Zoology. 431 
would prove to be a true eye, however imperfect, there can be 
little doubt.” Talso stated that I left the subject to Dr. Leidy, 
believing that “he would be able to make out the complete 
anatomy of the eye of the Unio.” 
It was mentioned also in this paper that the females were more 
sensitive to light than the males. 
Subsequently i in the introduction to my vol. 6 “Observations on 
the Genus Unio,” &c., I mentioned the subject again, and stat 
that I had found that the Unio rubiginosus Lea, U. Cylindricus 
Say, and An. imbecillis Say, were all sensitive to light. 
n referring to my notes made since the above mentioned pub- 
lication, I find that duri ring the years Seas ’59, °60, I found the 
Lea, U. pyramidatus ars e obscurus Lea, U. pustulosus Lea, 
IV. MISCELLANEOUS SCIENTIFIC INTELLIGENCE, 
1. On the use of sodium in explosive powders.—Dr. H. Furck 
of Dresden has made an extended series of experiments on the 
use of sodium as an Satan of various eS and inflamma- 
ened glass rod. On filling a tube with gunpowder, placing a lit- 
tle of this oar on the top, sad throwing the P os e into water, 
sitts rae 8 
paycte st eras oN 20SbO s+3KOSO,+3N. 
The n xt point was the i seomuchipa ok of ae sodium. This Fleck 
has caseacanain doing by m of under which the so- 
dium is melted, and then nee finely vided by violently shaking 
the flask for five or ten minutes. A gran powder of a silve: lus-. 
ter is thus obtained, which when removed from the still liquid par- 
affine, does not tarnish, being erfectly protected by a thin coat- 
ing of this hydrocarbon which it retains, and which increases its 
we eight from 30 to 35 per part 6°6 grams of this sodium are sub- 
stituted for the 5 grams of or sodium in the above mixture B. 
To remove all traces of si m the other ingredients, they 
are well dried and then moistened with petroleum; the sodium is 
now added and the whole is well mixed together in ina Seotallie 
