MAR 



MAS 



eians of his time. He first taught a school 

 in the country ; but afterwards came up 

 to London, were lie read lectures on ex- 

 perimental philosophy for many years, 

 and carried on a very extensive trade as 

 an optician and globe-maker in Fleet- 

 street, till the growing infirmities of old 

 age compelled him to withdraw from the 

 iictive part of business. Trusting too fa- 

 tally to what he thought the integrity of 

 others, lie unfortunately, though with a 

 capital more than sufficient to pay all his 

 debts, became a bankrupt. The unhap- 

 py old man, in a moment of desperation 

 from this unexpected stroke, attempted 

 to destroy himself ; and the wound, 

 though not immediately mortal, hastened 

 his death, which happened the 9th of Feb. 

 ruary, 1782, at 78 years of age. 



He had a valuable collection of fossils 

 and curiosities of almost every species ; 

 which, after his death, were almost given 

 away by public auction. He was indefa- 

 tigable as an artist, and as a writer he had 

 a very happy method of explaining his sub- 

 ject, and wrote with clearness, and even 

 considerable elegance. He was chiefly 

 eminent in the science of optics ; but he 

 was well skilled in the whole circle of the 

 mathematical and philosophical sciences, 

 and wrote useful books on every one of 

 them ; though he was not distinguished 

 by any remarkable inventions or discove- 

 ries of his own. His publications were 

 very numerous, and generally useful ; 

 some of the principal of them were as fol- 

 lows : 



" The Philosophical Grammar; being 

 a View of the present State of Experimen- 

 tal Physiology, or Natural Philosophy," 

 1735, 8vo. " A New, Complete, and Uni- 

 versal System or Body of Decimal Arith- 

 metic," 1735, 8vo. "The Young Student's 

 Memorial Book, or Pocket Library," 

 1735, 8vo. " Description and Use of both 

 the Globes, the Armillary Sphere, and 

 Orrery, Trigonometry," 1736, 2 vols. 8vo. 

 " System of the Newtonian Philosophy," 

 1759, 3 vols. " New Elements of Op- 

 tics," 1759. " Mathematical Institutions," 

 1764, 2 vols. " Philologic and Philoso- 

 phical Geography," 1759. " Lives of 

 Philosophers, their Inventions, &c." 1764, 

 3 vols. " Miscellaneous Correspondence," 

 1764, 4 vols. " Institutions of Astronomical 

 Calculation," 3 parts, 1765. Introduction 

 to the Newtonian Philosophy," 1765. 

 ' Treatise of Logarithms." " Treatise on 

 Navigation." " Description and Use of 

 the Air-pump." " Description of the 

 Torricellian Barometer." " Appendix to 

 the Use of the Globes." Philosophia Bri- 



tannica," 3 vols. Principles of Pump- 

 work." " Theory of the Hydrometer." 

 " Description and Use of a Case of Ma. 

 thematical Instruments" " Ditto of a 

 universal Sliding Rule." " Micogniphia, 

 or the Microscope" '* Principles of 

 Perspective." " Course of Lectures." 

 " Optical Essays " " Essay on Electrici- 

 ty." ** Essay on Visual Glasses, or Spec- 

 tacles." " Horologia Nova, or New Art 

 of Dialling." " Theory of Comets." "Na- 

 ture and Construction of Solar Eclipses." 

 " Venus in the Sun." " The Mariner's 

 Mirror." " Thermometrum Maguum." 

 " Survey of the Solar System." " Essay 

 on Island Crystal." * Logorithmologia 

 Nova," &c. &c. 



MARTYN1A, in botany, so named in 

 honour of John Martyn, F. R. S. profes- 

 sor of botany at Cambridge, a genus of 

 the Didynamia Angiospermia class and 

 order. Natural order of Personate. 

 Bignonise, Jussieu. Essential character: 

 calyx five cleft ; corolla ringent ; capsule 

 woody, corticate, with a hooked beak, 

 four-celled, two-valved. There are six 

 species, 



MARTLETS, in heraldy, little birds 

 represented without feet, and used as a 

 difference or mark of distinction for young- 

 er brothers, to put them in mind that they 

 are to trust to the wings of virtue and 

 merit in order to raise themselves, and 

 not to their feet, they having little land to 

 set their foot on. 



MASON, a person employed under the 

 direction of an architect in the raising of 

 a stone building. The chief business of 

 a mason is to make the mortar ; raise the 

 walls from the foundation to the top, with 

 the necessary retreats and perpendicu- 

 lars ; to form the vaults, and employ the 

 stones as delivered to him. When the 

 stones are large, the business of hewing- 

 or cutting them belongs to the stone-cut- 

 ters, though these are frequently con- 

 founded with masons : the ornaments of 

 sculpture are performed by carvers in 

 stones, or sculptors. The tools or im- 

 plements principally used by them are 

 the square, level, plumb-line, bevel, com- 

 pass, hammer, chissel, mallet, saw, trow- 

 el, &c. Besides the common instruments 

 used in the hand, they have likewise ma- 

 chines for raising of great burdens, and 

 the conducting of large stones, the prin- 

 cipal of which are the lever, pulley, wheel 

 and axis, crane, &c. See LEVER, &c. 



MASONS, free and accepted, a very an- 

 cient society or body of men, so called, 

 either from some extraordinary know- 

 ledge of mason ny or building-, which they 



