SCIENTIFIC NOTES. 405 
eovery, in the sense of practical results, have yet to be measured ; but 
making this statement, it may be also at the same time fairly stated that 
the invention appears to be one of the most promising, if not the most 
promising of all those hitherto submitted to the quartz miner. 
Sodium was once retailed at twopence per grain, or at the rate of over 
£58 sterling per pound avoirdupois ; it was in those days a philosophical 
curiosity. From that to the present time it has gradually cheapened ; 
and, owing to its recent and extensive use in the production of alumi- 
nium, it has receded in price so as to be quoted at 10s. per pound. We 
see it even stated that in large quantities it may be had at 5s. per pound 
— a price which, although doubtless very low, may be quite within the 
limits of modern means of production. This, then, should enable us to 
form a basis for our calculations. We are to accept the use of sodium 
at so much per pound— say at its Melbourne market price, plus royalty 
or licence ; and we are to find our returns in gold heightened by as 
much more or less than the money value of the sodium thus used. 
The experiment on the large scale will demand a skilful, patient, not 
hasty, series of trials ; and the patentee and public, both equally 
interested in the success of the trial, must alike abide by the result. 
Mnilk IMw. 
West African Woods. — Notes on some woods sent to the Dublin 
Exhibition. 1. Black Mangrove (Rhizophora Mangle). This is the large 
twisted roots or branches of the common mangrove used for boat knees, 
timbers, &c. 2. Yellow Mangrove. This is the straight young trunks 
and branches of the same tree ; used for house building, poles, supports, 
rafters, &c. 3. Oroku. This is a fine, hard, dark-coloured, durable 
wood, much used for floors, ceilings, walls, doors, and cabinet work. 4. 
Iki. This is a new wood which has not yet been much employed here ; 
useful for cabinet work. 5. Brimstone Wood. A very serviceable wood, 
largely used here, principally in building, for floors, partitions, &c. 6. 
Native Oak : uses somewhat similar to Nos. 3 and 5. 7. Unnamed : 
used by the natives for making canoes, paddles, &c. 8. Similar to No. 
7. Paddles are made of it ; not much used. 9. Orupara. This is a fine 
hard wood, very similar to mahogany. It has never been tried yet, so 
we do not know its quality. I will send shortly the leaves of these 
trees for identification. — Edward J. L. Sjmmonds, Lagos, Feb., 1865. 
Products of the Vacoa (Pandanus utilis). — In the Mauritius, ex- 
tensive use is made of the leaves of this tree. With the leaves, bags for 
packing sugar are made, for which there is a large demand — considering 
