28 ANNUAL REPORT. 
inexperience of the class is taken into consideration. One thing is quite 
markedly shown in this table and is corroborated by a large number of 
other tests, 7. e., the increase in tensile strength shown in the mortars made 
with the bank sand over those made with the other sands, especially in 1 
to 2 or I to 3 mortars. One of the important features of the table is its 
comparative value for illustrating the personal factor in cement testing. 
TABLE 4. 
Twenty-eight Day Tests of Cement Mortar Briquettes—1903. 
Standard Sand. Lake Sand. Bank Sand. 
ie 
Tester. Neat E 
ial jf Te | My) lei | a |) es | de | ee |) ee é 
CieBusheyenenr 799 | 747 | 466 | 285 | 581 | 868 | 216 | 584 | 427 | 291 |Atlas 
L. Hysenbach..... 800 | 767 | 400 | 231 | 585 | 822 | 182 | 602 | 418 | 867 | *“ 
Edw. Thomas ... | 770 |-524 | 359 | 210 | 474 | 221 | 222 |*393 |*802 |*265 | ‘ 
C. A. Melick......| 769 | 586 | 450 | 229 | 524 | 297 | 248 | 627 | 509 | 818 | “ 
K. R. Brashear. ..| 778 | 701 | 240 | 246 | 595 | 380 | 204 | 656 | 556 | 890 | ‘* 
Wi eebaLnyerrrine 813 | 700 | 442 | 206 | 560 | 312 | 203 | 682 | 492 | 342 | ** 
___ Averages... | 788 | 671 | 360 | 226 | 543 | 316 | 212 | 574 | 451 | 329 
©. W. Schubert...) 908 | 788 | 505 | 252 | 630 | 458 | 278 | 640 | 550 | 354 Giant. 
J. L. Murphy... .| 970 | 683 | 456 | 245 | 600 | 486 | 226 | 571 | 431 | 3818 | ‘*° 
C.L. Hill........./1015| 702 | 557 | 347 | 627 | 458 | 314 | 556 | 453 | 3864 | °° 
Jee Chubbasnns. 1231 | 868 | 600 | 381 | 733 | 476 | 866 | 687 | 649 | 472 | * 
Averages. . .|1031 | 746 | 529 | 306 | 647 | 457 | 296 | 613 | 521 | 377 | 
PHChubbe js: 681 | 490 | 439 300 514 | 406 | 316 | 570 | 504 418 Dyck 
J 
J. L. Murphy..... | 567 | 510 | 415 | 280 | 852 | 340 | 283 | 480 | 415 | 856 | “ 
Cals EL yes an | 480 | 460 | 484 | 802 | 426 | 362 | 283 | 520 | 444 | 842 | “* 
C. W. Schubert... | 620 | 485 | 3845 | 235 | 409 | 283 | 242 | 550 | 483 | 420 | °* 
Wi dh bariivye wee | 5381 | 412 | 312 | 174 | 887 | 837 | 242 | 567 | 442 | 3382 | “* 
C. A. Melick......| 442 | 463 | 374 | 250 | 329 | 264 | 233 | 606 | 510) 321 | ‘“* 
E.R. Brashear...| 618 | 467 | 390 | 235 | 393 | 355 | 282 | 580 | 496 | 266 | ‘ 
Edw. Thomas... .| 487 | 860 | 308 | 234 | 812 | 215 | 212 | 390 | 212 | 282 | “ 
L. Eysenbach.....| 532 | 8385 | 378 | 180 | 396 | 317 | 206 | 414) 483 | 3538 | “ 
C. L. Bushey..... | 640 | 425 | 370 | 189 | 354 | 800 | 249 | 418 | 425 | 3845 | © 
Averages. . .| 560 | 446 | 877 | 288 | 387 | 318 | 255 | 505 | 486 | 3389 | 
* Composed of a mixed sand. 
There may be several reasons for this increased strength of the bank 
sand mortar over the clean lake and quartz sands; but it is the writer's 
opinion that the principal reason is found in the smaller percentage of 
voids and the consequent surplus amount of cement which can go towards 
coating every particle in the aggregate. An examination of the table of 
characteristics of these sands shows that nearly one-half of the lake sand 
passes through a sieve of 2,500 meshes to the square inch. This accounts 
at once for the greater percentage of voids which must be thoroughly 
filled with cement in order to give greater strength to the mortar. This 
fine portion of the lake sand is composed of small, rounded and very 
smooth particles of quartz which naturally have no interlocking qualities, 
and must therefore depend entirely upon the adhesive powers of the ce- 
