889.] Botany. 
Sio, . SO3 Fe,03 ALO3 Lc 
91.12 5.30 .43 I- 
-Krohnkitc (Cu So, + Na, So, + 2 H,o) from Chili, is : 
c, according to Darapsky' with ^.- b: c=zi : 2.1 12: 
=6^° 8'. Its hardness is 2,5, and specific gravity, 
The Treatment of Exsiccati in the Herbarium.- 
Whether exsiccati should be kept as they are published, 
cut up and distributed in the Herbarium, is a question of sufl 
well indexed, are 
often labv: 
rinths tc 
) those wli 
to are unfamiliar 
with them. Tho: 
3e which ha 
ve a separate inde 
;x to each fasci- 
cuius are bad enc 
)Ugh, but, u 
mfortun; 
itely, man 
y of the largest 
and best sets ha\ 
^e no index 
: at all, 
and those 
whose indexes 
are published separately are 
: contini 
lallyoutgr 
owing them. If 
distributed in the herbariu 
m, the 
specimens 
; are always at 
hand, and a stud( 
-nt does nc 
»t need t 
2 indexes to see 
whether a given 
species is i 
n such c 
>r such a s 
;et, but can find 
all the specimens 
> from evei 
ry set to 
>gether in 
the herbarium, 
thus saving time and patience, and making comparison pf 
specimens more easy. Much of the synonomy becomes in 
time forgotten and obsolete, and many exsiccati are for this 
reason almost useless. But if distributed, the synonomy of 
«ach specimen can be kept up with the times by means of 
labels on the sheet on which it is mounted, and thus many 
specimens made useful which otherwise would be of but little 
value for reference. 
The common objection to cutting up and distributing exsic- 
cati is that it destroys their identity. But in most exsiccati 
the name, etc., is printed on the label of each specimen, and 
if not, these labels can easily be stamped. References to 
exsiccati are, as a rule, by number, but if distributed, the 
specimens can be found by name without the number, and 
when found the number is with them to show that they are 
the specimens referred to. Besides, if distributed, they can 
be found by many who have not noticed these references. 
' Neues Jahrb. f. Min., etc. 1889. I. p. 192. ,. , . , , 
^ This department is edited by Professor Charles E. Bessey, Lincoln, JNet). 
