C O N T E N T S, 



JANUARY 1798. 



I. Experiinents maHe with a View to arccrtnm the Caufe of B.iikling;, 

 wliith have metallic Cont'udors belonging to ihcm, being linick. by Light- 

 ning. By Lieutenant-Colonel Haldane — — p. 433 



GcDcral remarts. D.'fcription of the apparatus. Experiments. Conclurion. 



II. New Conftniflicn of the Air Pump. By James Sadler, Efq. Chemid to 

 the Admiralty — — — — — p. 411 



Two coiiftriiclions of air pumps, in wliich the vacuum is rendered more pcrfeft by the interpofition 

 uf a fluid. 



IIF. Obfervations on Phofphorus. By Citizen Brugnatelli, Profeffbrof 

 Chemirtry, Sec. at Pavia — — — p. 44+ 



Solution of phofphorus in ojcj'gene g;n«i becomes luminous by the addition either of the oxygenated 

 muriatic acid gas or nitrous jjas. Phofpliorus diflblved in hydrogene gas — Appearances of phof- 

 phorus in oxygenated munV.tic acid gas — in carbonic acid gas — and atmofpberic air. Sohition in 

 oil of turpentine, and alcohol ; effcdSs of water on the latter folution — and of other fluids. Phof- 

 phorated ether. Recapitulation. 



IV. On the Advantage of inverting the Slider in many Operations on the 

 common Sliding Rule. By the Rev. W. Pcaiibn, of Lincoln P- 450 



Methods of working arithmetical qutftions on Gunter's rule with the inverted Aider. 



V. AbRradt of a Memoir entitled " Enquiries concerning the Nature of Pruflian 

 Blue." By Mr. Prouft — — — — p, 453 



Iron Is net oxidable at the intermediate terms between the extreme proportions of oxygene. It affords 

 two fulphates only ; the green crvftallizable, and the red not cryftallizable ; and there it no inter- 

 mediate fait. Properties of thefe. The green fulphate affords a white prufliate ; which rapidly 

 abforbs oxygene and becomes blue. The red fulphate affords the moft lively blue prufliate. The 

 yellow oxide of iron is as completely faturated with oxygene as the red. Pruflian blue is diloxy- 

 genated, and converted into the white prufliate, by keeping In a clofe veffcl with water and plates 

 of iron or tin. Other faiSs concerning the definite oxidation of metals. Ufeful obfervations on 

 Ink and the black dye. 



VL An Account of fome Experiments to determine the Force of fired Gun- 

 powder. By Benjamin Count of Rumford, F.R.S. M.R.LA. p. 459 



Gunpowder fired in a clofe veffel. Attempts to meafure its elaftic force. Detail of the appa- 

 ratus and experiments. An heavy weight was applied to the mouth of a metallic barrel, in order 

 that the explolion might tend to raife it. When the forte was InfufRcient to raiie the weight, it 

 did not continue to exert the fame aftion after the explofion as at the inftant of that event. Sin- 

 gular hard black refidue, of a pungent alkaline talle and hepatic fmell — concluded to have been in 

 the flaftlc ftate during the explofion. A barrel i inch bore, and 2| inches external diameter, 

 burft by 28 grains of gunpowder. Experiments and dcduflions from which It is inferred that a 

 force of 54750 atmofphcrcs was exerted in producing this cffcft. Oilier experiments. Table of 

 rcfulti. 



VIL Ob- 



