COMPOSITION OF GAMBOGE. 
143 
With the ligneous fibre I have also included a trace of sandy- 
particles and other impurities. 
" 4. Ceylon Gamboge^ as I have seen it, is usually in small 
irregular fragments, but as originally collected is in ftattish 
round masses, as if moulded into shallow bowls, weighing 
about a pound or upwards; and it appears to be composed of 
aggregated irregular tears, with interspaces and cavities, which 
are lined with a dark powdery matter, or with a powder of 
an earthy appearance. Altogether it seems a very coarse 
article. But on attentive examination it will be found, that 
the tears, of which by far the greater portion of it is composed 
present the compact texture, smooth fracture, and glimmering 
lustre of fine Pipe Gamboge; that its powder has an intense 
gamboge-yellow tint; and that a smooth emulsion is very 
readily formed by it, with the wet finger. Dr. Duncan, in- 
deed, has stated that it has not the properties of true gamboge;* 
and I know he referred to its not being sufficiently emulsive 
to form a smooth mass with water for the use of the painter. 
But in this he is not quite correct. The specimen of concrete 
juice adhering to the bark, which was sent to him by Mr. 
Anderson Blair, is certainly not so emulsive as Siam Gam- 
boge. But the ordinary Cingalese article, also sent by the 
same gentleman, is much more perfectly so. And the speci- 
men sent by Mrs. Colonel Walker to Dr. Graham, as well as 
others subsequently sent to myself, comprising a splendid 
specimen of it adhering to the bark of the tree, seem to me 
to form with great ease an emulsion no wise inferior in 
smoothness, and very little, if at all in liveliness of tint, to 
that of the very best Pipe Gamboge of Siam. On this point 
I have taken the precaution of consulting an experienced 
professional colourist; and he reports that Mr. Anderson 
Blair's specimens present many fragments quite equal to the 
Pipe Gamboge as a pigment, but that it does not mix well 
with some other colours, such as Prussian blue, and shows a 
tendency to curdle with them — an objection, however, from 
* Edinburgh New Dispensatory, Ed. 1820, Art. Gamboge. 
