312 PHILOSOPHICAL TRANSACTIONS. [aNNO \66g. 



eR m the line of any case ; and of these, that which is written in the scheme 

 in the Hebrew manner, or from right to left, shows a motion contrary to the 

 other motion, which is denoted by the syllables written in the Latin way, or 

 from left to right. A syllable conjoined denotes the rest or quiescence of the 

 body. 



Calculation. ] 



R -\- S : S '.[ 2j : Ra 

 R + S:R:: Z: Sa 



I Re — 2Raz=:oR\\ So ^2Sa = e S. 

 \aSa± Se zzzoSpRa-^- Ro = eR. 



Nature observes the rules of specious (algebraical) addition and subtraction. 



Jn Account of two Books. A^" 43, p. 868. 



I. Historia Coelestis ; Ex Libris et Commentariis MSS. Observationum 

 Vicennalium Tychonis Brahe,* Dani, Augustae Vindelic. An. l666, in folio. 



* Tycho Brahe was a celebrated Danish astronomer, in the 1 6th century, and famous for having 

 given name to a new, though erroneous, system of the planets. Tycho was born, of a noble family, 

 in 1546, and having studied Latin, from 7 to 12 years of age, under private tutors at home, he was 

 then sent to study philosophy and rhetoric at Copenhagen. While there, the great solar eclipse, 

 Aug. 21, 1560, happening at tlie precise time it had been foretold by tlie astronomers, he began to 

 consider astronomy as something divine, and from tliat time devoted his attention chiefly to die ce- 

 lestial science, purchasing and privately studying every book relating to it tliat he could procure. 

 After four years stay at Copenhagen, he was sent, in 1562, to Leipsic to study tlie law, where his 

 acquirements gave clear indications of extraordinary abilities : taking every occasion however of im- 

 proving his astronomical knowledge ; and having there procured a small celestial globe, he took op- 

 portunities, when his tutor was in bed, to examine the constellations m the heavens, learning their 

 names from the globe, and their motions from observation. After a course of three years study at 

 Leipsic, he returned home, in 1565j in which year, being of an irritable temper, a quarrel arose 

 between him and a Danish nobleman, when they fought, and by a stroke of a sword Tycho lost 

 great part of his nose 3 which he ever after supplied so well by a substitute of precious metal and 

 wax, that it was not perceived. About this time he began to apply to chemistry, proposing notliing 

 less than to obtain the philosopher's stone. But becoming disgusted to see his favourite objects of 

 study despised, he left his country and resided some years in different parts of Germany. In 1571 

 he returned to Denmark : and was favoured by his maternal uncle, Steno Billes, a lover of learning, 

 with convenient accommodations at his castle for making his observations, and building a laborator}% 

 And here it was that he discovered, in 1573, a new star in the constellation Cassiopeia, But soon 

 after, marrying a country girl, beneath his rank, it occasioned such a quarrel between Tycho and his 

 relations, that the king was obliged to interpose to reconcile them. In 1574, by the king's order, 

 he read lectures at Copenhagen on the theory of tlie planets. Soon after tliis he again travelled 

 through Germany, and had thoughts of removing his family and settling at Basil : but tlie king, 

 Frederick II. vmwilling to lose a man capable of doing so much honour to his country, promised 

 to enable him to pursue his studies to his satisfaction, and bestowed on him for life tlie island of 

 Huen in the Sound, ordering an obsen'atory and laboratory to be built for him there, with a supply 

 of money for carrying on his designs. Accordingly the observatory was founded in 1576, under the 

 name of Uranibourg, with an ample pension from the king. This situation Tycho enjoyed for about 

 20 years, pursuing his observations and studies with great diligence ; keeping always about him ten 

 or twelve young men, who assisted him in his -observations, and whom he instructed in astronomy 



