1893. ] NEW YORK ACADEMY OF SCIENCES. 133 
1624. This pharmaceutical work contain nineteen full-page 
plates engraved with delicate skill. 
In Kircher’s Mundus Subterraneus (1665) are engraved numer- 
ous forms of furnaces and stillatories, largely copied from 
Donato d’ Eremita’s work. 
J. J. Becher, in his account of a ‘‘ Portable laboratory ’’ 
(1719), exhibits on a single plate sixty-four different articles, 
including the following: Crucibles, muffles, cupels or tests, 
moulds for making cupels and for casting metals, mortars, 
mills for grinding, bellows, tongs, forceps, a tripod for gsupport- 
ing dishes, a rabbits-foot for brushing powders, a hand screen 
to protect the face from heat, various vessels of wood, copper, 
and iron, scales for weighing (three styles), retorts, phials, 
funnels, bladders, besides an apron, a towel, a linen jacket, an 
hour-glass, candles and tobacco-pipes! 
Straw-rings for supporting round-bottomed vessels are 
pictured in Lefevre’s Traité (1669). 
The interior of the University laboratory at Utrecht, under 
the direction of Johann Conrad Barchusen, Professor of 
Medicine and Chemistry, is neatly figured in his Pyrosophia, 
published 1698. In this, as in others of the period, the promi- 
nence given to furnaces reflects the importance attributed 
to operations by fire. 
Physical instruments of chemical application were slower in 
developing ; thermoscopes appeared early in the seventeenth 
century and thermometers somewhat later.* Torricelli dis- 
covered the barometer in 1643, and Pascal tested its utility on 
the Puy-de-Dome five years later. 
Otto de Guericke’s air-pump and frictional electric machine, 
together with the interesting experiments conducted with the 
Magdeburg hemispheres are handsomely depicted in his 
celebrated treatise De vacuo spatio, published in 1672, This air- 
pump and the hemispheres are preserved in the Royal Library, 
Berlin. The Hon. Robert Boyle improved Guericke’s air-pump 
in 1659, and used it in laying the foundations of pneumatic 
chemistry, a field that from this time occupies our attention 
almost exclusively. Boyle’s air-pump and accessory apparatus 
are figured in plates accompanying the several editions of his 
works, 
As is well known the earlier chemists paid little or no atten- 
tion to gases though they were familiar with processes which 
__. *Geber remarks that “ Fire is not a thing which can be measured, therefore 
it happens that error is often committed init.” He evidently felt the need of 
thermometers. 
