6 THE APPENDAGES, ANATOMY, AND RELATIONS OF TRILOBITES. 
time was devoted in the main to its solution by preparing these trilobites and learning their 
anatomical significance. 
The specimens of Triarthrus becki from Rome are pseudomorphs composed of iron 
pyrites, as has been said, and are buried in a gray-black carbonaceous shale. A little rub- 
bing of the specimens soon makes of them bronze images of the former trilobite and while 
under preparation they are therefore easily seen. However, as the average individual is 
under an inch in length and as all the limbs other than the antennae are double or biramous, 
one lying over the other, and the outer one fringed with a filamentous beard, the parts to 
be revealed by the preparator are so small and delicate that the final touch often obliterates 
them. These inherent difficulties in the material were finally overcome by endless trials on 
several thousand specimens, each one of which revealed something of the ventral anatomy. 
Finally some 500 specimens worthy of detailed preparation were left, and on about 50 of 
these Beecher's descriptions of Triarthrus and Cryptolithus were based. 
The black shale in which the specimens are buried is softer than the pseudomorphous 
trilobites, a condition that is of the greatest value in preparation. With chisel and mallet 
the trilobites are sought in the slabs of shale and then with sharp chisels of the dental type 
they are revealed in the rough. At first Beecher sought to clean them further by chemical 
methods, and together with his friends, the chemist Horace L. Wells, and the petrologist 
Louis V. Pirsson, several solutions were tried, but in all cases the fossils were so much 
decomposed as to make them useless in study. Therefore Beecher had to depend wholly on 
abrasives applied to the specimens with pieces of rubber. Much of this delicate work was 
done on a dental lathe, but in the final cleaning most of it was done with patient work by 
hand. Rubber has the great advantage of being tough and yet much softer than ekher speci- 
men or shale. As the shale is softer than the iron pyrites, the abrasives (carborundum, 
emery, or pumice) took away the matrix more quickly than the trilobite itself. When a 
part was fully developed, the rubbers were cut to smaller and smaller dimensions and the 
abrading reduced to minute areas. So the work went on and on, helped along from time to 
time by the dental chisels. Finally Beecher became so expert with these fossils that after 
one side was developed he would imbed the specimen in Canada balsam and fix it on a glass 
slide, thus enabling him to cut down from the opposite side. This was done especially with 
Cryptolithus because of the great scarcity of material preserving the limbs, and two of these 
revealed both sides of the individuals, though they were then hardly thicker than writing 
paper. 
Then came illustrations, which at first were camera-lucida drawings in pencil smoothed 
out with pen and ink. "In some quarters," however, it has been said, "his methods unknown, 
their results were not accepted; they were regarded as startling, as iconoclastic, and even 
unreliable." He therefore decided to rework his material and to illustrate his publications 
with enlarged photographs. The specimens were black, there was little relief between fossil 
and matrix, and the ammonium chloride process of coating them white and photographing 
under artificial light was unsuitable. Nevertheless, after many trials, he finally succeeded 
in making fine enlarged photographs of the trilobites immersed in liquid Canada balsam, with 
a contact cover of glass through which the picture was taken, the camera standing vertically 
over the horizontal specimen. Beecher had completed this work in 1903 and in the winter of 
1903-1904 was making the drawings, nearly all of which are here reproduced. On Sunday 
morning, February 14, 1904, as he was working at home on a large wash drawing of Cryp- 
tolithus, death came to him suddenly, leaving the trilobite problem but partially solved. 
