Henry Perigal: LMS Obituary

An obituary of Henry Perigal appears in an Appendix to Leonard James Rogers' paper 'On certain Regular Polygons in Modular Network', Proc. London Math. Soc. 29 (1) (1897), 706-735. The Appendix occupies pages 732 to 735.

Henry Perigal

Henry Perigal, who died on 6 June 1898, in the ninety-eighth year of his age, came of a family noted for their longevity. He traced his descent from Sigurd, a Dane, who, after a successful raid into Normandy, in 908, settled there and assumed the name of Perigal. He was in the tenth generation from Gideon Perigal, and his wife Madeline Duval, of Dieppe, who as Huguenots escaped from prison and settled in London. Mr Perigal's father, who reached the age of ninety-nine, was one of thirteen children, nine of whom reached a great age. Mr Perigal, who was born 1 April 1801, was the eldest of six, the youngest of whom, Mr Frederick Perigal, is now in his eighty-seventh year. As a result of the great age to which his father lived, he was "Henry Perigal, junior," till he was an old man himself. In early life he was a clerk in the Privy Council Office for a short time, and subsequently he held for many years a position in the office of Messrs Henry Tudor & Son, Stockbrokers, the senior partner of which firm was a personal friend of his. He was a member of the Astronomical, Microscopical, Meteorological, Photographic, and several other scientific Societies, and a very regular attendant at the meetings of all, usually staying to the end, and often being the last to leave; and it may be said that for thirty or forty years, during eight months of the year, he divided his time between daily office work at 29 Threadneedle Street and evening attendance at the meetings of scientific societies, the lectures at the Royal Institution, etc.

His connexion with the Meteorological Society was remarkable: the Society was founded in 1850; in May, 1853, he became Treasurer, and retained this office up his death - for forty-five years - signing cheques and attending to the financial business of the Society almost to the last. When our Society was formed he would have liked to join it at once, but feared that his paradoxical views on the subject of astronomical motions would disqualify him; he was much pleased therefore when, some years later, De Morgan offered to propose him as a member and signed his nomination form.

As a young man Mr Perigal was much interested in all kinds of lathe work, but especially in curve-tracing by means of Ibbetson's geometric chucks. To this subject he brought to bear great patience, perseverance, and delicacy of manipulation. Many of the curves so drawn by him between 1830 and 1840 are exquisite examples of fine geometrical tracings performed by means of the bow pen. He afterwards delineated mechanically a great number of bicircloidal curves, i.e., curves described by two circular motions. These curves were generated by a point moving uniformly round a circle the centre of which also moved uniformly round another circle. The curve traced depended upon the ratio of the angular velocities in these two circles, this ratio being fixed during the description of the same curve. He also devised little apparatuses, which he called kinescopes, for exhibiting' these curves to the eye as they were formed. The curve was traced by a bright point which, by a system of multiplying wheels, was made to move so rapidly as to exhibit a continuous bright line. He also occupied himself with curves generated by more than two circular motions, and as early as about 1835 had delineated the curves now generally known by the name of Lissajous, including the finite or retrogressive parabola, which he had obtained by points some years before he described it mechanically.

He also displayed great ingenuity in proving geometrical theorems by means of dissection and transposition of parts. These dissections were mostly discovered between 1830 and 1840. Among the best are his proof of Euclid i. 47, and his decomposition of a square into three squares. Unfortunately nearly all his work was published merely for private distribution among his friends, and, as he had not the pen of a ready writer (as he himself used to say), his diagrams were generally issued without sufficient explanation, and sometimes without any at all. These fugitive pieces, which were being produced by him for sixty years or more, are very numerous. They consist principally of diagrams of bicircloidal curves (some on large sheets), of the "Lissajous" curves, and of dissections. Some of the dissections he made as puzzles, forming them in card and wood, and gave to his friends. He also engraved them (as well as the finite parabola) upon some of his visiting cards. His proof of Euclid i. 47 was reproduced in Vol. ii. of the Messenger of Mathematics.

Mr Perigal's mechanical work in connexion with the lathe led him astray with respect to the motions of the moon and planets. As the Moon always turns the same face to the Earth, he considered that she should be regarded as subject to one simple circular motion, and not (as mathematicians said) to a motion of revolution round the Earth combined with one of rotation round her own axis. The point in dispute was not, as most people thought, merely a question of definitions, for Mr Perigal assumed as an axiom that a central force necessarily acted upon a body describing a circular orbit round it exactly as if the one was attached to the other by a rigid bar. The "Moon paradox" was afterwards taken up by Mr Jellinger Symons, and is frequently connected with his name. Mr Perigal made a great many mechanical devices to illustrate his views, and wrote a number of little tracts and fly-sheets, in prose and verse, on "Revolution and Rotation," the "Fallacy of the Moon's Rotation," &c. These were generally circulated privately, but some appeared in the Astronomical Register. He was almost unique as a paradoxer in being a persona grata wherever he went, and neither at our Society, nor at the Astronomical, did he ever bring forward his own views aggressively or in a manner that was objectionable to those who differed from him. He is included in the "Budget of Paradoxes"; but De Morgan lets him off very gently, saying that "he has published valuable diagrams in profusion," and that he was "entirely indebted to him for the illustrations of the article on 'Trochoidal Curves,' published in the Penny Cyclopaedia, without which the article would not have been written." There is no reason to doubt that he always believed that the "Perigalian system of Astronomy" would eventually supersede the Newtonian, but this did not interfere with his personal friendships with those who believed in a system which seemed to him obviously absurd. Mr Proctor's book on the Geometry of Cycloids was chiefly illustrated by blocks cut in the lathe by Mr Perigal; and Northcote in his work on The Lathe gives an illustration of the actual apparatus used, together with Perigal's rules for the use of Ibbetson's chucks. It may be mentioned that about 1868 Mr Perigal publicly offered a prize of £10 for the discovery of a curve (one of his own curves produced by circular motions) satisfying certain conditions. The prize was won by Clerk Maxwell, who obtained Mr Perigal's curve, and also by Mr W D Bushell. Many years ago he wrote a paper (in the Journal of the Society of Arts) on the way in which great monoliths, like those at Stonehenge, could be moved by such appliances as savages could use, and he also wrote upon the probable methods used in the construction of the Great Pyramid.

He was a warm friend, and a pleasant companion, gentle in manner, amiable, kind-hearted, and generous, interested in the topics of the day, and shrewd without being cynical. He rarely left London, and probably never went abroad in the last half of his life. At some time he had made a voyage to Madeira. Twenty years or more ago he let his beard grow, and since then his refined face, slight and fragile form, and long white beard and hair, made him a striking and picturesque figure. He ceased to attend scientific meetings two or three years ago, and for the last year or more had ceased to leave his lodgings; but there was no failure of mind or eye-sight. He was never married. By his own wish he was cremated at Woking.

Mr Perigal was elected a member of our Society, 23 January 1868, and was a frequent attendant at our meetings. There is a characteristic note by him, entitled "Link Trammels," in Vol. v., p. 144, in which he claims that Jopling had anticipated Peaucellier. The only other contribution he made was a verbal account of some "Geometrical Metamorphoses by Partition and Transformation" (8 January 1891). Many of these figures are to be seen in his pamphlet "Graphic Demonstrations of Geometric Problems," selected by H Perigal, which he presented to the members of the Association for the Improvement of Geometrical Teaching (1891), of which Association he was elected a member in 1874.

Dr Glaisher, in a note which accompanied the above account of his old friend, writes, "it was in 1855 that I first saw Perigal."

Last Updated March 2021