i 



1823.] Scientific Intdligence* 89? 



VII. Test of Platinum, 



Prof. Silllman recommends the hydriodlc acid, as the best test for 

 platmum in solution. When dropped into a weak solution, it almost 

 immediately produces a deep wine red, or reddish-brown colour, 

 which by standing grows very intense. It resembles the effect of 

 muriate of tin, but is more sensible. On remaining a day or two, films 

 of platinum were deposited. The hydriodic acid had been prepared, 

 by putting phosphorus to about an equal bulk of iodine, placed under 

 water in a glass tube, so that it remained mixed with acids of phospho- 

 rus, and perhaps phosphorus itself. No other metallic solution gave 

 similar results. — (Silliman's Journal, vi. 376.) 



^ VIII. Westbury Altitude and Azimuth Instrument. 



To most of our astronomical readers it is probably known, that on 

 the return of the Westbury circle to London during the last winter, it 

 was found in a state ** unfit for any nice astronomical purpose :'* it has, 

 however, under the superintendance of Mr. Troughton, undergone a 

 complete repair; to secure the telescope from flexure, its original object 

 glass of 2| inches aperture, and 4'3 inches focus, has been replaced by 

 one of the like diameter, but whose focal length is 38 inches only ; it 

 separates many of the close double stars, shows distinctly the double 

 ring and belts of Saturn, and was made by Mr. Tully. The artist who 

 has had the immediate management of the repairs is Mr. Simms, of 

 Bowman's-buildings, Aldersgate-street, and we are glad to know that 

 an instrument which has rendered such essential service to astronomical 

 science is again fit for immediate use. We quote the inscription it 

 now bears with pleasure. *' With this instrument, the work of Edward 

 Troughton, Mr. Pond substantiated the errors of the Greenwich mural 

 quadrant ; the observations were made at Westbury, and are recorded 

 in the Philosophical Transactions. The instrument, having suffered 

 from long exposure to the weather, was repaired and redivided for 

 Mr. South, by William Simms, under the direction, and to the satisfac- 

 tion, of its illustrious maker." — Aug. 10, 1823. 



IX. Correctness of Greentvick Observations, 



For some time past we have seen with regret the various attempts 

 which have been made by certain closet astronomers to withdraw the 

 confidence of the public from observations made at the Royal Obser- 

 vatory, and we have waited with much anxiety for the period, when 

 their accusations, and still more dangerous insinuations, should be 

 repelled. That time, we rejoice to say, is arrived ; a communication 

 has, we understand, been received from Mr. Bessel, acknowledging 

 that his Catalogue of Principal Stars requires a Correction for Instru- 

 mental Flexure; thereby admitting the superiority of the GreenwicI^,, 

 one. For this distinguished foreign astronomer we entertain the 

 highest respect; but, when his observations differed so seriously with 

 those made at our own great national establishment, we hesitated not 

 which to confide in ; and we are glad our confidence has not been mis- 

 placed. To such as have most distinguished themselves by their patriotic 

 . endeavours to depreciate the labours of their countrymen, we would 

 offer the following advice : — Use your pens less freely; your instru- 



