MICROSCOPY OF PAPER. 97 
stumps, and leather-cuttings have been used experimen- 
tally for this purpose. Cotton and linen rags still fur- 
nish the best grade of paper. The manufacture of 
Manila paper is an important industry. Straw and 
wood-pulp, however, furnish by far the largest yield of 
coarse paper and cardboard. The relative importance of 
the different materials is indicated by the following table 
from the United States Census: 
PAPER-STOCK MANUFACTURED IN THE U. S. IN 1g00. 
Wood, cords.... 6.1... . eee eee eee 1,986,310 
Wood-fibre, tons. ..............20.. 644,006 
Straw; tonsisas scsehcauasiawuarcat tears 367,305 
Old paper, tons. .............. 00 eee 356,193 
RAS, TONS elo 5. tarase oss cect abatacacteanteic 234,514 
Manila, (ons. 0.2 ssuigaces oe sears 99,301 
3. The Microscopic Examination of Paper.—Before 
examining a sample of paper under the microscope, it 
should be torn into small bits and boiled in a one-percent 
solution of caustic soda. The wet pulp produced is 
washed on a fine sieve and broken up by shaking in water. 
The identification of paper fibres is by no means an 
easy task, and requires careful study and comparison 
with known substances. The student will be much 
aided by an admirable monograph prepared by Professor 
W. R. Whitney and Mr. A. G. Woodman, and pub- 
lished in the Technology Quarterly for September, 1902. 
The authors suggest the following points to be noted in 
the systematic study of each specimen: size of cells, 
shape, length, width as compared to length, shape of 
the ends, presence of knots or joints, whether the major- 
