LYO 



LYR 



a manner as to counteract each other 

 with nearly equal effort, and render the 

 ship almost stationary with respect to 

 her head-way ; a ship is usually brought 

 to by laying either her main-top-sail 

 aback, the helm being put close down to 

 leeward. This is particularly practised 

 in a general engagement, when the hos- 

 tile fleets are drawn up in two lines of 

 battle opposite each other. It is also used 

 to wait for some other ship, either ap- 

 proaching or expected ; or to avoid pur- 

 suing a dangerous course, especially in 

 foggy weather, &,c. 



LYMPH, a fine fluid, separated in the 

 body from the mass of blood, and con- 

 tained in peculiar vessels. It is distin- 

 guished into watery and coagulable 

 lymph ; the former, as tears, for an exam- 

 ple, is little else than water holding in so- 

 lution a small portion of salt, and still less 

 of animal matter. Coagulable lymph, 

 which is found in the dropsy, contains a 

 very considerable portion of albumen, so 

 as to be viscid to the touch; and when 

 heated to coagulate firmly, like the white 

 of an egg. 



LYMPHATICS, or LTMPHEDUCTS, in 

 anatomy. See preceding article. 



LYONS (ISHAKL), a good mathemati- 

 cian and botanist, was the son of a Polish 

 Jew, silversmith, and teacher of Hebrew 

 at Cambridge, in England, where he was 

 come to scitle, and where young Lyons 

 was born, 1739. He was a very extraor- 

 dinary young man for parts and ingenui- 

 ty ; and showed very early in life a 'great 

 inclination to learning, particularly in ma- 

 thematics, on which account he was much 

 patronised by Dr. Smith, master of Trini- 

 ty College. About 1755 he began to 

 study botany, which he continued occa- 

 sionally till his death ; in which he made 

 a considerable progress, and could re- 

 member not only the Linn scan names of 

 almost all the English plants, but even 

 the synonyrna of the old botanists ; and 

 he had prepared large materials for a 

 Flora Cantabrigiensis, describing fully 

 every part of each plant from the speci- 

 men, without being obliged to consuL, or 

 being liable to be misled, by former au- 

 thors. 



In 1758, he obtained much celebrity, 

 by publishing " A Treatise on Fluxions," 

 dedicated to his patron Dr. SmitJi : and in 

 1763, " Fasciculus Plantarum circa Can- 

 tabrigiam," &c. In the same year, or the 

 year before, he read lectures on botany 

 at Oxford with great applause, to at least 

 sixty pupils ; but he could not be prevail- 

 ed on to make a long absence from Cam- 

 bridge. 

 VOL. IV, 



Mr. Lyons was some time employed as 

 one o*' the computers of the nautical al- 

 manac; and besides he received frequent 

 other presents from the Board of Longi- 

 tude for his own inventions. He had 

 studied the English history, and could 

 quote whole passages from the monkish 

 writers verbatim. He could read Latin 

 and French with ease, but wrote the for- 

 mer ill. He was appointed by the Board 

 of Longitude to sail with Captain Phipps, 

 in his voyage towards the north pole, 

 in 1773, as astronomical observator; and 

 he discharged that office to the satis- 

 faction of his employers. After his return 

 from this voyage he married, and settled 

 in London, where he died of the measles 

 in about two years. 



At the time of his death he was en- 

 gaged in preparing for the press a com- 

 plete edition of all the works of the late 

 learned Dr. Halley, a work very much 

 wanted. His calculations in " Spherical 

 Trigonometry abridged," w r ere printed 

 in the Philos. Trans, vol. Ixv. for the year 

 1775, page 470. After his death, his 

 name appeared in the title-page of a Geo- 

 graphical Dictionary, the astronomical 

 parts of which were said to be " taken 

 from the papers of the late Mr. Israel 

 Lyons of Cambridge, author of several 

 valuable mathematical productions, and 

 astronomer in Lord Mulgrave's voyage to 

 the northern hemisphere." The astrono- 

 mical and other mathematical calcula- 

 tions, printed in the account of Captain 

 Phipps's voyage towards the north pole, 

 mentioned above, were made by Mr. 

 Lyons. This appeared afterwards, by 

 the acknowledgment of Captain Phipps, 

 when Dr. Horsley detected a material er- 

 ror, in some part of them, in his " Re- 

 marks on the Observations made in the 

 late Voyage, &c." 1774. 



" The Scholar's Instructor, or Hebrew 

 Gra '.mar, by Israel Lyons, teacher of the 

 Hebrew tongue in the university of 

 Cambridge," the 2d edition, &c. 1757, 

 8vo. ; was the production of his father, 

 as was also another treatise, printed 

 at the Cambridge press, under the title 

 of *' Observations and Inquiries relating 

 to various parts of Scripture History, 

 1761. 



LYRE, a musical instrument of the 

 string kind, much used by the ancients. 

 From the lyre, which all agree to have 

 been the first instrument of the string 

 kind in Greece, arose an infinite number 

 of others, diiutring in shape and number 

 of strings, ai the psafterion, trigon, sam- 

 bucus,' pectis, magadis, burbiton, testudo, 

 (the two last are used promiscuously by 





