Sai _ Improvement in Photography. 
‘ Metals; . os 
Carboriate of lead; ~~. 59.83. 46 266 
ene of zinc, . REPO Bt a ee 
3 oe of iron ¥ ' 5.20. ..3:606 
os as : sy i nine aha i sib 9.70:..... 52.502, 
io) Magnesia, . SAR 6 asta ia AE Fo. SORES 
100.433 © 
Note 4 to No. 2.—William M. Uhler tried spprodinalign the pro- 
cess of amalgamation with No. 2, suffering the mercury to re- 
main in contact with the pulverized ore for several days, and 
found that 1 Ib, avoir. took up 419 grs. troy, which gave 145 Ib. 
5 oz. 16 dwt. 16 grs. to the nett ton hare of 2000 Ibs. — 
+ ai be eas Sa Noire’ 
“avs 
Ane. XI Resdiitae>.sabe elalasusaiveeiuanal 
tography ; by F. A. P. wanes Prof. deriamarmsassictice 
in the Univ. of ogee 
: Messrs. Editors,—1 dolnniiationdy ‘aboet a ay since, ke 
nection with Dr. Wm. H. Harrington of this place, a series ¢ 
experiments in photography, according tothe methods ‘of Mr. — 
Fox Talbot and pac Our attention” “was directa 
Reig sw oe 
* oth ditiane A: employed to render the surface of silver mote 
Sensitive to the action of light than it had yet been made. To 
determine the correctness of this opinion we instituted a va. 
riety of experiments, which, as they proved for the most part 
unsuccessful, it is unnecessary to detail. The coating formed 
by the direct. action of chlorine gas upon polished silver, was: 
not found to possess the «desired. photogenic» properties. We 
were led, therefore, to seek «whether by the’ decomposition. of 
some compound of the metal, a sensitive chloride could not” not be 
ueed. Mr. Talbot had already done this in the’ prepar 
of hinphotgetic patie but as it was our desire’ to avail our- 
oe «Nae pit ep formed re sas slat of age 
