observatory is able, now very nearly, to predict the 
Lunar places for future years from its own observations, and with all the 
extreme accuracy demanded by the advanced national requirements of the 
present time. 
APPENDIX 
No. I. 
(Contract for the New Rock Thermometers.) 
Estimate by ALEx. ApIE & Son, 50 Princes Street, Edinburgh, for Underground and Standard 
Thermometers to be placed at the Royal Observatory, Edinburgh. 
6th February 1877. 
Six thermometers of the following lengths, including the scales above 
ground:—One 23 feet, one 13 feet, one 6 feet, one 4 feet, one 2 feet, one 1 foot, 
to hang in air-box. These thermometers to have gun-metal scales, with a strip 
of platina half-an-inch wide inlaid in the gun metal to receive the graduations 
and resist oxidation. The bulbs of four of the above thermometers to be cased 
in copper cylinders, and packed therein with fine clay. Iodine to be used for 
colouring the alcohol. The thermometers to be carefully compared weekly and 
daily, with three mercury standards to be, as below, from the time of being 
made until insertion, that is while the temperature permits this being done, . £140 0 O 
The three necessary mercurial standard thermometers above alluded to, 
to be prepared with all necessary attention to high scientific accuracy, finished 
with scales like the first six, to be 16 inches long, and to range from 30° 
to 220°. . : : : : : 2 : 5 . 18" U0 
A pine wood box with luffer-boards, made for free ventilation, fastened to 
the rock with copper fastenings, the door to have a brass lock and hinges; also 
one pine wood box to fit outside the above, to be 7 inches free all round, and to 
be fastened to the rock with copper bolts, the door locked with a brass lock. 
The doors of these two boxes to open outwards only, . : ; : 17,050 
Preparing well of rock in Royal Observatory grounds to receive thermo- 
meters, and filling same after insertion of the thermometers with fine clay, . 21 10, 40 
£196 10 0 
Total amount, One hundred and ninety-six pounds ten shillings, The whole of the 
work to be performed to the satisfaction and approval of the Astronomer Royal for Scotland, 
who is to have the power to vary the specified length of the long thermometers to the extent 
of 30 inches each. All the above work to be maintained in good condition by our firm for the 
space of twelve months. 
(Signed) ALEX, ADIE & Son. 
* The lengths for the five principal thermometers as eventually constructed were, from the surface of the ground 
down to the centre of each bulb, 4/=250 British inches ; ?=125; t?=50; 44=25; 1®=1; while above the surface of the 
ground every thermometer had 30 inches additional of scale length. 
