56 Proceedings of the American Philosophical Society. 
The laws which govern the other grades of this defect, Dr. Hays re- 
marked, remain to be determined. 
There are certain persons who can accurately recognize yellow and — 
blue, and some who can recognize red, who cannot distinguish green; 
but whether or not there are individuals who can recognize the three 
primitive colors accurately, and are yet unable to distinguish the second- 
ary colors, must be left, Dr. Hays remarked, to further observation to de- 
termine. 
It also remains to be ascertained, whether any person, having an im- 
perfect perception of yellow, can ‘recognize blue; or with an imperfect 
perception of yellow and blue, or of the latter alone, can distinguish red. 
Sept. 18.—A letter from Dr. John Locke, of Cincinnati, stated the re- 
sults of two series of observations, each made with three horizontal nee- 
dles, and concludes from the mean of them, that the relative horizontal 
~ intensities at Louisville and Cincinnati, are as 1 to 0.9727. ~The dates of 
the observations were March 7th, 10th, 11th, and 14th, 1840, at about 
noon of each day. The correction for temperature, in ouek of the three 
needles used, was obtained by experiments which are fully described, and 
which gave the following coefficients —for needle No. 1, 0.000125; for 
No. 2, 0.000145 ; No. 3, 0.000058. 
The magnetic dip at Cincinnati, as detiralned by two series of obser- 
vations, each with two needles, in March, 1840, was 70° 25'.5, and by 
one series, in April, 70° 28’.8, and the dip at Louisville, by three series, at 
nearly the same date, in March, 69° 54'.9. 
The relative total intensities ‘dios deduced for a period correspandlal 
to March 10th, 1840, are,—Cincinnati, 1.000 ; Louisville, 1.003. 
Oct. 2.—The Committee, consisting of Dr. Horner and Dr. Hays, ap- _ 
pointed on the 3d of January last, to report to the Society a description 
of a donation of Mastodon Bones, made to the Society by a subscription 
of members, gave in their report, which was directed to be printed in the 
Transactions of the Society. 
The Committee, consisting of Dr. Hays, Mr. Peale, and Dr. Dunglison, 
to whom was referred a paper entitled ‘‘ Note of the Remains of the Mas- 
todon, and some other extinct animals, collected together in St. Louis, 
Missouri; by W. E. Horner, M. D., Profenicr of Anatomy, University of 
Pennsylvania,” reneriimliabead: that an abstract of the same should be in- 
serted in the Bulletin of the Society’s Proceedings; and on motion, the 
report was accepted, and the committee discharged. 
The collection referred to, was made by Mr. Albert Koch—a Germat 
resident in St. Louis, for the last five years—and has been obtained prin- 
cipally from two localities, Rock Creek, twenty miles south of St. Louis, 
and Gasconade County, two hundred suilea above the mouth of the Mis 
souri river. It consists of two hundred or more teeth of the mastodov 
and of the American elephant, a dozen or more lower jaws of the 
’ 
