MAC 



MAC 



history of the progress which philosophy 

 had made before Newton's time ; and 

 this was the first draught of the work in 

 hand ; which not going forward, on ac- 

 count of Mr. Conduitt's death, was re- 

 turned to Mr. Maclaurin. To this he af- 

 erwards made great additions, and left it 

 in the state in which it now appears. His 

 main design seems to have been, to ex- 

 plain only those parts of Newton's philo- 

 sophy which have been controverted ; 

 and this is supposed to be the reason why 

 liis grand discoveries concerning light and 

 colours are but transiently and generally 

 touched upon ; for it is known, that when- 

 ever the experiments on which his doc- 

 trine of light and colours is founded had 

 been repeated with clue care, this doc- 

 trine hud not been contested; while 

 his accounting for the celestial mo- 

 tions, and the other great appearances 

 sf nature, from gravity, had been mis- 

 understood, and even attempted to be 

 ridiculed. 



MACQUER (JOSEPH), in biography, an 

 eminent chemist, was born at Paris in 

 1710. He was brought up to physic, and 

 became a doctor of the faculty of medi- 

 cine, in the university of Paris, professor 

 of pharmacy, and censor royal. He was 

 also a member of the academies of scien- 

 ces of Turin, Stockholm, and Paris, and 

 he held the medical and chemical depart- 

 ments in the Journal des Savans. M. 

 Macqvier made himself well known by 

 several useful and popular works on che- 

 mistry, of which science he was one of 

 the most successful cultivators on the 

 modern rational plan, before the new mo- 

 delling which it lias received of late 

 years. His publications were, " Elemens 

 de Chymie Pratique," two vols. 12mo. 

 1751-1756. " Plan d'un Cours de Chymie 

 experimentale etraisonnee," l!Jrno. 1757. 

 This was drawn up in conjunction with 

 M. Baum, who lectured on chemistry 

 in partnership with him ; " Dictionnaire 

 de Chymie," two vols. 8vo. 1766. These 

 works have been translated into English 

 and German : the dictionary, particularly, 

 by Mr. Keir, with great additions and 

 improvements. He wrote likewise " For- 

 mulae Medicament or um Magistralium," 

 1763 ; and " L'Art de la Teinture de 

 Soie," 1763 ; and he had a share in the 

 " Pharmacopeia Parisiensis," of 1758. 

 This meritorious writer died in 1784. 

 Diet. Hist, de la Med. par Eioy. Nouv. 

 Diet. Hist. 



MACROCEPHALUS, in natural his- 

 tory, a genus of insects of the order He- 

 miptcra: snout inflected; the sheath 



onc-valved, three jointed, and furnished 

 with three bristles ; antennae projecting, 

 very short, submoniliform, clavate ; head 

 oblong, cylindrical above ; scutel as long 

 as the abdomen, depressed, membranace- 

 ous. There is only one species, viz. M. 

 cimicoides, found in North America ; the 

 body is a ferruginous grey; scutel pale 

 ash with a yellow rigid spot ; under- 

 wings purplish violet ; fore-shanks thick- 

 ened. 



MACROCNEMUM, in botany, a genus 

 of the Pentandria Monogynia class and 

 order. Natural order of Contorts. Ru- 

 biacese, Jussieu. Essential character : co- 

 rolla bell-shaped; capsule two-celled, two 

 valved, with the valves gaping outwardly 

 at the sides ; seeds imbricate. There are 

 three species. 



MACROLOBIUM, in botany, a genus 

 of the Triandria Monogynia class and or- 

 der. Natural order of Lomentacece. Le- 

 guminosse, Jussieu. Essential character -. 

 calyx double, outer two-leaved, inner 

 one-leaved ; petals five, upper one very 

 large, the rest small, equal; germ pedi 

 celled, legume. There are three species, 

 all of them tall trees, from sixty to eighty 

 feet in height; they are natives of the 

 large forests of Guiana. 



MACROPUS, the kanguroo, in natural 

 history, a genus of mammalia of the order 

 Ferae. Generic character : six front teeth 

 in the upper jaw, emarginated ; two in 

 the lower, and very long, sharp, large, 

 and pointing forwards; five grinders on 

 each side of the upper and under jaw, 

 distant from the other teeth ; fore legs 

 very short ; hind ones very long ; the fe- 

 male with an abdominal pouch. This is 

 one of the most curious of all the animals 

 discovered on the continent of New 

 South Wales, where it was observed by 

 some of the sailors of Captain Cook in 

 the year 1770. When lull grown, it 

 weighs about 150 pounds. Its head 

 somewhat resembles that of a deer, but. 

 is destitute of horns; its countenance is 

 gentle and complacent; its colour is of a 

 pale brown ; its length from the nose to 

 the tail is between tour and live feet, and 

 the length of the tail is about three feet. 

 Its general position, when resting, is that, 

 of standing on its hind feet, on their 

 whole extent to the knees, and its fore 

 feet are frequently employed, like those 

 of the squirrel, as hands. The}' are often, 

 however, laid on the ground, and the 

 kanguroo is often seen in this posture, 

 feeding. Vegetables, and particularly 

 grass, constitute its only nourishment. 

 In its rapid motions, however, the fore 



