G6 
POPULAR SCIENCE REVIEW. 
perties of ordinary animal parchment, and so strong that it is 
only torn with great difficulty. The change is more remark- 
able inasmuch as no chemical alteration has taken place ; the 
acid simply produces a molecular change, and is entirely washed 
away from it as soon as the desired effect is produced. The 
applications of this novel material are very numerous ; its great 
strength (nearly double that of parchment), and its indestructi- 
bility by water or moisture, render it a valuable material for 
legal documents, such as policies of insurance, scrip certificates, 
deeds, agreements, &c. It is also used to replace vellum in 
bookbinding, and takes the place of ordinary paper in school- 
books, and other books exposed to constant wear. The manner 
in which it bears both oil and water colours renders it of value 
for artistic purposes ; the chemist now employs it largely for 
the new process of dialytic analysis, and ladies use it exten- 
sively to replace bladder in covering preserve pots, &c. 
But there is another class of rags — those from woollen 
materials — which cannot be thus employed for the purposes of 
the paper maker. Our readers are probably aware of the 
transformations which cast-off cloth garments undergo ; their 
change into “ mungo,” “ shoddy,” and “ devil's dust,” and their 
re-appearance as “ ladies' cloth ;” their subsequent degeneration 
into druggets, and final utilization for ornamenting our walls in 
the form of flock paper. These we pass over, and will trace 
the history of woollen rags after they have thus been tortured 
and wrought into every textile form which the ingenuity of 
manufacturers can devise. The fibre of the wool may have 
become physically completely broken up, and disorganized by 
repeated treatment, but its chemical value remains unaltered, 
and the large amount of nitrogen which it contains is too valu- 
able to be thrown away. Tons upon tons weight of this 
woollen refuse are sold for manure, and its excellent properties 
in tins respect are well shown by the perfection of the early 
brocoli which is supplied so plentifully to the London market 
from Cornwall. 
The class of goods called muslin- de-laine for a long time 
baffled the waste product utilitarian. The cotton fibre was 
valuable, and the woollen fibre was valuable, apart, but the diffi- 
culty lay in separating the two. Either of them, could be 
destroyed by chemical means ; thus, steeping the mixed fabric 
in acids converted the cotton-weft into sugar, when the wool 
was left available ; and, on the other hand, an immersion into 
an alkali dissolved out the woollen- warp and left the cotton. 
But the manufacturer was not satisfied with this ; he wanted 
both fibres; and Mr. F. 0. Ward has lately introduced, 
and illustrated in the chemical department of the Inter- 
national Exhibition, a most ingenious process by which this 
