466 SCIENCE. 
beginning April 15. Every alternate lecture will -be 
given in the open air, at different localities of geo- 
logical interest in the neighborhood of the city. 
These field-lectures will take place on Saturdays, the 
excursions occupying the greater part of the day. 
The final field-lecture (June 21) will treat of,coal and 
the methods of surface and underground mining, as 
illustrated in the neighborhood of Hazelton, Penn. 
Visits will be made to the mines of,Mr. Coxe, at 
Drifton, and to the Hollywood colliery, near Hazel- 
ton, where the end of a coal-basin has been com- 
pletely uncovered. 
—It is hoped that the next annual meeting of 
the National educational association of the United 
States, to be held in the capitol building, Madison, 
Wis., July 15-18, will be the largest educational meet- 
ing ever held in this country. 
— An extended course of instruction in mineralogy 
will be given by Prof. H. Carvill Lewis, at the Acad- 
emy of natural sciences, Philadelphia, during the 
coming autumn and winter. 
— The two remaining lectures of the course of free 
lectures under the auspices ot the New-York academy 
of sciences, are, April 21, Recent discoveries in the 
prehistoric mounds of Ohio, by Prof. F. W. Putnam 
of Cambridge, Mass.; and, May 19, The glacial 
epoch in North America, by Prof. H. Carvill Lewis 
of Philadelphia. 
— Dr. L. Waldo has just completed the erection of 
a normal clock at the Yale college observatory, to be 
used as a mean-time standard in the horological work 
of that institution. The movement and pendulum 
are parts of the gravity escapement clock built by 
Richard Bond (No. 367), and which had a phenomenal 
record under Mr. Hartnup at Liverpool, and later 
under Prof. W. A. Rogers of Cambridge. The case 
from Dr. Waldo’s designs is built of cast-iron, with 
planed back and front, to which are clamped the plate- 
glass doors. The entire case rests upon two brick 
piers, which rise to the height of the movement, and 
insure stability to the pendulum suspension. Ther- 
mometers, a barometer, and a cup of calcic chloride, 
are placed within the case, which can be exhausted 
to any barometric pressure desired by an air-pump 
attached to its side. The escapement, and arc of vi- 
bration,can be observed and adjusted with the greatest 
accuracy. ‘The clock is erected in the clock-room of 
the observatory, which was specially built to secure 
uniformity of temperature. 
— During the week from June 28 to July 5, inclu- 
sive, itis proposed to institute a summer school of 
geology at the Delaware Water-Gap, Monroe county, 
Penn. Those desiring to join this class should make 
application to Prof. H. Carvill Lewis, Academy of 
natural sciences, Philadelphia. 
—In the neighborhood of the Puerto de Toledo, 
Madrid, the manufacture of artificial whalebone has 
been started. It is made from the horns of black 
cattle and buffaloes. It is said that the factory is 
provided with all modern improvements, and that its 
products are already competing successfully with 
similar articles which are imported from abroad. 
y 
[Vou. IIL, No. 62, — 
— The Engineer of Feb. 1 gives a’very easy. practi- 
cal suggestion for preventing the boiler-explosions 
which occur so frequently in the early morning, while 
the boilers are being fired up, after standing with fire 
in all night, and the water on the simmer. It is sug- 
gested that a little air and cold water should be forced 
into the boiler before vigorous fires are made, so as 
to impart some air to the water, and lessen its super- 
heated condition. 
— The new Sydney paper, The Australian graphic, 
is illustrated by typographic etchings on glass plates 
made by the process of Mr. H. S. Crocker. The writ- 
ing or drawing is executed with a resist crayon, made 
of a waxy material; and it need scarcely be said that 
hydrofluoric acid is used as the etching-fluid. It has 
been noticed that the tendency to undercutting is re- 
markably small, so that no precautions are required 
but an occasional stopping-out of the finer parts. . 
The glass plates are cemented down on metal blocks 
for use in the printing-machine; but it is not stated 
how the clearing-out of large whites, and the turning 
of the blocks, are effected. It is satd that the inventor 
originally intended to print from electrotypes taken 
from the glass; but this is found unnecessary in prac- 
tice, as no inconvenience is caused by the use of the 
glass itself in the printing-press. 
—M. Poincaré has been investigating the physio- 
logical action of petroleum-vapors, and gives his re- 
sults in the Journal de pharmacie et de chemie, vii. 290. 
He found that an atmosphere charged with petroleum- 
vapors, such as is respired by workmen engaged in 
the petroleum industry, proved fatal to guinea-pigs 
after periods of exposure of from one to two years. 
Dogs and rabbits, under similar treatment, manifested 
languor, and loss of appetite. The work-people them- 
selves complain only of an irritation of the mem- 
brane of the nose, and headache. It is nevertheless 
evident, that precautions should be observed, to pre- 
vent, as much as possible, the respiration of these 
vapors by the human subject. 
— The fourth part of the transactions of the Ottawa 
field-naturalists’ club shows marks of unusual ac- 
tivity on the part of so small a society (one hundred 
and thirty members), printing reports of no less than 
six different branches. The scientific papers are very 
fitly concerned mostly with local natural history. 
— Sixty-nine species of butterflies are credited to 
Maine, and briefly described by Prof. C. H. Fernald 
in a paper of 106 pages, appended to the annual report 
of the State college of agriculture and the mechanic 
arts, at Orono, Me., for 1883. 
— The catalogue of stars prepared from observa- 
tions at the Glasgow observatory, extending over the 
years 1860 to 1881, has just been published by Pro- 
fessor Robert Grant, the Royal society having con- 
tributed largely toward the expense of printing from 
the government-grant fund. ‘ 
— Mr. W. Mathieu Williams, in his usual science 
notes for the Gentleman’s magazine, mentions an in- 
genious application of oxalic acid by saturating blot- 
ting-paper with it. The blotting-paper will then not — 
