WITH THE MICROSCOPE. 22/ 



With these may be compared the two spectra which more nearly 

 resemble those produced by blood than any I have yet seen. 



# * 



9. Cochineal in alum. (Pink) 3f 4i . . . 5g - - - 6 . . . y 1 



# # 



10. Alkanet root in alum. (Pink) 3^ 4^ 5? 5* 



The following spectra of compounds derived from chlorophyll, 

 are as complicated as any I have met with. 



11. Normal chlorophyll 1 , 



in alcohol. \ . * nT . f? _, 



(Deep Green}} 8 ' +- ' /5 ~ 



12. Ditto, as decom- ~] 



posed by acids, or ^ ^ , # # 



as found in some f> i2& 2^ 3^ 4} . . S\ - 5f 6-2- - - -7? 3|. - - 9! 



leaves. 



r /7^ G*;r t v/) J 





13. Ditto, as decom- ~] 

 posed by caustic 

 potash, and then 



by hydrochloric 1- I f Ij l| i| 2 45 - - - 5} . . . 9 - - 10 

 acid. 



(Red- Green, Neu- 

 tral Tint) 



In many cases the position of the centre of the absorption bands 

 is very characteristic of the different substances, and we may easily 

 express their differences by writing the division, group, sub-group, 

 and position of the bands, in the following manner : 



Purple pansy i,A,aq ami (4). 

 Brazil wood i,C ; aq, (5^). 

 Logwood i,C,aq, (4!). 



These signify that the colour of the purple pansy is soluble in 

 water and not precipitated by alcohol that sulphite of soda removes 

 the absorption band when added to the ammoniacal solution that 

 there is no absorption band in the neutral solution, but that on 

 adding ammonia a single absorption band is developed, whose centre 

 is at 4. In the case of Brazil wood and logwood, they signify that 

 the colour is also soluble in water and not precipitated by alcohol 

 that sulphite of soda has no action on either an acid or alkaline solu- 

 tion that in each there is a single absorption band in the neutral 

 aqueous solution, situated in different positions in the two colours, as 

 shown by fig. 321, B and C. 



I trust that this brief description will show that in practical 

 working a great deal may be easily expressed by very simple symbols. 

 We may soon decide to which group and sub-group any colour 

 belongs ; and, if we had a table of various known colours, arranged 



Q 2 



