(Horace Benedict de) was born at Geneva in 1740. His father, an intelligent farmer, to whom we are indebted for some memoirs relating to rural economy, resided at Cenches, a place situated on the banks of the Arve, at the distance of half a league from Geneva; and this country life, added to an active education, expanded no doubt in young De Saussure that physical strength so necessary to the naturalist who devotes himself to travel. He repaired daily to town to enjoy the advantage of public instruction; and as he lived at the bottom of Salève, a mountain which he has since rendered celebrated, he amused himself frequently with ascending its steep and rugged sides. Being thus surrounded by the phenomena of nature, and at the same time aided by study, he conceived a taste for natural history, and avoided the error both of the learned, who form theories without having been out of their closets, and of those farmers who, living too near to Nature, are incapable of admiring her beauties.
His earliest passion was botany: a variegated soil, abundant in plants of different kinds, invites the inhabitant of the banks of the Leman to cultivate that agreeable science. This taste produced an intimacy between De Saussure and the great Haller. He paid him a visit in the year 1764, during his retreat to Bex; and he relates in his travels how much he admired that astonishing man, who excelled in every part of the natural sciences. De Saussure was induced also to study the vegetable kingdom, by his connection with Ch. Bonnet, who had married his aunt, and who soon set a just value on the rising talents of his nephew. Bonnet (See his life in this Suppl.) was then employed on the leaves of plants. De Saussure studied these organs of vegetables also, and he published the result of his researches under the title of Observations on the Back of Leaves. This small work, which appeared soon after the year 1765, contains new observations on the epidermis of leaves, and in particular on the milky glands by which they are covered.
About that period, the place of professor of philosophy falling vacant, it was conferred upon De Saussure, who was then only twenty-one years of age. Experience proves, that if premature rewards extinguish the zeal of those who labour merely for themselves, they, on the contrary, strengthen it in those who labour only for truth. At that time the two professors of philosophy at Geneva taught physics and logic alternately. De Saussure discharged this double task with equal success. He gave to his course of logic a practical end, and, as one may say, experimental turn; and his method of teaching, which began by studying the senses to arrive at the general laws of the understanding, announced already an able observer of nature.
Physics, however, were the part for which he had the greatest taste, and which conducted him to the study of chemistry and mineralogy. He then began his travels through the mountains; not now to examine their vegetable productions, but to study the mountains themselves, either in the florescence of which they are composed, or the disposition of their masses. Geology, a science which was then scarcely in existence, added charms to his numerous excursions through the Alps; and it was then that the talents of the great philosopher were really displayed. During the first fifteen or twenty years of his professorship, he employed himself by turns in discharging the duties of his office, and in traversing the different mountains in the neighbourhood of Geneva. He even extended his excursions on one side as far as the banks of the Rhine, and on the other to Piedmont. At the same time he undertook a journey to Auvergne to examine there the extinguished volcanoes, and another to Paris, England, and Holland. After that he visited Italy, and even Sicily. These were not mere journeys for the purpose of reaching any particular place; he undertook them only with a view of studying nature; never travelling but surrounded by every instrument that could be of use to him, and never yet put out until he had drawn up a plan of the experiments and observations he intended to make. He often says in his works that he had found this method exceedingly useful.
In the year 1779 he published the first volume of his Travels through the Alps; which contains a minute description of the environs of Geneva, and an excursion as far as Chamounix, a village at the bottom of Mont Blanc. Philosophers will read there with pleasure the description of his Magnetometer. The more he examined mountains, the more was he sensible of the importance of mineralogy. To study it with advantage, he learned the German language; and it may be felt, in the last volumes of his Travels, how much new mineralogical knowledge he had acquired.
Amidst his numerous excursions through the Alps, and at the time of the political troubles of Geneva in 1782, he found means to make his beautiful experiments on hygrometry, which he published in 1783, under the title of Effets sur Hygrométrie. This work, the best that ever came from his pen, established fully his reputation as a philosopher. We are indebted to him also for the invention of a new hygrometer. Deluc had had already invented his whalebone hygrometer; and on that account there arose between him and De Saussure a sort of contest, which degenerated into a pretty violent dispute.
In the year 1786 De Saussure resigned the professor's chair, which he had filled for about twenty-five years, to his pupil and fellow-labourer Piètet, who discharged with reputation the duties of an office rendered more difficult by succeeding to eminent a philosopher.
When De Saussure was invited by the state to take a share in the public education, he made it one of the subjects of his meditations, and presented the plan of a reform in the education of Geneva; the tendency of which was, to make young people early acquainted with the natural sciences and mathematics. He even wished that their physical education should not be neglected, and with that view proposed gymnastic exercises. This plan, which excited much attention in a city where every one is convinced of the importance of education, found admirers and partisans; but the poverty of its pecuniary resources was an obstacle to every important innovation. It was besides feared that, by altering established forms, they might lose the substance, and that things might be changed for the worse. The Genevese were attached to their old system of education; and they had reason to do so, because it had not only proved the means of diffusing knowledge generally amongst them, but had called forth the talents of several eminent mathematicians (a) and philosophers (b).
But De Saussure's attention was not confined to public education alone. He superintended himself the education of his two sons and a daughter, who have shewn themselves worthy of such an instructor. His daughter to the charms of her sex unites an extensive knowledge of the natural sciences; and his eldest son has already made himself known by his physical and chemical labours.
The second volume of his Travels was published in 1786. It contains a description of the Alps around Mont Blanc, which the author considers as a mineralogist, a geologist, and a philosopher. He gives also some interesting experiments on electricity, and a description of his electrometer, one of the most perfect that we have. We are indebted to him also for several instruments of measurement, such as his gyrometer, defined to measure the degree of the blueness of the heavens, which varies according to the elevation of the observer; his diaphanometer (See PHOTOMETER, in this Supplement), and his anemometer, which, by means of a kind of balance, measures the force of the wind.
Some years after the publication of the second volume of his Travels, De Saussure was admitted as a foreign associate of the Academy of Sciences of Paris; and Geneva could then boast of having two of its citizens in that class, which consisted only of seven members. De Saussure not only did honour to his country; he loved and served it. He was the founder of the Society of Arts, to which Geneva is indebted for the high state of prosperity it has attained within the last thirty years. He presided over that society till the last moment of his life; and one of his fondest wishes was the preservation of this useful establishment.
In consequence of M. de Saussure's fatiguing labours in the Council of Two Hundred, of which he was a member, and afterwards in the National Assembly, his health began to be deranged, and in 1794 he was almost deprived of the total use of his limbs by a stroke of the palsy. However painful his condition then might be, his mind still preferred its activity; and after that accident he revised the two last volumes of his Travels, which appeared in 1796. They contain an account of his excursions to the mountains of Piedmont and Switzerland, and in particular of his journey to the summit of Mont Blanc. These volumes, instead of exhibiting any marks of his malady, present an enormous mass of new facts and observations of the utmost importance to physics.
He rendered also an important service to that science by publishing the Agenda, which terminate his fourth volume, and in which that great man, surviving himself, conducts the young naturalist through the middle of mountains, and teaches him the method of observing them with advantage. These Agenda are a proof of his genius, and of the strength of mind which he retained amidst his sufferings. It was also during his illness that he directed the experiments made on the height of the bed of the Arve, and that he published Observations on the Fertility of Stones by the Blow-pipe, which were inserted in the Journal de Physique.
Having gone for the sake of his health to the baths of Plombières, he still observed the mountains at a distance, and caused to be brought to him specimens of the strata which he perceived in the fissured rocks. He had announced that he would conclude his travels with some ideas on the primitive state of the earth; but the more he acquired new facts, and the more he meditated on the subject, the more uncertain did his opinions become in regard to those grand revolutions which preceded the present epoch. In general he was a Neptunian; that is to say, ascribed all the revolutions of our globe to water. He admitted the possibility of the mountains having been thrown up by elastic fluids disengaged from the cavities of the earth.
Though the state of his health began gradually to become worse, he still entertained hopes of recovery; and the French government having appointed him professor of philosophy at the Special School of Paris, he did not despair of being one day able to fill that office; but his strength was exhausted, a general languor succeeded the vigour he had always enjoyed, his flow and embarrassed pronunciation no longer corresponded with the vivacity of his mind, and formed a melancholy contrast with the pleasantness by which he had been formerly distinguished. It was a painful spectacle to see this great man reduced thus to imbecility at an age when meditation is beneficial, and when he might have enjoyed the fruits of his reputation and labours.
In vain did he try, for the re-establishment of his health, all the remedies which medicine, enlightened by
(a) Absoult, Cramer, Lhuillier, J. Trembley, &c. (b) Jalbert, A. Trembley, Bonnet, Lefage, Deluc, Senebier, Prévost, Piètet, and De Saussure himself. the physical sciences, could afford— all assistance was useless. The vital power quitted him with slow and painful steps. Towards the beginning of autumn 1798 his decay became more visible, his mind lost all its activity, and on the 22d of March 1799 he terminated his brilliant career, at the age of 59, lamented by a family to whom he was dear—by a country to which he had done honour—and by Europe, the knowledge of which he had extended.