— 
106 Scientific Intelligence. 
9. On the Detection of Cotton in Linen; by G. C. Kinz, (Liebig’s 
Annalen, Feb., 1846; Chem. Gaz., April, 1847.)—This subject has 
frequently engaged the attention of commercial and scientific men; 
many experiments have been made in order to detect cotton thread in 
erto proved satisfactory. I was therefore much surprised when a 
stranger, a few weeks ago, showed me a sample of linen from the one- 
half of which all the cotton filaments had been eaten away. He ha 
obtained it in Hamburg, and asked me whether I could give him a pro- 
cess for effecting this purpose. Now since, as far as I am aware, 
nothing has been published on this subject, and it is of very general 
interest, I consider it a duty to communicate the results of my experi- 
ments. I had already observed, in experimenting with explosive cot- 
ton, flax, &c., that these two substances behave somewhat differently 
towards concentrated acids; and although it has long been known that 
strong sulphuric acid converts all vegetable fibre into gum, and when 
the action is continued for a longer period, into sugar, | found that cot- 
ton was metamorphosed much more rapidly by the sulphuric acid than 
naa “a 
ton emoved from linen when mixed with it; and this object 
may be effected by the following process :— 
The sample to be examined must be freed as perfectly as possible 
from all dressing by repeated washing with hot rain or river-water, 
boiling for some length of time, and subsequent rinsing in the same 
water; and | may expressly observe, that its entire removal is requisite 
for the experiment to succeed. When it has been well dried, the sam- 
ple is dipped for about half its length into common oil of vitriol, and 
kept there for about half a minute or to two minutes, according to the 
strength of the tissue. The immersed portion is seen to become trans- 
parent. It is now placed in water which dissolves out the gummy mass 
produced from the cotton; this solution may be expedited by a gentle 
potash or soda has the same effect,) and then to wash -it 
with water. After it has been freed from the greater portion of the 
moisture by gentle pressure between blotting-paper, it is dried. If it 
contained cotton, the cotton threads are foun be wanti 
portion which had been immersed in the acid; and by counting the 
the sample has been allowed to remain too long in sulphuric acid, 
the linen threads likewise become brittle, or even eaten away; if it 
