BULLETIN 39, UNITED STATES NATIONAL MUSEUM. 



[6] 



over several in succession lies in tlie less liability to fracture the si^ec- 

 imen so that it shall break in trimming. Having secured the spall, 

 hold it in the left hand as indicated in figure 5 and with the small 

 trimming hammer gradually work it down to the desired size and shape. 



Favorable dimensions for study series are about three by four inches by 

 not over one inch in thickness. If for exhibition purposes in museums, a 

 half inch more in each dimension adds to the appearance. In trimming 

 a specimen always work from the edge, striking sharp, quick blows 

 obliquely downward, as shown in figure 5, so that the chip separates 

 from the lower edge. I*5"ever strike directly across the edge, as, if the 

 specimen is at all thin, it is almost sure to break. Save, when trim- 

 ming, chips suitable for thin sections and chemical work and wrap with 

 the specimen itself. 



Always wrap a trimmed specimen (see figs. 6 and 7) carefully and pack 

 in such a way that abrasion of the surface through rubbing against other 





FIELD LABEL. 





Note book 



Date: 





Page 











H 



1 



Locality : 



a 



(72 



P 



» 



^ 



B 





> 









H 





^ 



3 





CO 



Z 





h 



^ 





H 



O 

 11 





1 



> 



w 





ri 







g 



02 



Remarks : 





Collector : 



Pig. 8.— Museum field label. 



specimens is impossible. Almost any kind of paper will answer. Write 

 the label in pencil, fold it, and wrap with the specimen. A sample of the 

 field label used by the I^Tational Museum is here reproduced (fig. 8). It is 

 well to first fold the wrapping paper once over the label to prevent its 

 being torn by being pressed too closely against the rough surface of 

 the rock. In packing, remember to pack closely and tightly so that 

 no movement can take place between the specimens themselves such 

 as shaU cause one to rub over the face of the next adjoining and 

 scar it. For purposes of study the fresh fracture is always desirable, 

 and, moreover, abrasive marks from the hammer or from rubbing, due to 

 poor packing, are unsightly and suggestive of carelessness. Always 

 label as fully as possible. 



Trust nothing to memory. Eemember that the exact site of a dike, 

 boss, or ledge of rock is a matter of primary importance since it may 



