M ETF.OH 01,0 GY.

23

£

Filtering cup, shewing the porosity of vegetable bodies 0 Plate and piece of wood, for the same experiment . 0

The double transferrer, which transfers a vacuum from

one receiver to the other . . £2 to 3

Flat plate, with sliding wire and collars of leather . ' 0 Ground plate, brass box, and iron heater, for experi­ments on gunpowder in vacuo . . .1

Hollow glass figures, for rising and falling in water,

according to the rarefaction of the air, 3s. to 0 Large bell ground receivers, for air pumps . 15s. to 1

Small ditto . . . . . . 5s. to 0

Long fountain glasses . . . 14s. to 1

Guinea and feather receivers . . . 18s. to 2

Receivers, ground at each end, or made to pattern or order ........

METEOROLOGY.

Complete set of meteorological instruments, consisting of best iron cistern barometer, two thermome­ters for registering the maximum and minimum of temperature, parabolic radiating mirrror with thermometer, Daniels hygrometer, with printed instructions and tables, rain gauge and evapo­rating ditto, with glass measure, as recom­mended by L Howard, in his climate of Lon­don ..... £15 15s. to 21

Standard barometer, with open cistern, as made by J. N. for the Royal Society, and described in Mr. Daniells Meteorological Essays . . 20

Portable ditto, with corrections, and every requisite

for keeping a correct register . . .8

Sir H. Davys compensation barometer, with iron cis­tern . . . . . . . .10

Newmans portable mountain barometer, with iron cis­tern, and printed instructions . . .6

s. d.

5 0

4 6

0 0 12 6

10 0

5 0 15 0 10 0 10 0 10 0

0 0

0 0 8 0 0 0 6 0