Intelligence and Miscellaneous Articles. 309 



inclined to think I had over-estimated its dimensions. Probably a 

 fifteenth part of the solai- diameter would be nearer the truth. The 

 obscuration was however so large as to attract the notice of the most 

 unobservant. People in Prince's Street, I understand, were gazing 

 at it as they lounged along. Having no pretension myself to astro- 

 nomical acquirements, I can claim only to be considered as a simple 

 eye-witness to a fact, and shall be glad if chance has led me to cor- 

 roborate the observations of Sir J. W. Lubbock or others. The 

 latter gentleman, in his Note on Shooting Stars, also mentions having 

 recently seen other solar spots with the naked eye, which disappeared 

 altogether in a day or two. This I had read before receiving 

 his obliging communication. The natural inference from similar 

 repeated observations I imagine miust be, that the great forces in 

 operation on the solar surface are gradually increasing and extending 

 their energies ; so that we may possibly have, in process of time, 

 half of the sun's body obscured, as Abulferagius relates occurred in 

 the seventeenth year of the emperor Heraclius during the space of 

 nine months ! 'The solution of this mighty solar problem is yet to 

 be achieved ; and perhaps it would be a step to our knowledge of 

 the physical constitution of the sun, if by calculating the perturba- 

 tions of some comet, as suggested by Sir J. W. Lubbock, its origin 

 could be traced back to the solar mass, from which it had been pro- 

 jected by the tremendous forces there in obvious operation, 

 I am, Gentlemen, 



Your very obedient Servant, 

 Edinburgh, March 11, 1848. W. Pringle. 



ON A NEW METHOD OF DISTINGUISHING THE PROTOXIDE OF 

 IRON FROM THE I'EROXIDE BY THE BLOWPIPE. BY E. J. 

 CHAPMAN, ESQ. 



The presence of iron in any compound may be detected, it is well 

 known, and with great certainty, by the blowpipe; but no method 

 has hitherto been given by which the protoxide of iron can be 

 distinguished from the peroxide by means of that instrument. After 

 several trials to accomplish this, I discovered the following method, 

 wliich is both decisive and simple, requiring moreover for its per- 

 formance but the ordinary reagents of the blowpipe- case. 



A very minute quantity of oxide of copper is to be dissolved in a 

 bead of borax on tlie platinum wire until tlie glass be faintly coloured ; 

 and the substance under examination being added to it, the whole 

 is to be subjected, but for an instant only, to a reducing flame ; 

 when, if protoxide of iron were originally present in tiic assay- 

 matter, tiie CuO will be reduced to Cu'^ O, forming small red sjjots 

 or streaks, which become visible as the glass cools. The FeO is 

 converted into Fe*^ O^ at the expense of the oxygen of the copper. 



In the above experiment, if the glass were exposed for too long a 

 tiuK!, the (jxidc of cojjpcr might become reduced, even if the sub- 

 stuucc under examination contained only the peroxide of iron, as 



