388 Scientific Intelligence. 
little larger than the number 19°, which Kopp found so common 
with other classes of substances. 
. Lhat certain series of derivatives from the benzole series of 
hydrocarbons present boiling-point differences correspondin 
the elementary: difference of C,H,, considerably smaller than 
the number 19° of Kopp. 
4. That the formule of Schréder, Léwig, and Gerhardt, for 
the calculation of boiling-points, so far as these may be supposed 
to relate to the hydrocarbons, are incorrect and purely artificial. 
5. That the custom of taking boiling-points with the bulb of 
the thermometer in the vapor is more liable to lead to an erro- 
neous determination, at least in certain cases, than if the bulb be 
placed in the liquid, 
SCIENTIFIC INTELLIGENCE. 
Iron regions of Arizona ; by W. P. Buaxe (from a letter to J. D. ; 
om 
Dana, dated San Francisco, Cal., Aug. 31, 1865).—Your note in the 
Williams fork of the Colorado, observed by me in 1863. The ore is 
at a high angle. The whole forms a belt of peculiar appearance, 
which may be traced by the eye for miles across the country in a direc- 
ti 
ion a few degrees south of west, so pass over the Colorado, and into 
the limits of California. It is interstratified with chloritic and. tale f 
Slates, gneis anite, and the series has yielded both copper ores and 
Pe : 8} 
ferruginous formation extends over a considerable area north and south, 
and it may possibly be connected with the Mexican series, and 
silurian. The antiquity of the Aztec and the Aquarius ranges and the 
psa ee region about them, as compared with the Sierra Nevada 
i‘ : 
> OCKY mountains, was commented On by me in vol. iii, p. 4 
the Pacific R.R. Reports. At Williams fork a heavy white sand- . 
a conglomerate, of ancient appearance, overlie the granitic and meta-— 
' bl f the above iron-bearing roeks 
he first example 
