^04 Miscellaneous Intelligence. 



cceding' which it is affirmed preserves the position of the poles. 

 When the needle is magnetized, the same attention to its previous 

 state is to be given. — Bvll. de la Sec. Encourage^ 1827, p. 249. 



9. Alteration of Brass Wire in the Air. — M. Cagniard de la 

 Tour stated to the Academy of Sciences, that when long brass wires 

 were stretched for some days in the open air, especially in wet 

 weather, they became so brittle as to break with great facility v/hen 

 bent to a moderately acute angle. 



10. New Solar Phosphori, by M. Osann. — The solar phos- 

 phori, prepared in the following manner, are described as being far 

 more powerful in their effects than those previously known: — 



1. Oyster-shells are to be calcined ; the whitest and most porous 

 are to be selected, to be cleansed from all impurities, and then 

 packed into a crucible in the following manner. The bottom of 

 the crucible is to be covered with a thin layer of finely pulverized 

 sulphuret of antimony, then an oyster-shell is to be put in, this is 

 to be covered with more sulphuret, after which, a second shell is 

 to be packed in, and so on, until the crucible is full. The pow- 

 dered sulphuret should be spread uniformly by means of a fine 

 sieve, and each layer of it should be about half a line in thickness. 

 The crucible being closed, is then to be heated red hot for an hour. 

 "When cold, the upper and lower shells, if spotted, are to be rejected, 

 and the rest preserved. When exposed to sun hght, and then 

 taken into a dark place, it shines brightly at every part, with a 

 greenish-white light. A red heat applied for a long time causes 

 the light to be white. 



2. If the powder used be red sulphuret of arsenic (realgar), 

 instead of antimony, the light of the phosphorus produced, after 

 exposure to the sun's rays, is blue, like that of a sulphur flame. 

 The phosphorescence is not so universal as with the preceding, but 

 takes place only upon the white parts. Points occur here and 

 there producing light of a fine reddish purple colour. If heated 

 highly for a long time, the light produced by phosphorescence is 

 then white. 



3. Arseniate of baryta and gum, made into a paste, and heated 

 to redness for half an hour, produces a yellowish-gray substance, 

 which by phosphorescence yields a red light ; if heated more than 

 half an hour, the light is yellow ; if for a long time, the light is 

 white. 



Weaker phosphori are produced by using the following sub- 

 stances with the oyster- shells : mosaic gold, light bluish; cinna- 

 ber, light yellow ; white arsenic, light yellowish-blue ; blend and 

 sulphur, light bluish. All the phosphori may be preserved in jars 

 closed by bladder; even in the air they do not change rapidly : 

 three weeks' exposure did not diminish their power. When the 

 lime falls to powder, their effects are diminished. Those prepared 



