There were/are quite a number of physical and chemical tests made by 
prospectors and miners, to determine the metallic content of various 
ores, that are facilitated by the use of small glass tubes. Just one of 
dozens of such tests, this being a example of one used used by cinnabar 
prospectors, is described here:

Phillips, Josiah Samuel [M.E.]
    1873   The explorers', miners', and metallurgists' companion. Second 
Edition. Published by the author [Printed by Trü 
<http://openlibrary.org/publishers/Tru%CC%88bner>bner, __San Francisco].

p195 "All the compounds of mercury, when fused with carbonate of soda, 
at a moderate level, are decomposed and reduced to the metallic state, 
which, arising in fumes, are again speedily condensed, at a slight 
decrease of temperature; so that if cold gold is placed therein, the 
amalgam thus formed on its surface evinces the presence of mercury. This 
may be tested in a closed glass tube, held over a spirit lamp, or over a 
clean piece of red-hot iron; and either a small strip of gold may be 
held in the tube for amalgamation, or the cold tube may be rubbed with a 
stick of clean wood, an iron wire, or glass rod, when the bright 
mercury, by being thus scraped into ridges, may be seen on the glass. 
This may be varied to suit your tools, as in an iron spoon, in a 
tea-cup, etc. etc."




On 2/2/2013 12:19 PM, Sarah Sportman wrote:
> Hello,
>
> I'm trying to identify a few artifacts we recovered from back yard contexts in a 19th century mining town in the Adirondacks.  We found six fragments of thin, clear glass tubes. They are a little smaller in diameter than a modern drinking straw and round in cross-section.  All are broken and each fragment is less than 3 inches long.  The fragments came from the yards of three different domestic sites, including a tenement house, a double house, and the superintendent's house. The sites were occupied from the mid 1870s to the mid 1890s.  Any help in identifying them would be greatly appreciated!
>
> thanks,
> Sarah
>