152 Intelligence and Miscellaneous Articles. 



They act similarly with warm and cold water, alcohol, aether, potash, 

 ammonia, nitric acid, and chlorine ; heated in a retort the same effects 

 are produced, and also by sulphate of alumina, and electricity ; the 

 latter agent has been especially observed as to the effects which it 

 produces upon madder. The hot infusion gave crimson-coloured 

 flocculi at the positive pole instead of yellow ones, and as they were 

 formed the liquor became colourless. These flocculi were insoluble 

 both in boiling water and in alcohol ; they do not melt by heat, and 

 at the negative pole they give out hydrogen. 



Tincture of litmus subjected to the action of the battery in two 

 tubes, communicating v/ith each other, became red at the positive, 

 and of a deeper blue at the negative pole. The red liquor was acid, 

 and the blue one alkaline. By evaporation the red liquid left a sub- 

 stance of a deep red colour, susceptible of being reduced to powder. 

 It was rendered blue by the alkalies, and was soluble in aether. By 

 spontaneous evaporation small particles of a bright red colour were 

 formed, adhering to the vessel ; this substance was less soluble in al- 

 cohol. 



The blue liquid again subjected to the action of the battery, be- 

 came colourless at the negative pole, and gave red matter at the po- 

 sitive. The colourless liquor, evaporated and burnt, left potash or soda. 



The red liquid give scrimson precipitates with the persulphate of 

 iron and nitrate of silver, and a violet precipitate with the subacetate 

 of lead. Tincture of litmus even forms crimson precipitates with ba- 

 rytes, water, muriate of barytes, subacetate of lead, sulphate of zinc, 

 persulphate of iron, nitrate of silver, and sulphate of copper. — Journal 

 de Pharmacie, October 1828. 



NEW CLASSIFICATION OF THE COLOURS OF THE RAINBOW. 

 To the Editors of the Philosophical Magazitie and Anitals. 



Gentlemen, — As every improvement, however small, in scientific 

 classification, is of some importance, it is presumed that the follow- 

 ing will be thought not unworthy of a place in your miscellany. 



I have often seen the rainbow, when very bright, repeated three 

 or four times, every repetition being gradually fainter; each set of 

 colours being half the width of the preceding (like the repeated 

 notes of the musical octave on a divided string or line); and suc- 

 ceeding according to the following classification,' which 1 consider 

 as more scientific than the common enumeration. 

 Red. 



n..o^^^ a;„;a„a • * f Reddish, called scarlet. 

 Urange, divided into < v^ i, • , ,,1 



1 Yellowish, called orange. 



Yellow. 



Green, divided into { gf "i^h"^''^' ''^"^^ ^°"'°''^' 



Blue. 



■p,,,.^}^ a:.;a^a • » ("Bluish, called indigo. 

 Purple, divided >nto | j^^^^^^ ^^j,^^ ^.^,^^^ 



Red. 



Orange, &c. Here 



