i88 Foreign Literature and Science. 



48. Experiments on certain Oxalates. — M. Serullas 

 finds that when dry and pure oxalate of potash, either acidu- 

 lous or neutral, is finely powdered with an equal weight of 

 antimony and heated in a forge fire for eight or ten minutes 

 in a covered crucible, there is always procured a button which 

 is an alloy of potassium and antimony. 



When well dried oxalate of lead mixed with very small por- 

 tions of potassium, perfectly freed from naphtha, is put into 

 the bottom of a glass tube, air being carefully excluded, by 

 excess of the oxalate, a violent detonation suddenly takes 

 place, before the heat is sufficiently great to effect the de- 

 composition of the oxalate, when no potassium is present. 

 The tube is spotted with metallic lead, the potassium is oxi- 

 dized, and there is no carbon deposited. An examination of 

 the gas resulting from this instantaneous decomposition, may 

 elucidate the nature of the oxalates ; but hitherto the appa- 

 ratus employed has always been broken by the explosion. 

 Oxalate of copper treated in the same way also occasions 

 strong detonation, and metallic copper appears. 



Journ. de Pharm. Nov. 1 826. 



49. A method for facilitating the observation of distant 

 stations in Geodoetical operations. — Lieut Thomas Drum- 

 mond, of the royal engineers, having observed that quick- 

 lime when intensely heated, has the singular property of 

 giving out a most vivid light, availed himself of a ball of 

 that substance of the size of a pea, so placed in the focus of 

 a parabolic mirror as to admit of being intensely ignited by 

 the flames of several spirit lamps directed towards it by as 

 many streams of oxygen gas issuing from separate blow-pipes; 

 by which means a light of from seventy-five to ninety times 

 the intensity of a well trimmed Argand lamp was obtained. — 

 Quarterly Journal, Jan. 1827. 



50. Magnetic Influence in the Solar Rays. — Mr. Christie 

 has ascertained that a magnetic needle comes to rest more 

 quickly when vibrated and exposed to the rays of the sun, 

 than when vibrated in the shade, and this entirely independ- 

 ent of any mere effect of change of temperature. When 

 the needle was shaded, he could easily make the fiftieth 

 vibration ; when it was exposed, he could not distinguish 

 beyond the fortieth. — Idem. 



