46 RESIN OF NORWAY SPRUCE FIR. 



185O. equal in intensity to that of the other sort. Almost the only 

 difference that could be detected in these two samples (excepting 

 the absence of indigo in one) was, that the residuum of No. 1, 

 when coloured with an acid, was of a finer red than that of 

 'No. 2 similarly treated. This doubtless arose, from the indigo 

 in the latter partially obscuring the red colour. 



Various Accompanying these samples, which were from one of the 

 qualities of m0 st respectable litmus manufacturers at Amsterdam, our cor- 

 lus * respondent sent the price current of another maker, which I 

 inclose for thy inspection. It offers no fewer than twenty- 

 three different qualities of litmus, the cheapest of which is but 

 a ninth part of the value of the most expensive. We were 

 however informed (as we might indeed have easily supposed) 

 that several of the lower qualities of this manufacturer were 

 far from genuine. 



I remain, very respectfully thine, 



DANIEL HANBURY. 



[The price current referred to was that of Jan Dekker, of 

 Wormerveer, in Holland.] 



ON THE RESIN OF THE NORWAY SPRUCE FIR. 



(Abies excelsa.) 



IN the Materia Medica of the London Pharmacopoeia two 

 forms of the resin of the Norway Spruce Fir (Abies excelsa) 

 are enumerated : one, Abielis resina, called Common Thus or 

 Frankincense ; the other, Fix abietina, or Burgundy pitch. The 

 latter is stated to be the resin in a prepared state (Resina 

 prcp.parata) ; the preparation essentially consisting in the removal 

 of the impurities by straining. 



Abietis The first of these substances, viz., Abietis resina, is rare in 

 English commerce, and it was not until during a recent visit to 

 Switzerland that I had an opportunity of obtaining an authentic 

 specimen. In many parts of that country this species of Abies 

 is very abundant, forming extensive and beautiful tracts of 

 forest. The resin exudes spontaneously from fissures in the 

 bark of the tree, and especially from those places where 

 branches have been broken oft 1 . When it first issues, it is 



