4 
On the Assay of Minerals by means of the Blowpipe. 439 
thus, Posidonius, Strabo, and Ptolemy, had drawn their in- 
formation from a people of still greater antiquity. He supposes 
‘them to have been the Hindoos, But it appears more probable 
to me that it was the Tartars and Chinese. The latter were ac- 
quainted long before any other nation, with printing, the mari- 
ners’ compass, gunpowder, the use of silk, and astronomy. 
~ The knowledge of the mariners’ compass announces that ¢hey 
were great navigators, and consequently they must haya had 
‘an extensive knowledge of geography. Their astronomical ac- 
quirements gave them the means of ascertaining longitudes and 
latitudes. The desire for travelling is now general, and learned 
travellers daily extend our geographical knowledge. Morier has 
given us some geographical details respecting Persia, Armenia, 
and Asia minor. Kimmel has published his Journey to Mount 
Caucasus. Mawe has made us better acquainted with the Bra- 
zils, and given us some interesting’ détails on the mineralogy of 
those countries, their diamond and gold mines, &c. 
[To be continued. } 
XCII. On the Assay of Minerals by means of the Blowpipe. 
By M. Haussman, Inspector General of Mines at Cassel*. 
Circumstances necessary to be observed in the preparation for 
the experiment : volume of the fragment to be assayed. 
Ir ought to be proportioned to the size of the flame to which 
it isexposed. If the aperture of the blowpipe be only the dia- 
meter of a pin, the volume of the fragment ought not to be 
larger than a pepper corn. In order to support the fragment, 
we may use: 1, Pincers of platina, or’ with platina points at 
least. 2. A small glass tube or eylinder, the end of which is 
to be softened in order to fix the fragment to it. 3. A small bit 
of cyanite, according to Saussure’s method. 4. Charcoal of 
good quality, particularly poplar and elm, flattened on one side, 
and with a small hole in it in which to place the fragment. We 
may cover this piece of charcoal with another piece ; and in this 
case a passage must be made for the flame, which ought to fall 
on the fragment contained in the hole. 5. We may compose 
a stud for support with charcoal dust pounded in mucilage of gum 
tragacanth. We must form of this paste parallelopipedons, 
and dry them slowly. 6. We may use a small spoon of gold or 
silver, but above all of platina, the end of which is fixed in a 
pipe or in a wooden handle, to preserve the fingers from being 
scorched, 
* Journal des Mines, Jan, 1811, vol. xxix, p. 61. 
: Ee4 As 
