LEM 



LEM 



aspect, though near-sighted. He was in- 

 defatigably industrious to the end of his 

 life. He eat and drank little. Hunger 

 alone marked the time of his meals, and 

 his diet was plain and strong 1 . He had a 

 very good memory, and it is said, could 

 repeat the JEneid from beginning" to end. 

 'What he wanted to remember he wrote 

 down, and never read it afterwards. He 

 always professed the Lutheran religion ; 

 but he never went to sermons; and when 

 in his last sickness his favourite servant 

 desired to send for a minister, he would 

 not permit it, saying he had no occa- 

 sion for one. He was never married, 

 nor ever attempted it but once, when 

 he was about fifty years old ; and the 

 lady desiring time to consider of it, gave 

 him time to do the same : he used to 

 say, " that marriage was a good thing ; 

 but a wise man ought to consider of it all 

 his life." 



Leibnitz was author of a great multi- 

 tude of writings, several of which were 

 published separately, and many others in 

 the memoirs of different academies. He 

 invented a binary arithmetic, and many 

 other ingenious matters. His claim to 

 the invention of fluxions was the sub- 

 ject of much controversy, for which 

 the authors of the time may be consult- 

 ed. 



Hanschius collected with great care 

 every thing which Leibnitz had said in 

 different passages of his works on the 

 principles of philosophy ; and formed of 

 them a complete system, under the ti- 

 tle of " G. G. Leibnitzii Principia Phi- 

 losophise more geometrico demonstrata, 

 &c." 1728, in 4to. There came out u 

 collection of our Author's letters in 1734 

 and 1735, entitled " Epistolje ad diversos 

 theologici, juridici, medici, philosophici, 

 mathematici, historici, et philologici aug- 

 mentile MSS. auctores : cum annotation- 

 ibus suis primum divulgavit Christian 

 Cortholtus." But all his works were 

 collected and distributed into classes by 

 M. Dutens, and published at Geneva in 

 six large volumes, 4to., in 1768, entitled 

 " Gothofredi Gulielmi Leibnitzii Opera 

 Omnia, &c." 



LEMMA, in mathematics, denotes a 

 previous proposition, laid down in order to 

 clear the way for some following demon- 

 stration ; and prefixed either to theorems, 

 in order to render their demonstration 

 less perplexed and intricate, or to pro- 

 blems, to make their resolution more 

 easy and short. Thus, to prove a py- 

 ramid one-third of a prism, or parellelo- 

 piped, of the same base and height with 



it, the demonstration whereof, in the 

 ordinary way, is difficult and trouble- 

 some, tin's lemma may be premised, 

 which is proved in the rules of progres- 

 sion, that the sum of the series of the 

 squares, in numbers in arithmetical pro- 

 gression, beginning from 0, and going 

 on 1, 4, 9, 16, 25, 36, &.G., is always 

 subtriple of the sum of as many terms, 

 each equal to the greatest ; or is al- 

 ways one-third of the greatest term mul- 

 tiplied by the number of terms. Thus, 

 to find the inflection of a curve line, this 

 lemma is first premised, that a tangent 

 may be drawn to the given curve in a giv- 

 en point. 



LEMNA, in botany, a genus of the 

 Monoecia Diandria class and order. Na- 

 tural order of Miscellanea. Naiades, 

 Jussieu. Essential character : male, calyx 

 one-leafed ; corolla none : female, calyx 

 one-leafed; corolla none; style one; cap- 

 sule one-celled. There are 'six species. 

 These plants are well known by the name 

 of*' duck's meat," or "duck weed." They 

 are all annuals, and are found floating on 

 stagnant water. They are natives of most 

 parts of Europe, in ditches, ponds, &c. 

 LEMN1SCIA, in botany, a genus of the 

 Polyandria Monogynia class and order. 

 Essential character : calyx five-toothed ; 

 corolla five-petalled, recurved; nectary 

 cup-shaped, girding the germ ; pericar- 

 pium five-celled ; seeds solitary. There 

 is but one species, viz. L. guianensis. 

 The trunk of this tree is about twenty feet 

 in height, and one foot in diameter ; the 

 bark is brown and smooth ; the wood is 

 white and compact ; abundance of twist- 

 ed branches spread in every direction ; 

 leaves alternate, firm, and smooth ; flow- 

 ers at the ends of the shoot, very nume- 

 rous, in large corymbs, on a woody pe- 

 duncle : corolla ot a fine coral red. Na- 

 tive of Guiana. 



LEMON. See CITRUS. 

 LEMONS, salt of, used to remove 

 ink-stains from linen, is the native salt 

 of sorrel, the super-oxalate of potash. 

 The effect is produced by the oxalic 

 acid dissolving with facility the oxide of 

 iron in the ink, on the combination of 

 which with the tannin and gallic acid the 

 colour depends ; while, at the same 

 time, it can be used without any risk 

 of injury to the cloth, on which it has 

 no effect. See Ox A LATE. 



LEMONADE, a liquor prepared of wa- 

 ter, sugar, and lemon or citron juice. It 

 is very cooling and grateful. 



LEMUR, the nwcaitco, in natural histo- 

 ry, a genus of Mammalia, of the order 



