182G.] [ 519 ] 



PHILOSOPHICAL, CHEMICAL, AND SCIENTIFIC MISCELLANIES. 



Ekctro-chemical means of preserving 

 Metal. — In addition to tlie use of" proserv- 

 ing tiie copper sheathing of sliips, Sir II. 

 Davy suggests the ap|)Iieation of tlie prin- 

 ciple, in submarine constructions, to protect 

 wood, as in piles, from tlie action of worms ; 

 sheathing of copper defended by iron in 

 excess may be used, when the calcareous 

 matter deposited will gradually form a coat- 

 ing of the character and firmness of hard 

 Btcme. 



Logarithms, — We mentioned in our last 

 number that eleven new errors had been 

 <li~:covercd in the last edition of Callet's 



ibles (Tirage 1823), and expressed a 

 ;.oubt of their having as yet been made 

 public. We see that they have now been 

 published in Schumachoi's Astrononiisclie 

 Nachricten, and copied into tlie Bulletin 

 des Sciences. In the latter work, how- 

 ever, they are so incorrectly given, that we 

 consider the following enumeration of them 

 will be found extremely useful. 



fur read 



Sin 2° 10' 35" . . 8-5795294 . . 8-o79o094 

 Sin 2 39 23 .. 8-CG60184. .. 8-0600134, 



Tan 3 12 43 

 i'an 3 34 20 

 Sin 3 38 8 

 Tan 3 37 16 

 Sin 4, 43 39 

 Tan 4 51 14 

 Tan 4 53 55 

 Cot 13 31 30 

 TanW 14 50 

 Maijnetism.- 



.. 8-7491027 .. 8-7191007 



,. 8 •7953491 .. 8-7953791 



.. 8-8020567 .. 8-8021.567 



.. 8-8012780 .. 8-801-2980 



,. 8-9150100 .. 8-9100100 



.. 8-9280079.. 8-9290079 



.. 8-9330113.. 8-9330103 



,. 0-81881-22.. 0-0188122 



. 9 •9885608.. 9-9885808 

 •We mentioned in our last 



number what Professor Ilansteen had been 

 led to consider as the position of the two 

 northern magnetic poles of the earth ; from 

 the conclusion of his paper, inserted in the 

 lust number of the Philosophical Journal, 

 we give the position of the two southern 

 ones in the years 1773 and 1774, one to the 

 luth of New Holland, distant from the 

 pule of the earth 20° 33', longitude from 

 Greenwich 130° 15' E., with a motion to 

 the westward amounting to about 4' "09 per 

 annum ; the other to the south of Terra 

 del Fuego, LK;,tant from the terrestrial pole 

 1-2° 4.3', longitude from Greenwich 236° 

 43' E., with an annual motion of 16' "57 

 westwjird. Whence we see that the two 

 magnetic poles in the northern hemisphere 

 move eastward, while those in the southern 

 hemisphere move west«'ard. 



Gigantic Fossil JJones. — In the last num- 

 ber of the Boston Journal of PhilosopI:y an 

 account is given of the discovery, in the 

 low prairie grounds between Placquemire 

 and the Lakes, of some fossil remains, 

 which, from their gigantic size, render cre- 

 dible the extraordinary relations given by 

 Father Kircher and Bishop Pontojiedon of 

 the Kraken and Norway sea snake. If the 

 monster to M-hicli these bones belonged 



were of the Balxna species, its length 

 could not be less than two hundred and 

 fifty feet. But the information communi- 

 cated to the public on the subject is as yet 

 too imperfect for any very probable con- 

 jecture to be hazarded with regard to it, 

 and we look forward with much eagerness 

 to the future reports of the American natu- 

 ralists. 



Atmosjiherical Pressure — From a com- 

 parison of the various meteorological jour- 

 nals througJiout the country, it appears that 

 the mean lieight of the barometer in the 

 year 1825 was greater than the mean of the 

 last eleven years. 



Improved nwt/iod of blasting Rocks.— The 

 method of blasting invented by Jessop is 

 exclusively jiractised in the quarries of So- 

 leure, and admits of some applications, as 

 in the lifting of blocks out of their places 

 after being blasted, of great service — it con- 

 sists in simply covering the powder with 

 sand. The greater the diameter of the 

 hole, the coarser must be the sand. A va- 

 riation in the nature of the charge has beer» 

 introduced by M. Varnbegen, of Brazil ; 

 for example — the hole 3 5 inches in diame- 

 ter, and thirteen feet deep ; a mixture was 

 made of five pounds of powder, and twice 

 its volume of deal wood saw-dust, sli^-^tlf 

 moist, and sufficiently finar to pass a sieve 

 having holes two lines in diameter. Thi» 

 mixture was pressed lightly into the hole, 

 and filled it to a height of 7-5 feet; after 

 placing a match, the remaining 55 feet were 

 filled with sand. According to the report 

 of the workmen, the explosion produced as 

 complete and satisfactory an effect as would 

 have been produced by twelve pounds of 

 powder applied in the usual manner. — Hib. 

 Univ. 



Improved Microscopes. — Compound mi- 

 croscopes, both refracting and reflecting, 

 can be placed completely on the same 

 footing with telescopes, and reduced to the 

 same accurate discipline in their construc- 

 tion. Tliey are in fact nothing but tele- 

 scopes adapted to act with diverging rays 

 instead of parallel ones ; Dr. Goring sug- 

 gests in the Quarterly Joiunial of Science, 

 that the term engiscope would perliaps be 

 very applicable to them in their pei-fect 

 form, wliich appears to be an improvement 

 by Dr. Goring upon the reflecting ones 

 constructed by Professor Amici of Mo- 

 dena. 



Indian Gun-barrels. — The gun-barrels 

 made at Bombay in imitation of those of 

 Damascus, so much valued by the Orien- 

 tals for the beauty of their twist, are manu- 

 factured from iron hoops obtained from 

 European casks, mostly British. — Trans. 

 Soc. Arts. 



Suspension Bridge in Russia. — It is 

 stated iu the Annaies des Mines, that it 



