Intelligence and Miscellaneous Articles. 315 



tacle of a definite portion of the tail being deflected from the axis, 

 or direction in which the general body of light continued to proceed. 

 Perhaps about one- sixth of the train might be thus drawn aside 

 from that which may be termed the natural direction, so as to form 

 therewith, at the point of separation, an angle which I should calcu- 

 late to be about three degress. . . . Five-sixths of the whole body of 

 light continued without interruption in the ordinary direction, the 

 remainder deviating from it in the manner here stated." 



VI. Observations made at the Observatory of Hamburg. By 

 C. Rumker, Esq. Communicated by Dr. Lee. 



The observations consist of: — 



1. Continuation of the Meridian Observations of the Moon from 

 1840, August 7, to 1841, February 12. 



2. Observations of the Eclipse of the Moon of 1844, May 31. 



3. Observations of Pallas and Ceres during their opposition. May 

 1844. 



VII. Scheme of Planetary Elements. By S. M. Drach, Esq. 



L. Intelligence and Miscellaneous Articles. 



PREPARATION OF THE PURPLE POWDER OF CASSIUS. 



MFIGUIER gives the following as a certain ^process for pre- 

 • paring the above-named compound : — dissolve 300 grains 

 of gold in five times their weight of aqua regia, prepared from four 

 parts of hydrochloric acid and one part of nitric acid ; evaporate the 

 solution almost to dryness ; this evaporation is requisite to get rid of 

 the acid. The chloride of gold being redissolved in water and fil- 

 tered, the solution is to be diluted till it measures 26 ounces ; frag- 

 ments of granulated tin are then to be put into it, which becomes 

 turbid and brown in a few minutes ; its tint gradually becomes 

 deeper, and at the end of a quarter of an hour it assumes a fine purple 

 colour, the precipitate is deposited, and it remains only to collect it 

 on a filter. 



It sometimes happens, and especially when large quantities are 

 operated on, that the precipitate does not separate, but remains in 

 the liquid, to which it gives a deep purple colour ; in this case it is 

 merely requisite to heat the liquid slightly and to add a little common 

 salt ; the product then immediately separates. 



When the liquid holding the purple powder in suspension is de- 

 canted to separate the excess of metallic tin, care must be taken that 

 no particles of tin, which remain at the bottom of the vessel in 

 the state of a black powder, are poured off with it ; it is proper to 

 allow the liquor to settle for some time and afterwards to decant it ; 

 this operation should be repeated three or four times. — Ann. de Ch. 

 et de Fhys., Juillet 1844. 



ON THE OXIDES AND SOME OTHER COMPOUNDS OF GOLD. BY 

 M. FIGUIER. 



In preceding Numbers we have stated the methods employed by M. 

 Figuier in preparing the protoxide of gold, and given his account of 

 its properties, we now proceed to the 



Auric Acid. — This is prepared by two processes : — 1st, by treating 



