and Vegetable Colouring -matters by the Spectrum Microscope. 1 49 



i * £ . .-a 





tf Sill 1*1 



I 5 J 5 HI 



jo £ jo a jo g 



O > 3 ^ O (£ 



4i — 5 5£ ... 6| 9 . . 10 — 11 — 



The following examples will show how simple or more complicated 

 spectra may thus readily be printed and compared. I have chosen 

 solutions of similar tint, in order to show that the spectra of those 

 of nearly the same colour may be very different, or, if analogous, may 

 differ in details easily expressed by the symbols. The colour of each 

 is given after the name. Nos. 1, 8, 9, 10, 11, 12, and 13 can be 

 kept for a long time sealed up in tubes ; and the rest are easily pre- 

 pared. I have in all cases chosen that strength of solution which 

 gives either the most characteristic spectra or those best suited for 

 comparison with other allied colours. 



1. Cudbear in alum p (Pink) 3 8 11 . - 



2. Colour of Elder-berries with! 



citric acid. (Bed Pink) J 



3. Brazil-wood, with bicarbonate! * 

 of ammonia. (Pink) J 4£ — 5f 



5£— 8--9... 11 



Logwood, with bicarbonate of "I * 



ammonia. (Pink) j 3§ — 6{ 



The next four are spectra of blood, produced by the successive ad- 

 dition of the various reagents, as in detecting fresh stains. 



5. Fresh Blood. (Pale Scarlet) 3* — 4f 4| — 5£ 7 . . 8 - - 9— 



6. Citric Acid then added. 



}i 



(Pale Brown) / If ... 2* 4 ... 8 ... 9 — 10 — 



7. Ammonia then added. 1 * * 



(Pale Brown) J 3f . . . 4| 4£ . . . 5f 7 . . 8 — 10— 



8. Deoxidized haematin, from blood- \ * * 



stain 2 years old. (Pink) / 4^ — 5 5* . . . 6| 9 . . 10 — 11 — 



With these may be compared the two spectra which more nearly re- 

 semble those produced by blood than any I have yet seen : — 



* * 



9. Cochineal in alum. (Pink) 3f — 4$ . . . 5£ ~ 6f . . . 7* 



* * 



10. Alkanet-root in alum. (Pink) 3£ — 4f 5$ . . . 5| 



The following spectra of compounds derived from chlorophyll are 

 as complicated as any I have met with : — 



