312 Intelligence and Miscellaneous Articles. 



a yellow colour, and finish by rendering it black ; when heated to 

 ebullition, it blackens immediately. It is formed of 2 atoms of 

 sulphuret of mercury, and 1 atom of anhydrous neutral nitrate of 

 mercury. The solution of cyanide of mercury is an exception to 

 the general rule: in this, the smallest quantity of sulphuretted hy- 

 drogen occasions the formation of black sulphuret of mercury. — 

 Hensman's Repertoire, Nov. 1828. 



PROFESSOR BESSEL S PENDULUM EXPERIMENTS. 

 Professor Bessel has lately published the First Part of his Pendu- 

 lum Experiments, which contains the investigation of the length of 

 the pendulum at Koenigsberg. We shall probably lay before our 

 readers in a future Number of this Journal, either a translation or 

 an abstract of this most interesting and important publication. In 

 the mean time we communicate the final results which Prof. B. has 

 obtained : 



Length of the seconds pendulum in 1 . . ^'?f!. ►, ^ r> • 



.,* r^, , cj^ • u > MO-SHY 1 Pans measure 



the Observatory of Koenigsberg. . j v. h tl t ' 



The same reduced to the level of] . . „ r> i «« i c -o 

 theBaltic J440-8179J ot Peru. 



SCIENTIFIC BOOKS. 

 Just published. 

 Principles of Natural Philosophy ; or a New Theory of Physics, 

 founded on Gravitation, and applied in explaining the general pro- 

 perties of Matter, the Phaenomena of Chemistry, Electricity, Gal- 

 vanism, Magnetism, and Electro-Magnetism. By Thomas Exley, 

 A.M. Associate of the Bristol Philosophical and Literary Society. 



Preparingjbr Publication. 



The British Merchant's Assistant. — Part I. Tables of Simple In- 

 terest, at 3, 3i, 4, 4^, and 5 per cent, calculated from 1 to 365 

 days, from 1 to 12 months, and from 1 to 14 years ; on amounts 

 from £1 to £20,000. 



Part II. Tables for computing the premium and discount on 

 Exchequer Bills and India Bonds j also the Interest on Exchequer 

 Bills, at i^d. l^d. "zd. ^Id. 2|rf. 2|rf. id. 2>ld. and 3\d. per cent, 

 per diem, from 1 to 365 days ; on amounts from £100 to £20,000. 



Part III. Tables for ascertaining the value of every description 

 of English and Foreign Stock at any given price from Is. to £100 

 percent, on amounts from Id. to £20,000. Also Tables for cal- 

 culating Brokerage, Commission, Freight and Insurance at every 

 rate per cent. To which are added, Tables showing the number 

 of days from the 1st of each month to every other day in the en- 

 suing year: — the amount of Interest due to the holder of £100 

 British Stock, at the rates of 3, 3^, 4, 4|, and 5 per cent, for every 

 day, from the receipt of one dividendjuntil the payment of the uext. 



The whole constructed on a more extended scale than any simi- 

 lar Tables hitherto published, and airanged in a novel and perspi- 

 cuous manner. By G, Green. In one large volume; price to Sub- 

 scribers, £1 lis. 6rf. ' Restdts 



