436 
Dr. R. E. Root: ‘‘Iterated limits in general 
analysis. ’? 
Dr. Arnold Dresden: ‘‘Reduction of systems of 
linear differential equations of any order.’’ 
Dr. Louis Ingold: ‘‘ Displacements in a function 
space.’? 
Professor L. E. Dickson: ‘‘ History of the repre- 
sentation of numbers as the sum of squares.’’ 
Professor F. R. Moulton: ‘‘ Relations of families 
of periodic orbits in the restricted problem of 
three bodies.’’ 
Professor L. E. Dickson: ‘‘Note on Waring’s 
theorem. ’’ 
Professor L. E. Dickson: ‘‘ Uniqueness of divi- 
sion in Cayley’s algebras with eight units.’’ 
Professor J. B. Shaw: ‘‘On differential in- 
variants. ’’” 
Professor E. J. Wilezynski: ‘‘On some geo- 
metric questions connected with the problem of 
three bodies. ’’ 
Professor Peter Field: ‘‘On Coulomb’s laws of 
friction. ’’ 
Dr. E. G. Bill: ‘‘ Analytic curves in non-euclidean 
space.’’ 
Mr. H. F. Vandiver: ‘‘Theory of finite alge- 
bras. ’’ 
Dr. Arnold Dresden: ‘‘ Note on the second varia- 
tion; Jacobi’s equation and Jacobi’s theorem in 
the calculus of variations.’ 
Professor G. A. Miller: 
some related group theory.’’ 
Professor R. D. Carmichael: 
linear functional equations.’’ 
Professor R. D. Carmichael: ‘‘On the theory of 
the gamma function.’’ 
Mr. Vandiver’s paper was communicated to the 
society through Professor Dickson. In the absence 
of the authors, the papers of Mr. Vandiver, Dr. 
Bill, Professor Miller and Professor Carmichael 
were read by title. 
The next meeting of the Chicago Section will be 
held at the University of Chicago, on Friday and 
Saturday, April 5 and 6, 1912. 
H. HE. SLAvGHT, 
Secretary of the Section 
‘“Gauss’s lemma and 
“On a class of 
THE BOTANICAL SOCIETY OF WASHINGTON 
THE 78th regular meeting of the society was 
held at the Cosmos Club, Tuesday, February 6, 
1912, at 8:00 P.M. President W. A. Orton pre- 
sided. Thirty-seven members were present. Dr. 
H. W. Wollenweber and W. W. Ashe were elected 
to membership. 
SCIENCE 
[N.S. Vou. XXXV. No. 898 
The following papers were read: 
Conditions Favorable to Septoria lycopersici Speg.: 
J. B.S. Norvon. 
The author reported on a series of observations 
made on the development of Septoria under various 
conditions affecting growth. 
The Relation of Soil Acidity to Plant Societies: 
A. W. SAMPSON. 
Since the day of Unger and Thurmann there has 
been considerable difference of opinion as to the 
relationship between soil chemistry and cover. The 
fact, however, that different soils support different 
plants is a matter of common observation. The 
bearing of soil acidity upon this point has been 
investigated by the author—chiefly in connection 
with range revegetation studies conducted in the 
Wallowa Mountains of northeastern Oregon. 
The Leguminose are commonly extremely sensi- 
tive to acid soils while many ericaceous species 
are rather closely confined to acid soils. For 
example, Trifolium repens fails in soils requiring 
for neutralization the relatively small amount, 
locally, of 5,000 pounds of lime per acre foot, 
while no species of Vaccinium is known that can 
be grown successfully in neutral or alkaline soils. 
Again, some genera (e. g., Populus and Rosa) are 
apparently indifferent as regards soil preferences. 
The preeminent forage plant of the Wallowa 
Mountains, Festuca viridula, varies very widely in 
adaptability to acidity. The soils on which it 
grows luxuriantly vary in lime requirements from 
5,000 to 41,000 pounds per acre foot. The four 
species of Poa and the two species of Agropyron 
occurring locally reach their best development on 
calcareous and neutral soils. 
Notes of Travel in Central America: Professor A. 
S. HircHcock. 
Having visited the Canal Zone as members of 
the Smithsonian Biological Survey, Mr. Hitchcock 
and his son made a two months’ side trip to Cen- 
tral America. Collections were made in Costa 
Rica at Port Limon, San José and Puntarenas, in 
Nicaragua at San Juan del Sur, Corinto, Masaya 
and Jinotepe, in Honduras at Amapala, in Sal- 
vador at La Union, Acajutla, Santa Ana and San 
Salvador, in Guatemala at Guatemala City, Vol- 
cano Agua and Port Barrios. Mr. Hitchcock pre- 
sented notes on the various incidents connected 
with travel in the countries mentioned and re- 
viewed briefly the botanical results of the journey. 
W. W. STOCKBERGER, 
Corresponding Secretary 
