Mr Robison had suffered severely from the sea-scur vy, which prevailed to an extraordinary degree on board the Royal William. Out of 750 seamen, 286 were confined to their hammocks, and 140 scarcely able to walk on deck. From that circumstance, and many others, his dislike of the sea became very great, and he resolved to return to Glasgow to prosecute his theological studies, with the view of entering the. church. This resolution, however, was not carried in to effect. Mr. Robison received from Admiral Knowles a kind invitation to live with him in the country, and assist him in his experiments on ship-building and sea manship.
Mr Robison did not scruple to accept an invitation so congenial to his own studies; and in February, 1762, when Lieutenant Knowles was appointed to the Ven geance of 20 guns, be accompanied his pupil, and was extremely desirous of being appointed Purser to the ship. After visiting Lisbon, and other parts of Portu gal and Spain, he returned to England in June, and quitted the naval service. Before the end of the same year, Admiral Knowles, with whom he still resided, recommended him to Lord Anson, then the First Lord of the Admiralty, as a proper person to take charge of Harrison's Time-keeper, which, at the desire of the Board of Longitude, was about to be sent to the West Indies on a trial voyage. This eminent artist had com pleted his chronometer, " after having struggled," as Mr. Playfair remarks, "for 35 years against the physi cal difficulties of his undertaking, and the still more discouraging obstacles which the prejudice, the envy, and the indifference of his cotemporaries, seldom fail to plant in the way of an inventor." Mr. Robertson, of the naval school or Portsmouth, determined its rate and error on the 6th of November, and on the 26th of January Mr. Robison found it to indicate a difference of longitude of 5h 2' 47", which is only four seconds less than it was found to be by other methods. Mr. Robison and Mr. Harrison embarked a few days after wards on board the Merlin, which was sent to England with despatches for government. After a voyage mark ed by almost every species of naval distress short of ac tual shipwreck, the ship took fire, and it was with great difficulty that they reached Portsmouth on the 26th of March. On the 2d f April, the time of noon was found to be 1 lh 58' 61", instead of 12h, so that the whole error from the 6th of November till the 2d of April, was only 1' 531", which corresponds to about 20 miles of longitude.
Upon his return to England, Mr. Robison found Lord Anson afflicted with the illness of which he died, and his friend and patron, Admiral Knowles, disgusted with the admiralty and the ministry. His hopes of promotion depended only on his own personal services, and these were readily set aside at a period when Eng land derived no lustre from the virtues of her states men.
Under these circumstances, Mr. Robison resolved to return to Glasgow, with the view of qualifying himself for the church, and upon his arrival there, he devoted his whole attention to the study of the sciences. The example of his friend Dr. Black, who was about to give to the world his great discovery of latent heat, and of Mr. Watt, who was then bringing the steam-engine to perfection, stimulated him in his scientific career, and his constant intercourse with these great men, fostered that love of experimental and practical science which directed him in all his future researches.
In the year 1766, when Dr. Black was removed to the chemical chair in Edinburgh, he recommended Mr. Robison as his successor. He was accordingly elected for one year, and commenced his first course of lectures in October, 1766. In this situation Mr. Robison contin ued four years, but a new object now presented itself to his ambition. At the request of the Empress of Russia, Admiral Sir Charles Knowles was recommended to go to St. Petersburg, for the purpose of reforming and im proving the Russian navy. He engaged Mr. Robison to accompany him as his private secretary, with a salary of £250 per annum ; and they set sail from England in December, 1770.
In 1772, Mr. Robison was appointed Inspector-Gene ral of the corps of Marine Cadets at Cronstadt, with a salary double that of his predecessor, and the rank of Lieutenani•Colonel attached to It. This corps consist ed of about 400 Russian noblemen, who were educated by 40 masters and professors, and it was Mr. P,obison's duty to receive the reports of tl'e teachers, and to class the cadets in the order of their merit.
Upon the death of Dr. Russell in 1773, Principal Robertson, though not personally acquainted with our author, recommended hint to the vacant chair or natu ral philosophy in the University. The patrons or the University readily yielded to this recommendation, and as the Russian government offered to increase the salary and appointments of Mr. Robison, it was with some difficulty that he came to the resolution of settling in his native country, and of sitting in the next chair to Dr. Black. Finding it in vain to offer any farther inducement to detain himin Russia, the Empress gave him a pension of X80 per annum, accompanied with a request that he would take under his care two or three of the young cadets who were to be selected in suc cession. Mr. Robison left Cronstadt in June, 1774. He was admitted into the College on the 16th Septem ber, 1774, and delivered his first course of lectures in the tullowing winter. The system of mechani cal philosophy whiCh he taught, embraced dynamics, astronomy, mechanics, hydrodynamics, optics, elec tricity, and magnetism ; but he generally enlarged so much upon the early subjects of his lectures, that some of the last of these series were every year omit ted entirely in the course. When we consider that a great proportion of the students of this class are stu dents of divinity, from 15 to 17 years of age, who re quire a general knowledge of natural philosophy, it is not difficult to point out the nature of the course which should be pursued. Mr. Robison always supposed a degree of mathematical knowledge among his students which they never possessed, and even if they had gone through the requisite course, either at the University or with private masters, it by no means followed that they were able to bring this knowledge to bear in ful lcming a train of oral reasoning. In consequence of this, and of the small number of experiments which he introduced, and which he held as very subordinate parts of his lecture, his students, with the exception of a few, made very little progress in the physical sciences.