CLO 



CLO 



allied to BASALT, which see. It has re- 

 ceived its name from the sound which it 

 gives when struck. It occurs massive, 

 And forms beds, and sometimes assumes 

 the columnar form; its colour is grey, 

 with shades of green and yellow. Ics 

 specific gravity is 2.5, and it is composed 

 of x 



Silex .... 57.25 



Alumina . . . 23.5 



Oxide of iron . 2..25 



Manganese . . 25 



Soda .... 8.10 



Water . 3. 



Loss . 



9435 



5.65 



100 



CLINOPODIUM, in botany, a genus 

 of the Didynamia Gymnospermia class 

 and order. Natural order of Verticillatae. 

 Labiate, Jussieu. Essential character : 

 involucre many bristled under the whorl. 

 There are five species. 



CLIO, in natural history, a genus of 

 Vermes Mollusca ; body oblong, noyant, 

 generally sheathed, and furnished with 

 two dilated membranaceous arms or 

 wing-like processes? tentacula three, be- 

 sides two in the mouth. There are six 

 species. The C. retuso uses its arms or 

 wings, which are submembranaceous, like 

 a pair of oars. 



CLITORIA, in botany, a genus of the 

 Diadelphia Decandria class and order. 

 Natural order of Papilionaceae or Legu- 

 minoseae. Essential character: corolla 

 i nverted ; standard very large, spreading, 

 overshadowing the wings. There are 

 five species. 



CLITORIS. See ANATOMY. 



CLOCK, in horology, is a machine 

 which measures time with a degree of 

 accuracy that gives it a just preference 

 over the clepsydrx, and other methods 

 anciently used for the same purpose. 

 See CLEPSYDRA 



The sphere of Archimedes, made two 

 hundred years before the birth of Christ, 

 is usually considered as the first attempt 

 at the formation of a clock ; it had, indeed, 

 a maintaining power, but, being without 

 any kind of regulator, could only measure 

 time as a planetarium exhibits the motion 

 of the stars, with relative, but not with 

 positive precision. 



In 1232, a machine for measuring time 

 was sent by the Sultan of' Egypt to the 

 {'mperor Frederic II. but this, if it had 



any regulating part, most probably had 

 none superior to the flyer of a common 

 roasting jack. Wallingford, at the begin - 

 ing of the fourteenth century, and Dondi, 

 at the end of the same, have each had the 

 honour of being supposed the first inven- 

 tors of clocks; the account given of Don- 

 di's clock by Petrus Paulus Vergerius (in 

 Vit. Princip. Carrar. torn. 16.) makes it 

 nearly similar to our church clocks; as, 

 like them, it was placed on the upper part 

 of a turret, or steeple, and spontaneously 

 pointed out each of the twenty-four hours 

 in succession. There is still, however, 

 some doubt whether Dondi was the origi- 

 nal inventor. 



Boethius, at the end of the fifth century, 

 Pacificus, about the middle of the ninth, 

 and Gerbert, at the end of the tenth, are 

 also regarded as the inventors of clocks, 

 but on rather doubtful authority. 



There are many documents to prove 

 the- existence of clocks, with wheels and 

 weights, in the middle of the fourteenth 

 century, and therefore there is more rea- 

 son for assigning this period to the inven- 

 tion than any other. 



On comparing the various testimonies 

 relative to the origin of the clock, the fair- 

 est conclusion seems to be, that it is nei- 

 ther of so ancient a date as some writers 

 suppose, nor yet among those more recent 

 inventions which are placed in the last 

 two centuries; and that the first inventor 

 is not certainly known. 



The opinion of Fer. Berthoud, who has 

 written more on the subject of clock-work 

 than any other man, is evidently most just, 

 which asserts, that the clock is not the in- 

 vention of any one man, but an assemblage 

 of successive inventions, each of which is 

 worthy of a separate contriver.' 1 Wheel- 

 work which was known in the time of 

 Archimedes ; 2. the application of the 

 weight as a maintaining power; 3. .tie use 

 of the fly as a regulator ; 4. the. ratchet 

 wheel and click ; 5. the substitution of 

 the balance for the fly; and the escape- 

 ment, which was necessariv introduced 

 at the same time ; 6 the application of 

 the dial and hands : and 7. the addition 

 of the sinking part. 



In *he clock which was placed in a tow- 

 er <t the palace of Charles V. in 1364, 

 by Henry <le Wick, the reg'Uating part 

 consisted of a balance, which vibrated 

 backwards and forwards by an escape- 

 ment like that of common watches ; it 

 h.J no balance spring, but this deficien- 

 cy was :n some measric supplied by the 

 mode in wlucv. V. \\.is iuvV *o move ; its 

 arbor was vertical, and instead of resting 



