44-0 Dr. Stenhouse on the Resi?i of the Xanthoroea hastilis, 



conveying the combustion to a great distance through the 

 mine, while its continuity would be broken by such mixing, 

 and an explosion, when it occurred, be confined within nar- 

 rower limits. 



Secondly, no effective means exist for succouring the miners 

 after the occurrence of an explosion, although a large pro- 

 portion of the deaths is not occasioned by fire, or injuries 

 from the force of the explosion, but from suffocation by the 

 after-damp, or carbonic acid gas, which diffuses itself after- 

 wards through all parts of the mine. It is suggested that a 

 cast-iron pipe, from eight to twelve inches in diameter, be 

 permanently fixed in every shaft, with blowing apparatus, 

 above, by which air could be thrown down, and the shaft 

 itself immediately ventilated after the occurrence of an explo- 

 sion. It is also desirable that, by means of fixed or flexible 

 tubes, this auxiliary circulation should be further extended, 

 and carried as far as practicable into the workings. 



LXXIII. Observations on the Resin of the Xanthoroea has- 

 tilis, or Yellow Gum-resin of New Holland. By John 

 Stenhouse, Esq., Ph.D.* 



r I^HIS remarkable resin, which is known in commerce as the 

 "* yellow gum or acaroid resin of Botany Bay, exudes from 

 the Xanthoroea hastilis, a tree which grows abundantly in 

 New Holland, especially in the neighbourhood of Sidney. 

 This resin was first described in Governor Phillips's Voyage 

 to New South Wales in 1788. Mr. Phillips states that it 

 was employed by the natives and first settlers as a medicine 

 in cases of diarrhoea. The resin as it occurs in commerce 

 sometimes forms masses of considerable size, but as it is very 

 brittle, although tolerably hard, it usually arrives in the state 

 of a coarse powder. Its colour is a deep yellow, with a 

 slightly reddish shade, considerably resembling gamboge, 

 but darker and less pleasing. The colour of its powder is 

 greenish yellow. When chewed it does not dissolve or stick 

 to the teeth, but tastes slightly astringent and aromatic like 

 storax or benzoin. Its smell is very agreeable and balsamic. 

 When gently heated it melts, and when strongly heated it 

 burns with a strong smoky flame, and emits a fragrant odour 

 resembling balsam of Tolu. The resin contains a trace of an 

 essential oil, to which much of its agreeable smell is probably 

 owing. This oil passes into the receiver when the resin is 



* Communicated by the Chemical Society ; having been read November 

 17,1845. 



