go in a proud habit, or plush and velvet garments, but diligently follow their labours, sweating whole days and nights by their furnaces.* They wear leather garments with a pouch, and an apron wherewith they wipe their hands. They put their fingers amongst coals, into clay and filth, not into gold rings. They are sooty and black, like smiths and colliers, and do not pride themselves upon clean and beautiful faces."

Whilst empiricism and mystic arts clouded the operations of too many of the brethren, there were notable exceptions to be found among these pioneers to a higher science, of whom Friar Bacon was a notable example; and his namesake, the Lord Chancellor of England, four centuries later suggested the method of interrogating nature by observation and experiment; and in the practice of these true modes of investigation, there in time arose from the furnaces and alembics a new philosophy that confounded all the reasoning of the ancients.

Putting aside Hermes Trismegistus, "the doctor of three parts of the wisdom of the world," also the Egyptian and scriptural authorities, the esoteric angels with naughty longings for Eve's fair daughters,

* The alchemist's laboratory comes down to us as "a gloomy, dimly. lighted place, full of strange vessels and furnaces and melting-pots, spheres, and portions of skeletons hanging from the ceiling; the stone floor littered with stone bottles, pans, charcoal, aludels and alembics, great parchment books covered with hieroglyphics ; the bellows with its motto Spira, Spera, the hourglass, the astrolabe, and over all cobwebs and dust and ashes. The walls covered with various aphorisms of the brotherhood, legends and memorials in many tongues, passages from the Smaragdine Table of Hermes Trismegistus, and looming out from all in great capitals ANAгKH."-("Birth of Chemistry," Nature, March 20, 1873).

Maria the Jewess, and other mythological entities, it may in part be confessed with Monsieur Dumas, the French chemist of our day, that "practical chemistry took its rise in the workshops of the smith, the potter, or the glass-blower, and in the shops of the perfumer, the first elements of scientific chemistry dating no further back than yesterday."

To the Hon. Robert Boyle, the first President of the Royal Society of London, the science of chemistry owes no small amount of obligation. He entered his protest against alchemistry, and raised valid objections to the introduction of morals and politics into philosophy. His experimental inquiries have ranked him among the first of the true chemists. He saw that metals increased in weight when calcined in the air, as had been surmised in the year 1630, by Rey of Perigord, and was cognisant of the air containing a principle which is consumed during respiration and combustion. Dr John Mayow, of Oxford, was a worthy contemporary of Boyle's, and had definite notions as to the combination of acids and alkalis; they and the inventive Robert Hooke, who was more of a philosopher than a chemist, contributed several papers to the Royal Society, the character of which rests mainly on the observation and the description of what has been called the qualitative side of phenomena, yet not without real value in building up

the science.

Sir Isaac Newton was more or less an alchemist, who spent days and nights in trying to discover the secret by which grosser metals might be changed into the more refined of gold or silver; but he failed, like the more ancient brethren in the art. His hypo

Van Helmont, Stahl, and Lavoisier.

13.

thetical and grandly deductive investigations found their real place and value in the walks of Natural. Philosophy all his tentative experiments in chemistry were but haphazard guesses recorded in his celebrated "Queries."

Among others of real note was Van Helmont, the mystic Belgian and psychologist, who helped to develop pneumatic chemistry by observing the properties of several elastic fluids, and who also described some of the qualities of the carbonic acid gas in the Grotto del Cane near Pozzuoli. But the most con

spicuous and able man of his time was Stahl, of Anspach, who propounded his phlogiston theory in 1697, possibly borrowed in part from Albertus Magnus, a theory that took well with the cultvators of chemistry early in the following century, and retained its grasp for upwards of a hundred years, checking in part the thoughts of Black, Cavendish, and Priestley, and for a time at least modifying the larger views of Lavoisier, and thus proving how tenaciously a doctrine once established will hold its own against the innovations of modern and more correct science.

The eighteenth century, that ushered in Stahl's theory with such force, happily provided chemistry with some of its most renowned cultivators and discoverers, notably Lavoisier, whose powers of generalisation cast the balance against the doctrines of combustion propounded by the learned Professor of Halle, and opened out fresh fields of inquiry of large interest and importance.

The Stahlian theory of phlogiston did service in its way, in laying hold of a common principle in facts

more or less analogous, e.g., those of combustion, calcination, and acidification, though it erred in attributing these processes to the dissipation of a peculiar ingredient. The new theory advanced by Lavoisier excluded the analogies, and offered an explanation more conformably to their nature, in the addition of the pervading element oxygen. This was the turning over of another page in chemical history, upon which was inscribed the freshest interest.

Chemistry was manifestly in the ascendant throughout the eighteenth century, and among the leaders of the science were Scheele, Black, Cavendish, Priestley, and Lavoisier; others of close secondary rank were Boerhaave, Bergman, Watt, Wenzel, Richter, and Higgins. A few words on some of the chiefs may be offered here, whilst a passing remark is due to Benjamin Franklin, the printer, for his revealing a new phase of electricity that excited the attention of the philosophic intellects of the world.

Charles William Scheele, the Swede, and pupil of Bergman, was an able analyst, who proved the character of several salts and gases, notably oxygen, without being aware of Priestley's earlier knowledge of the qualities of the gas. He discovered arseniate of copper, known as a pigment under the name of Scheele's green, and also succeeded in obtaining for the first time the active poison prussic acid in a separate form. Scheele justly ranks with his countrymen Linnæus and Berzelius, and the three constitute a trinity of eminence, in their respective walks, of whom the greatest nation in Europe might well be proud. The investigations of Dr Joseph Black of Edinburgh, as early as the year 1754, on the difference between

Black, Watt, and Cavendish.

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mild and caustic alkalis, have been regarded as the inauguration of the quantitative method in chemistry, and the first instance in which the nature of chemical combination and decomposition was clearly pointed out. These ideas were afterwards extended by Lavoisier to the whole range of chemical phenomena. About the year 1760 Black evolved the theory of latent heat, on which his scientific fame mainly rests, a theory from the practical application of which his pupil and assistant, James Watt, obtained a great success in his own line, the chemicodynamical-so great indeed, that it has revolutionised the mechanical powers of the world, and added a thousandfold to man's enterprise and superiority.

The most renowned man in science yet born to the aristocracy of England was the Hon. Henry Cavendish, nephew to the third Duke of Devonshire. He was educated at Cambridge, and devoted his whole life to scientific investigations; nay, shunning society and women, and all the pomps and vanities of the world, till philosophy marked him for her own. To him we owe much of the foundation of pneumatic chemistry. His discovery of hydrogen, and the radical difference between it and nitrogen, led to projects for aërial navigation or ballooning. He ascertained the composition of water from the union of two gases -oxygen and hydrogen—a discovery of greater importance than any single fact yet arrived at by human. ingenuity in the whole range of chemistry. He contributed to the Royal Society of London many papers on electricity, astronomy, and historical subjects. All his experiments and processes were of a most finished nature, displaying an accuracy and beauty