CHARLES MARIE DE LA, a practical geographer and cultivator of science in general, son of Charles de la Condamine, a receiver-general of finances, and Margaret Louise de Chources, was born Jan. 28, 1701.
His early education was by no means neglected, although he complains that he was made to learn too much by rote, without understanding the complete sense and bearing of the words which he repeated. He afterwards pursued his studies under Father Brisson; and in 1717 he supported a thesis on the Cartesian philosophy, which the Jesuits were then beginning to introduce into their seminaries. In 1719 he entered the army, and accompanied his uncle, the Chevalier de Chources, to the siege of Rossas, as a volunteer; and both on this and other occasions he exhibited proofs of the contempt of danger and the spirit of enterprise which were so much required in those pursuits that afterwards occupied a considerable portion of his life. Unlike most young men of his time, he was moderate in the pursuit of pleasure, and used to consider the disfigurement which the smallpox had left in his features as affording him some compensation for the injury done to his vanity, by diminishing the temptations to which he might otherwise have been exposed.
Having no prospect of speedy advancement in the army, and having suffered considerably in his fortune from a participation in the extravagant speculations of Law, he quitted the service, in hopes of finding a more advantageous employment in scientific pursuits. He distinguished himself as an active member of a society of arts, then recently established at Paris by the Count de Clermont; and in 1730 he obtained a situation in the Academy of Sciences, as adjunct of the class of chemistry, having previously presented to the academy a memoir on the mathematical and mechanical properties of the lathe, which obtained him considerable credit. Soon afterwards he embarked in the squadron of Duguay Trouin, and made a voyage in different parts of the Mediterranean. He passed several months at Constantinople, and visited the plain of Troy, and many other parts of the Levant; and after his return he gave an account of his tour to the academy. His servant, too, who had accompanied him, published a separate journal of his own.
Chemistry, as cultivated at that period, afforded but little scope for the employment of an active mind; and La Condamine, after the publication of one chemical memoir only, was removed from the class of chemists in the academy to that of astronomers. In this capacity he was the first to propose the measurement of a degree of latitude in the neighbourhood of the equator. His ideas were readily seconded by Maurepas, then prime minister; and he was appointed by the academy, together with Bouguer and Godin, for carrying the proposal into effect.
In this expedition he was absent from 1735 to 1745; and had to encounter difficulties of every kind. A long series of dangers and disasters, to say nothing of the awful appearance of an eruption of Cotopaxi, and the no less formidable operations of the hostile squadron of Lord Anson, required nothing less than the dauntless spirit and energy of character which he possessed to bear him up against them; and at last the little jealousies, which will often arise among persons of science employed in the same pursuits, embarrassed and embittered the conclusion of his enterprise. The activity and fluency of La Condamine made the public disposed to imagine that Bouguer had been only his humble attendant; and Bouguer was too conscious of his own superiority as a mathematician to bear this injustice with patience. He retaliated by refusing all communication in the statement of the results of the operations; so that each observer gave ultimately a separate account of his own measurements and calculations.
In consequence of the fatigues and vicissitudes to which La Condamine had been exposed, he became extremely deaf, and partially paralytic; but the powers of his mind appear to have remained unimpaired.
In 1748 he was elected a foreign member of the Royal Society of London; and he afterwards exerted himself with great zeal and success in promoting among his countrymen the general introduction of the variolous inoculation, which had long been practised in England and elsewhere. In 1757 he visited Italy, and spent a considerable time at Rome, principally, it would appear, in order to obtain a dispensation from the pope for a marriage with his niece, who seems, notwithstanding the disparity of their ages, and his capricious and irritable temper, to have been sincerely attached to him. In 1760 he became one of the forty members of the French Academy, and contributed considerably to an improved edition of their dictionary. In 1763 he paid a visit to England, which was rendered less agreeable to him from the difficulty that he found in obtaining legal redress for some slight injury he had received. After his return, the insensibility of his limbs increased, and he was obliged to relinquish all his pursuits of science, retaining only the amusement of making some light attempts in poetry, and occasionally inserting in the periodical works of the day a few tales in verse, besides a poetical translation of a part of Virgil's *Ennius*.
His first publication was a *Memoir on the Comic Sections*, M. Ac. Par. 1731, p. 240. It contains a comparison of the equations of the various parallel sections of a given cone with that of the surface of the cone itself; but it is not distinguished either for clearness of conception or for accuracy of expression.
2. *On Metallic Vegetation*, M. Ac. Par. 1731, p. 466, H. P. 31. The experiments described in this paper relate to the precipitation of nitrate of silver, or other metallic solutions placed upon a flat surface of glass or agate, by means of an iron nail.
3. *Observations made in the Levant*, M. Ac. Par. 1732, p. 295; relating principally to navigation, geography, and natural history.
4. *Account of an Instrument for determining a Parallel Circle on the Earth's Surface*, M. Ac. Par. 1733, p. 294, H. P. 53; a telescope fixed perpendicularly on an axis parallel to that of the earth, and consequently capable of being directed only to objects situated in the parallel circle required, proper allowance being made for the effects of refraction.
5. *Description of a Variation Compass*, M. Ac. Par. 1733, p. 446. A wire is fixed in the axis of the card, and a graduated ring of paper round its circumference, half above and half below, on which the shadow of the wire is to fall at sunset.
6. *Two Memoirs on the Lath*, M. Ac. Par. 1734, pp. 216, 295. A description of the rosette and of other parts of the figure lath, with a mathematical determination of the epicycloids, conchoids, and other curves, which are traced by their combination. The apparatus is represented among the machines approved by the Academy, vol. v. pp. 83, 89.
7. *A Letter relating to the Variation Compass*, M. Ac. Par. 1734, p. 597.
8. *On the Determination of small Differences of Longitude*, M. Ac. Par. 1735, p. 1; a discussion of the kinds of signals best adapted for contemporaneous observations at a distance.
9. *Measurement of the Length of the Pendulum at St Domingo*, M. Ac. Par. 1735, p. 529. See Cohesion.
10. *Account of the Quinquina Tree*, M. Ac. Par. 1738, p. 226.
11. *Abstract of a Journey through a part of South America*, M. Ac. Par. 1745, p. 391, H. 63.
12. *Abstract of the Geographical Operations performed in South America*, M. Ac. Par. 1746, p. 618. The length of a degree at the equator appears, from these calculations, to be 56,750 toises. Bouguer, who employs the same determination of the arc, but a different series of trigonometrical observations, makes it 56,753; and Godin, on the other hand, somewhat less than Condamine. This is more than 300 toises less than the degree measured in France, and almost 700 less than the degree in Lapland; and it gives for the earth's ellipticity, by comparison with the former, $\frac{1}{2}$, and with the latter $\frac{1}{2}$. The terminations of the base were marked by pyramids, and the length of the toise was identified by a bar of metal let into a tablet of marble.
13. *Mesure des Trois premiers Degrés du Méridien*, 4. Par. 1751, with a complete journal of the operations.
14. *A Proposal for an Invariable Standard of Measures*, M. Ac. Par. 1747, p. 489, H. P. 82.
15. *Account of an Elastic Resin*, M. Ac. Par. 1751, p. 319, H. P. 17; a description of several trees affording the cauchou, or caoutchouc, especially of the Hheve, or syringe trees.
16. *A History of the Variolous Inoculation*, M. Ac. Par. 1754, p. 615; a candid and judicious statement of the advantages of the inoculated above the natural smallpox, in a style calculated to meet the prejudices of the day, and the various superstitions and interested motives which retarded the practice in France, while it had become universally prevalent in England; although, in more recent times, the public spirit in this country appears to have been less favourably disposed to the admission of beneficial innovations; for it is well known how strenuously an interested or ignorant opposition was organized against the practice of vaccination.
17. *Abstract of a Journey in Italy*, M. Ac. Par. 1757, p. 336, H. P. 6. From an examination of several ancient standards, and from a comparison of the remains of buildings supposed to have occupied a certain round number of feet, M. de la Condamine concludes that the old Roman foot was equal to 1309 French lines; that is, to 969 thousandths of an English foot. Mr Folkes had before made it 965; but Mr Raper has shown, in the Philosophical Transactions for 1760, by a very careful comparison of a multitude of documents, that before the reign of Titus it somewhat exceeded 970, and under Severus and Diocletian it was less than 965; the original standard in the temple of Juno Moneta having probably been destroyed by fire. M. de la Condamine also viewed the races on the Corso with an eye equally mathematical, and observed that the Barbary horses ran at the rate of about forty English feet in a second; but his correspondents in England furnished him with unexceptionable evidence that the horse *Childers* ran the four-mile course at Newmarket at the rate of very nearly fifty English feet in a second, while no other horse exceeded forty-eight; and he observes that, in this instance, truth far outruns probability; a remark which has been somewhat misrepresented in this country, and converted, by the lovers of the amusements of the turf, into a laugh against the lovers of the amusements of science; the story being told as if the French mathematicians had demonstrated the absolute maximum of a horse's utmost possible speed, and, a bet having been made on the occasion, an English horse had been found that actually exceeded the maximum. Our author also notices the awkward effect of the Roman mode of beginning the day at sunset, which renders it necessary to make continual alterations in the clocks—directions being given in the almanacks for putting them forwards or backwards a quarter of an hour at a time; and the precise time of noon happening in summer at sixteen o'clock, and in winter not till nineteen. He observes that a single signal, properly placed on the Apennines, would be visible at once near Trieste and near Monaco, giving a difference of longitude of not less than five degrees.
18, 19. On Inoculation, M. Ac. Par. 1758, p. 439; 1765, p. 505.
20, 21. M. de la Condamine published also a series of Lettres sur les Dictionnaires, and another of Lettres sur l'Éducation.
In 1768 his name is mentioned as having excited the attention of the members of the academy by a relation of Spallanzani's experiments on the reproduction of the heads of snails, which several of them repeated with success. In fact, there was scarcely any one of the sciences to which he did not occasionally render some service, although he wanted patience and perseverance to make any very important discoveries or improvements by his individual exertions only. But his knowledge was universal; he understood and wrote all languages; corresponded with men of celebrity in all countries; published upon all subjects; contributed to all the literary and scientific journals of the day; answered all criticism, and accepted all compliments, even from persons whom he despised; for he delighted in the parade of a pre-eminent reputation. His style was simple and natural, somewhat negligent, but still elegant and lively; his manner was animated and somewhat singular; his temper warm and restless; he sighed for repose, and was incapable of enjoying it; thinking nothing that occurred indifferent to him, and allowing none about him to be idle.
He obtained the rank of chevalier in several orders, and was a member of several foreign academies. He held also the appointment of honorary secretary to the Duke of Orleans. At the age of sixty-eight he addressed to his wife an account of his education, and of the earlier progress of his mental faculties, as a practical illustration of his opinions respecting the cultivation of the mind. The memoir was not published. A few years before his death he printed a memorial in behalf of M. Godin, who had been reduced to indigence; and he had the pleasure of obtaining for him the assistance which he required. He suffered occasionally from a hernia; and having read of the marvellous cures which some empiric professed to have performed by the application of caustic, he made the experiment on himself, without the knowledge of his family, and fell a victim to his temerity. In the course of the six weeks that he survived, he was still employed in writing or dictating a memoir containing answers to some questions respecting the manners of the Americans. He died Feb. 4, 1774, leaving many of his books and instruments by will to the Academy of Sciences. (Hist. Acad. Par. 1774, p. 85.)