CHE to the most superficial observer ; for this knowledge essentially con- tributes to the improvement ot' all the productions of Nature and Art. Thus, the husbandman, the artisan in general, the brewer, distiller, soap-manufacturer, nay, even the baker, and the cook, mav avoid many errors and disappointments, if they are but tolerably acquaintrd with the first principles of an art, which daily administers to our comforts and necessities. The history of chemistry is in- volved in obscurity : Hermes TmsMEcrsTUS, a noble Egyptian, who lived lpOO years before the Christian aera, is said to be its in- ventor ; though Mo sf.s, the legis- lator, probably possessed some knowledge of this captivating science. Previous to the time of Eoger Bacon, an English Friar of the 13th century, the whole was involved in mystery, and alche- mical jargon. Like a blight star in a dark hemisphere, this genius de- monstrated to his superstitious bre- thren, that, by studying Nature, and reducing her powers within the rules of Art, he could produce effe6ts, which far surpassed the miracles of vaunting magicians, while they dispelled the whole- tribe of charms, sorceries, and in- cantations. Nay, it is admitted, that he invented, but carefully con- cealed, the composition of gun- powder. But his deluded cotem- poraries were not to be rescued from the grossest superstitious no- tions, till the way bad been paved by the reformation of Luther ; and another luminary arose, who was placed in circumstances more favourable to excite attention, and ensure respect to his doctrines. This was the illustrious Hook, v/ho laid the foundation of cbemi- CHE [ 5 o 5 cal science in Britain. Others, indeed, on the Continent, such as Paracelsus, Van Helmont, and Sir Theodore Mayerne, the last of whom afterwards spent thirty years in England, had suc- cessfully laboured for the improve- ment of chemistry ; but the first of these was an impudent juggler; and the second, a credulous votary of the Paracelsian svstem. Van Helm o nt, however, mustbe allow- ed to be the original discoverer of gaseous, or aenform bodies ; for which discovery he was called a magician, and imprisoned by the dark tribunal of the inquisition. Dr. Hook proved, 1. That the air in which we live, move, and breathe, is the universal solvent of all inflammable bodies ; 2. That it does not perform this action till the body be first sufficiently heated ; 3. That this process of dissolution generates a very great heat, or what is called fire ; 4. That light is also produced from this action ; 5. That these phenomena do not arise from the air itself as an ele- ment, but from that part of the air which is inherent in it, and is like, it not the very same, as that which is feed in salf-petre. Thus we find that the foundation was laid for the subsequent discoveries of Boyle, Ma yow, and Hales, who first ascertained the exact quantity ot air, or an elastic fluid analogous to air, either produced or absorbed by the burning of sulphur, or of candles, or by the respiration of animals. Hence, the last men- tioned philosopher compares the air to " a true Proteus, now fixed, now volatile, entering into the com- position of bodies, where it exists in a solid form, deprived of elasti- city, and of those properties which formerly distinguished it, adding gravity
