JUNE 6, 1884.] 
Dr. F. A. Gooch began work in the laboratory 
on the 2d of April, and since that time has been 
occupied almost exclusively with analyses of spring- 
deposits and rocks collected in the Yellowstone 
national park. He has completed analyses of waters 
from the Giantess geyser, and the Excelsior spring 
(or geyser), both in the park, and of a basalt from 
the same region, and a rhyolite from Washoe, Nev. 
— Dr. Henry Erni also began work in April, and 
has been engaged in various mineral determinations 
of a qualitative character; notably, upon an alleged 
tin ore from Clay county, Ala., and phosphatic rocks 
and marls from Mississippi and Alabama. 
The following analyses have also been made at the 
laboratory at Washington: galenite from near Wash- 
ington; chlorite from Georgetown, D.C.; nephrite 
from Point Barrow, Alaska; margarite from Gaines- 
ville, Ga., and Iredell county, N.C.; copper ore from 
Lee’s ferry, Arizona; fulgurite from Mount Thielson 
in Oregon; and water from Bear River in Utah. The 
latter was collected by Mr. I. C. Russell, and proves 
to be an ordinary river-water; the greatest impurity 
being carbonate of lime, of which there are contained 
.1080 of a gram to the litre, the total solid contents 
being .1845 of a gram to the litre. The fulgurite was 
collected by Mr. E. E. Hayden, and is being made the 
subject of special study by Mr. J. S. Diller. Some 
of the results of his examination will be given in a 
future number. 
In the New-Haven laboratory, during March, 
Messrs. Barus and Hallock continued their high- 
RECENT PROCEEDINGS 
Engineers’ club, Philadelphia, 
May 17. — The secretary presented for Mr. Edward 
Parrish an illustrated account of the effect of sea- 
water on the iron of Brandywine shoal lighthouse. 
This lighthouse was built in 1849-50, near the mouth 
of the Delaware Bay, and stands in about six feet of 
water. It was the first screw-pile structure built in 
the United States, and had but few predecessors in the 
world. The house is supported on nine piles of ham- 
mered iron, surrounded by fifty-two piles of rolled 
iron, acting as an ice-fender. The whole is strength- 
ened by systems of braces and ties. The effect of the 
water on the iron, continually submerged, has been 
to produce longitudinal seams or grooves, with occa- 
sional holes on the surface, in some cases seriously 
reducing the strength. The most extensive corrosion 
is observed on the hammered iron. Round rods in 
the air are altered in section, approximating an irreg- 
ular polygon with longitudinal grooves. —— Prof. L. 
M. Haupt read a paper on rapid transit, giving val- 
uable data relative to the effects of velocity of move- 
ment on the ratio of increase of population, and 
contrasting the situation in New York and Philadel- 
phia. In comparing the topography of the two cities, 
SCIENCE. 
693 
temperature observations. Most of the work has 
been done with thermo-electric couples. The boil- 
ing-point of mercury has been redetermined with 
great accuracy. During April the boiling-point of 
zine was the subject of study. It seems probable, 
from the present outlook, that these high-tempera- 
ture researches will be very satisfactory in their 
results, and that they will render possible a wide 
range of investigations hitherto impracticable in the 
domain of physical geology. 
In the laboratory at Denver, Mr. Hillebrand has 
been busy with the chemical examination of rocks 
from the Silver-Cliff district. He has proved the 
existence, at this locality, of several minerals not 
hitherto known to occur in North America. The 
results of his examinations also point to the exist- 
ence, in one of these minerals, of silver in a very rare 
form, if, indeed, not in a combination hitherto un- 
known in the mineral kingdom. In March, eleven 
rock specimens were analyzed, and a number of in- 
teresting minerals from Ouray, Col. (some of them 
probably new to science), were examined. 
In the laboratory at San Francisco, Dr. Melville 
was busy, in March and April, with routine work 
connected with Mr. Becker’s investigations. 
Paleontology. —Prof. O. C. Marsh, in April, had 
two field-parties at work in Jurassic beds in Wyo- 
ming Territory, and one in the Jurassic in Colorado. 
Although the weather was very unfavorable during 
a great part of the time, interesting results were 
obtained. 
OF SCIENTIFIC SOCIETIES. 
a silhouette of Manhattan Island was laid on a map 
of Philadelphia (same scale), showing that the island, 
from the Battery to 150th Street (nine miles and a 
half), only extended from League Island to Erie 
Avenue. From this it was inferred, that, if there 
was need for elevated roads in New York, there was 
greater need for them in Philadelphia, ‘‘ as the neces- 
sity is proportional to the extent of surface of a city, 
and the distance of its residents from the business 
centres.’ The former commercial supremacy of 
Philadelphia was considered, with the reasons for 
the rapid decline in the ratio of increase of popula- 
tion, which has diminished from seventy-nine per 
cent in the decade 1840-50, to twenty-five per cent 
for 1870-80; while Camden’s population has increased 
from fifty-one per cent in 1850-60, to a hundred and 
eight per cent in 1870-80. In short, Philadelphia is 
overflowing because her time-limits of travel are too 
restricted. Assuming the time-limit at thirty min- 
utes each way, or one hour per day, at the usual 
velocities of travel, the limits of the ‘Pedestrian city’ 
were found to be a square with diagonals of 4 miles, 
and area 8 square miles; ‘ Horse-car or cable city,’ 
were found to be a square with diagonals of 6 miles, 
and area 18 square miles; ‘ Elevated railroad city,’ 
