394 
POPULAR SCIENCE REVIEW. 
sufficiently under his control to use it for all purposes of qualitative and 
quantitative blowpipe analysis ; but he has been unable to obtain the red 
opaque copper bead on the eye of a platinum wire in the deoxidising flame. 
The bead thus produced shows the characteristics of glass, coloured by 
protoxide of copper. When removed out of the inner flame, the bead is 
perfectly colourless and transparent, and remains so after cooling ; but 
when again gently heated by holding it close to the flame, a beautiful 
ruby red diffuses itself through the glass without disturbing its trans- 
parency. This colour is not affected by cooling, but disappears by ex- 
posure to a stronger heat, and does not return on cooling. It can, how- 
ever, be reproduced by a low heat as in the first instance. The changes 
are best observed when the end of the platinum wire is made rather wide, 
and not too much borax used, so that the head becomes elongated. If a 
little copper is dissolved in the flux, the glass is rendered colourless in the 
deoxydising flame, and if now one end of the bead is brought near the 
flame, this half turns ruby red, whilst the other half is left too cold to take 
the colour ; but the first half when left for a moment in the exterior flame, 
becomes colourless by over-heating, and at the same time the other end is 
heated sufficiently to redden in its turn. The reader should consult the 
article itself for much that is interesting in regard to the subject it treats on. 
GEOLOGY AND PALAEONTOLOGY. 
Newly-discovered Bone Gave.-— In making certain excavations in the rock 
of Gibraltar, the engineers have come upon a very extensive cavern 
containing the bones of numerous extinct mammalia and of man. From 
what we have already heard, this grotto bids fair to throw more light upon 
the question of the age of pre-hist oric man than any hitherto examined . 
As yet we have had no minute description of the fossils discovered in this 
locality, but we have been informed that a very great number of specimens 
has been forwarded to this country by one of the Gibraltar authorities 
particularly interested in the geology of the excavation. 
Experimental Researches upon the Granites of Ireland is the subject of a 
paper lately presented to the Geological Society by the Rev. Samuel 
Haughton, F.R.S. The mineral constitution of the fifteen classes of 
granitic rocks was discussed in detail. Professor Haughton concludes from 
his investigations that nearly half of these granites are not composed 
altogether of the four minerals— quartz, ortho-classe, oligo-classe, and black 
mica— which are found in them in distinct crystals ; and that the remain- 
ing varieties, even if they be composed of these minerals, must have a 
paste composed of the same minerals, but with a slightly different compo- 
sition. The writer then treated of the composition of the syenites of 
Donegal, and instituted a comparison between the granites of that district 
and those of Scotland and Sweden, remarking that those of the. last-named 
country have the same stratified structure as the granites of Donegal. — 
Vide the Geologist for February. 
Band stone Hammer in a Diluvial Deposit . — In a letter to the editor of 
