JANUARY 25, 1901.] 
and reflection. It was carried out by means of 
a special photometer, allowing the use of any 
desired angles of incidence and of reflection. 
Among the surfaces tested were plaster of 
Paris, several kinds of unglazed paper, com- 
pressed powders of several kinds, powders not 
compressed, but gently smoothed with a metal 
plate, and finally a surface made by allowing 
fine plaster dust to settle from suspension in the 
air on a suitable plate. These surfaces in the 
order named, showed decreasing polarization of 
the reflected light, and less approach to specu- 
lar reflection. The fine dust surface showed no 
polarization, and almost no tendency to regular 
reflection. The results with this surface, as 
shown by sets of curves, follow pretty closely 
the old Lambert’s, or cosine, law, 
Intensity = A cos7cosr. 
with some departure when both angles were 
very large. With all the other surfaces the de- 
parture was very great for angles greater than 
70°. Contrary to the results of Mr. Wright 
(Phil. Mag., Feb., 1900), these experiments were 
quite in accord with the demand of theory that 
the intensity of the reflected ray should be ex- 
pressed as a symmetric function of the angles 
of incidence and reflection. 
WILLIAM S. Day, 
Secretary. 
CHEMICAL SOCIETY OF WASHINGTON. 
THE regular meeting was held on December 
13, 1900. The first paper was read by Dr. 
Bigelow and was entitled, ‘The Composition of 
the Ash of Meat Extracts,’ by W. D. Bigelow 
and H. McK. Chace. The relation between 
solids and ash and between the several ash con- 
stituents were discussed in analyses of about 
40 commercial meat extracts and of juices pre- 
pared from fresh beef. 
The second paper, read by Dr. Cameron, was 
entitled, ‘ Formation of Sodium Carbonate or 
Black Alkali by Plants,’ by F. K. Cameron. 
The view popularly held, to which Hilgard, 
Goss and others have called attention, is found 
to be correct. It seems probable that the phe- 
nomenon is very widespread, but does not as- 
sume practical importance, except under special 
conditions in the arid regions. A discussion of 
SCIENCE. 
149 
the réle of mineral nutrients in soil solutions 
accompanied the consideration of the data ex- 
perimentally determined. 
The last paper, read by Dr. Cameron, was 
entitled, ‘Resistance by certain Plants to Black 
Alkali,’ by F. K. Cameron. It has been found 
that a few plant specimens exist which can 
grow in soils containing much sodium carbonate. 
Three such plants were examined. It was 
found that these plants had an organic acid or 
acids formed on their surface, sufficiently strong 
to decompose alkaline carbonates. It is be 
lieved that this acid, or acids, aid in lowering 
the concentration of the alkaline carbonates in 
the soil immediately about the plants, and thus 
protect the root crowns from the caustic action 
of the black alkali. 
WILLIAM H. KrueG, 
Secretary. 
PHILOSOPHICAL SOCIETY OF WASHINGTON. 
THE 527th meeting was held January 5th, the 
new President, Mr. Walcott, Director of the 
Geological Survey, in the chair. The evening 
was devoted to geodetic papers. 
Mr. Himbeck presented informally the ques- 
tion of an apparent error arising in transit ob- 
servations from the fact that at a locality where 
there is local attraction of the plumb line the 
geodetic meridian and the astronomical merid- 
ian differ sometimes as much as 30’. 
The first regular paper was read by Mr. Isaac 
Winston on ‘The Thirteenth General Confer- 
ence of the International Geodetic Associa- 
tion,’ held at Paris last fall, at which 17 
countries were represented, and to which he 
was a delegate. The principal papers pre- 
sented there dealt with recent work at gravity 
stations, the question of variation of latitude, 
the proposed revision of older triangulations in 
France and Peru, the nickel-steel alloy with 
small coefficient of expansion, and the recent 
and prospective measurements of terrestrial 
ares. [This paper is printed above. | 
Mr. Schott followed with an interesting his- 
torical account of such measurements, pointing 
out that the Clarke spheroid agreed better than 
Bessel’s with the American observations. Mr. 
Hayford described more fully the simple new 
nadir-zenith apparatus of Cornu, to which ref- 
