Scientific Intelligence. — Botany. 229 



tinura blowpipe of a single piece, formed of two hollow concen- 

 tric cylinders, communicating each by one of the extremities, the 

 one with a reservoir of hydrogen, the other with a reservoir of 

 oxygen ; while the two other extremities are pierced with con- 

 vergent openings, destined to effect the mixture of the gases. It 

 is well known that alumina is fusible with the oxygen and 

 hydrogen blowpipe ; but no one before M. Gaudin had endea- 

 voured to melt this earth into globules several millimetres in 

 size. Having submitted a portion of potash alum to the action 

 of his blowpipe, he obtained a perfectly round and limpid globule. 

 The platinum tube being perforated and melted at several places, 

 he obtained, after the cooling, instead of a limpid spheroid, an 

 opaque elongated globule, and covered internally with crystals 

 which may be referred to the rhombohedron or to the cube. 

 These ci-ystals scratch rocli-crystal, garnet, topaz, and spinel ; 

 with regard to hardness, therefore, they agree zvith the oriental 

 ruby. They appear to be composed solely of alumina, the pot- 

 ash volatilizing at the high temperature to which the alum is sub- 

 mitted. — Having obtained an apparatus stronger than the one 

 first used, he made an experiment with some ammoniacal alum 

 mixed with from four to five thousandths of chromate of potash; 

 the whole being previously calcined, he gave it the form of a 

 spherical cup, in order to obtain a maximum effect, by directing 

 the flame to the concave part. In a few moments the inner 

 surface of the cup was covered with globules of a beautiful 

 ruby-red colour, faintly translucent, and some of which exhibited 

 the form and cleavage of the ruby. M. Malaguti, who had oc- 

 casion to analyse these globules, found them to be composed of 

 ninety-seven parts alumina, one oxide of chrome, and two parts 

 of silica and lime ; which composition is analogous to that of the 

 ruby. 



BOTANY. 



16. Remarks an Dr Wight's paper regarding the Tree which 

 produces the Gamboge of Commerce, at p. 109 of this Number 

 were written in June las^ with a view to their insertion in the 

 then forthcoming Number of this Journal. I am glad that there 

 has not been room for them in an earlier Number than the pre- 

 sent, because I have since received additional, and what seems 



