W. M. Fontaine— West Virginia Asphaltwm Deposit. 409 
sented if a certain allowance was made. If an unshielded 
collodion plate were presented to the image of the spectrum, 
there would be produced a stain very dense from G to H, fainter 
above H, and still fainter below G. But this stain would not 
represent the actinic force of the sun; it would merely be the 
index of the decomposability of a mixture of iodide and 
bromide of silver. I have for this reason adopted the idea of 
J. W. Draper, that force is equally distributed through the 
spectrum, and have tried to produce a photograph of equal 
intensity throughout. This has been accomplished, as I have 
before stated, by suitable diaphragms. But whether this view 
be correct or not, lines which are not far distant from one an- 
other are presented virtually without any interference by dia- 
acl and must therefore be correct both as to shading and 
mtensity. 
University, Washington Square, New York. 
<2 ya 
a. XLV.—Notes on the West Virginia Asphaltum Deposit ; 
We Wm. M. Fontaine, Professor of Nat. Hist. Univ. of 
est Virginia, 
In Ritchie County, West Virginia, occurs a remarkable de- 
ne of bituminous matter, for which the name “Grahamite 
oa proposed, ; 
t his substance, in its chemical properties, is strikingly like 
® mineral “ Albertite,” of New ick, while in its 
8e0lovical relations it differs considerably from it. Like 
