(Issued December 6, 1890.)
By request of the Committee of Revision and Publication of the
Pharmacopoeia of the United States of America, Prof. F.W. Clarke,
chief chemist of the United States Geological Survey, has furnished a
table of atomic weights, revised upon the basis of the most recent
data and his latest computations. The committee has resolved that this
table be printed and furnished for publication to the professional
press. The committee also requests that all calculations and
analytical data which are to be given in reports or contributions
intended for its use or cognizance be based upon the values in the
table. It would be highly desirable that this table be adopted and
uniformly followed by chemists in general, at least for practical
purposes, until it is superseded by a revised edition. It would only
be necessary for any author of a paper, etc., to state that his
analytical figures are based upon "Prof. Clarke's table of atomic
weights of December 6, 1890," or some subsequent issue.
This table represents the latest and most trustworthy results, reduced
to a uniform basis of comparison, with oxygen=16 as starting point of
the system. No decimal places representing large uncertainties are
used. When values vary, with equal probability on both sides, so far
as our present knowledge goes, as in the case of cadmium (111.8 and
112.2), the mean value is given in the table.
The names of elements occurring in pharmaceutical, medicinal,
chemicals, are printed in italics[1]:
[Transcriber's Note 1: ITALICS represented by surrounding with "_".]
Name. Symbol. Atomic Weight.
_Aluminum_. _Al_ 27.
_Antimony_. _Sb_ 120.
_Arsenic_. _As_ 75.
_Barium_. _Ba_ 137.
_Bismuth_. _Bi_ 208.9
_Boron_. _B_ 11.
_Bromine_. _Br_ 79.95
Cadmium. Cd 112.
Caesium. Cs 132.9
_Calcium_. _Ca_ 40.
_Carbon_. _C_ 12.
_Cerium_. _Ce_ 140.2
_Chlorine_. _Cl_ 35.45
_Chromium_. _Cr_ 52.1
Cobalt. Co 59.
Columbium.[1] Cb 94.
_Copper_. _Cu_ 63.4
Didymium.[2] Di 142.3
Erbium. Er 166.3
Fluorine. F 19.
Gallium. Ga 69.
Germanium. Ge 72.3
Glucinum.[3] Gl 9.
_Gold_. _Au_ 197.3
_Hydrogen_. _H_ 1.007
Indium. In 113.7
_Iodine_. _I_ 126.85
Iridium. Ir 193.1
_Iron_. _Fe_ 56.
Lanthanum. La 138.2
_Lead_. _Pb_ 206.95
_Lithium_. _Li_ 7.02
_Magnesium_. _Mg_ 24.3
_Manganese_. _Mn_ 55.
_Mercury_. _Hg_ 200.
_Molybdenum_. _Mo_ 96.
Nickel. Ni 58.7
_Nitrogen_. _N_ 14.03
Osmium. Os 191.7
_Oxygen_.[4] _O_ 16.
Palladium. Pd 106.6
_Phosphorus_. _P_ 31.
Platinum. Pt 195.
_Potassium_. _K_ 39.11
Rhodium. Rh 103.5
Rubidium. Rb 85.5
Ruthenium. Ru 101.6
Samarium. Sm 150.
Scandium. Sc 44.
Selenium. Se 79.
_Silicon_. _Si_ 28.4
_Silver_. _Ag_ 107.92
_Sodium_. _Na_ 23.05
Strontium. Sr 87.6
_Sulphur_. _S_ 32.06
Tantalum. Ta 182.6
Tellurium. Te 125.
Terbium. Tb 159.5
Thallium. Tl 204.18
Thorium. Th 232.6
Tin. Sn 119.
Titanium. Ti 48.
Tungsten. W 184.
Uranium. U 239.6
Vanadium. V 51.4
Yterbium. Yb 173.
Yttrium. Yt 89.1
_Zinc_. _Zn_ 65.3
Zirconium. Zr 90.6
--_Am. Jour. Pharm._
[Footnote 1: Has priority over niobium.]
[Footnote 2: Now split into neo-and praseo-didymium.]
[Footnote 3: Has priority over beryllium.]
[Footnote 4: Standard, or basis of the system.]
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