Although Mr. Robison's lectures had thus an unpo pular aspect, yet they were listened to with delight by those who had devoted their minds to the subject t and who now consider themselves fortunate in having at tended the University, when he had health enough to go through the labours tirtrZ.: course. Dr. Robison never condescended to become a dealer in scientific shows, to amuse his students with the exhibition of trifling instruments and experiments, fit only for the nursery, to occupy their time with conceits and extra vagancies of his own ; to falsify the history of science for the purpose of elevating himself, or to sneer at those venerable men whose names have been consecrated by time, and those revered opinions which have com manded the assent of the wisest as well as the best ages of the world. Like his eminent successor in the chair, Professor Mayfair, his great object was to instruct his students in the sciences, to give just and candid esti mates of the labours of others, and to impress upon the minds of the young those great lessons of humility and piety, which the study of the material world is so well calculated to teach.
Soon after his return from Russia, Mr. Robison be came a member of the Philosophical Society, which had existed since 1739. When it was incorporated with the Royal Society, which was established in 1781, Mr. Ro bison was appointed general secretary, and continued to discharge the duties of that office till the state of his health compelled him to resign.
It is a curious circumstance, that Professor Robison never appeared as an author, till the year 1786, when, in the 47th year of his age, he published in the Trans actions of the Royal Society of Edinburgh, A determina tion of the orbit and the motion of the Georgium Sidus, directly from observation. The elements of the orbit of this planet, though deduced from observations made with an instrument fixed from a window, du not differ widely front those which have more recently been ob tained from more numerous observations, and by means of better instruments.
The second, and the only other paper which Profes sor Robison communicated to the Royal Society of Edinburgh, was read on the 7th April, 1788, and is en titled, On the Motion of Light, as affected by Refract ing and Reflecting Substances, which are also in motion, and relates principally to the correction of some errors of Boscovich respecting the effects of a telescope, the tube of which is filled with water instead of air, upon the aberration of light. The celebrated Italian philoso pher had rashly announced that if a water telescope were directed to a terrestrial object properly situated, it will deviate from that object by a certain determi nate quantity every day; but Professor Robison has shown that this result is not deducible from Boscovich's own principles.
This paper was drawn up when Mr. Robison was in very bad health; and for the purpose, as he remarks, " of ascertaining his claims to any thing which may be valuable in his speculations." He had been attacked, in December, 1785, with a severe disorder, which baf fled all the skill of his medical friends, and which, though it did not materially injure his general health, continued to aglict him doting the rest of his life.
Notwithstanding this indisposition, he engaged, about the year 1793, to contribute various scientific articles to the edition or the Encyclopedia Britannica, which was then publishing. This work never had been under the charge of any literary or scientific man, till it came un der the management of Dr. Gleig; and therefore the aid of such an editor and of such a contributor as Dr. Robi son, formed an era in its history. Dr. Robison revised and enlarged the article Optics, which was followed by the article Philosophy, which he wrote jointly with Dr. Gleig. His own articles are, Physics, Pneumatics, Pre cession, Projectiles, Pumps, Resistance, Rivers, Roof, Ropenzaking, Rotation, Seamanship, Signal, Sound, Spe qfic Gravity, Statics, Steam, Steam-Engine, Steelyard, Strength of Materials, Telescope, Tide, Trumpet, Varia tion, and Waterworks. In, a bound copy of Mr. Robi son's articles, labelled with his own hand, and now be fore us, we find the articles Perspective, Plough, and Russia, which it is probable he also wrote.
A supplement to the third edition of the Encyclopedia Britannica was published some time afterwards by dif fierent proprietors, and to this work 'Mr. Robison cont•i buted the following articles : Arch, Astronomy, Bosco vich's Theory, Carpentry, Centre, Dynamics, Electricity, Impulsion, Involution, Machinery, Magnetism, Mecha nics, Percussion, Piano-Forte, Position, Temperament, Thunder, Trumpet, Tschirnhaus, and Watchwork.
" To those who may examine," says Dr. Brewster, in his preface to Dr. Robison's System of illechanical Philosohhy," these dissertations with a critical eye, it may be necessary to state, that they were composed un der the influence of that painful disease, with which he was afflicted for a long period of years. The knowledge of mechanical philosophy which they every where dis play, possesses the rare quality of being at once practi gal and profound ; and they are often enriched with original views, and ingenious inventions, which it re quired only the tranquillity of health to perfect and mature. It was his destiny, however, to enjoy but at distant intervals that calm of mind which can alone sustain the ardour of discovery. At such periods his ambition constantly reverted to those original pursuits which he was desirous of bringing to a close; but they were no sooner begun than they were interrupted by renewed attacks of that disease which ultimately de prived him of his life." To these observations it may be added, that as Dr. Robison had no scientific articles of any value to refer to in the previous part of the work, he was obliged to introduce preliminary discussions as portions of the treatise which he was writing, and from this cause the articles arc destitute of that symmetry and method which would otherwise have characterized them.