144 APPENDIX. 
Meteorological observations, made, in various countries, on the 
earth’s surface. No opportunity ought therefore to be lost in 
making these observations. The instruments required for 
observing the Meteorological phenomena of any climate, are, 
The Portable or Adie’s Patent Sympiesometer, the Thermo- 
meter, Hygrometer, and Compass. The former instrument 
is used to determine the pressure of the atmosphere, the 
altitude of any situation above another, or above the level 
| of the sea. To obtain the altitudes from the Barometer, ob- 
servation tables are required. The Sympiesometer gives the 
altitudes, without the use of tables, and only requires a single 
process of subtraction and multiplication. 
| Besides the common use of the Thermometer, namely to 
_ ascertain the temperature of the air, it may be used for finding 
_ the temperature of springs, &c., from which a knowledge of 
| the heights may be deduced. 
The Reflecting Compass is a very useful instrument to tra- 
_ vellers. With this instrument the variations of the magnetic 
_ needle may be found, at any part of the globe, and the relative 
| position of objects determined. 
| LIST OF INSTRUMENTS USED BY NATURALISTS 
| AND TRAVELLERS. 
| Made and sold by Mr Alexander Adie, Optician and Ma- 
| thematical Instrument Maker to the King, No. 58, Princes’ 
Street, Edinburgh. 
Apte’s BAROMETER OR SYMPIESOMETER, for measuring heights 
&c., from £3 3s. to £12 12s. 
THERMOMETERS, from 8s. to 18s. 
Hycromerers, or Dew Port instrument, from £1 5s. to 
£228; 
Kurnometers, for finding the dip of stratified rocks, from 
10s. 6d. to £3 3s. 
Puorometers, from £1 ls. to £2 2s. 
The Compass Box, from 3s. 6d. to 10s. 
The Rertectinc Compass, from £2 2s. to £2 12s. 6d. 
