PHYSICAL TESTS OF THE PAPERS PRODUCED.

Samples of paper produced in the seven tests were submitted to the Leather and Paper Laboratory of the Bureau of Chemistry. The report of that bureau on its tests is given in Table III.

Table III.—Report of the Leather and Paper Laboratory of the Bureau of Chemistry on papers manufactured from hemp hurds.

Laboratory No.	RunNo.	Ash.	Weight of 500 sheets.		Thickness, 1/10000.	Strength (Mullen).			Strength factor (25 by 40, 500).	Folding endurance.
Laboratory No.	RunNo.	Ash.	25 by 38.	25 by 40.	Thickness, 1/10000.	Average.	Maximum.	Minimum.	Strength factor (25 by 40, 500).	Longitudinal.	Transverse.
		Per ct.	Pounds.	Pounds.
31570	144	13.9	48	50½	33	15.0	17.0	11.0	0.30	5	3
31571	143	14.5	49	51½	35	14.0	14.0	13.0	.28	4	4
31573	141	10.9	48	50½	38	19.0	20.0	19.0	.37	8	6
31572	142	9.5	49½	52	33	16.5	18.0	11.0	.33	10	8
31574	140	11.4	42	44	30	14.5	16.0	13.0	.33	7	6
31575	139	13.4	55	58	40	19.5	20.0	17.0	.34	8	5
31576	138	10.4	56	59	40	20.0	20.0	19.0	.34	23	15

There is no system of numerically recording the general appearance and "look through" of a paper, but it can be stated that only papers [ -25- ]Nos. 143 and 144 are satisfactory in these respects, the other samples being more or less thickly specked with shives. The general character and tests of these papers correspond very closely with No. 1 machine-finish printing paper, according to the specifications of the United States Government Printing Office, which call for a sheet not exceeding 0.0035 inch in thickness, strength not less than 12 points, free from unbleached or ground wood pulp, and ash not over 10 per cent. The strength factor of such papers is about 0.28. The ash should not be over 10 per cent for this grade of paper, but in spite of the larger amount used the physical tests are sufficiently high. It is to be noted that the physical tests of samples Nos. 138 to 142, inclusive, are higher than in Nos. 143 and 144, in which 23 per cent of soda poplar was used, which shows clearly that hemp-hurd stock imparts strength and folding endurance to a greater extent than does soda-poplar stock. From these preliminary tests it would be concluded, therefore, that hemp-hurd stock acts similarly to soda-poplar stock, but will produce a somewhat harsher and stronger sheet and one of higher folding endurance. Undoubtedly, there is more dirt in the samples than would be tolerated by the trade, but this was to be expected, since in this preliminary work the raw material was sieved by hand screens instead of by automatic machines which would sieve more thoroughly.