336 
ican formation below the mesozoic series. The asso- 
ciation with it of characteristic paleozoic forms of 
life, such as Zaphrentis, Phillipsia, Bellerophon, Con- 
ularia, Chonetes, and Productus, leaves no doubt as 
to its position ; and hence we must conclude that here, 
as well as in India, where Waagen first announced 
the occurrence of true carboniferous ammonitic 
forms, the distribution of this highly characteristic 
group of organisms was not so rigidly defined by the 
mesozoic line as geologists had been led to conclude. 
That pre-mesozoic Ammonites will be discovered else- 
where besides in India and Texas, there is no reason 
to doubt; indeed, no assumption could be more illo- 
gical than the contrary: and therefore the present 
discovery is in no way specially surprising, and only 
interesting rather than important. Special interest, 
however, attaches to this form; as through it, and the 
individuals or fragments that have been found in the 
Tejon (tertiary) rocks of California, we have estab- 
lished in this country the extreme range of the group 
which it represents. The name Ammonites Parkeri 
was proposed for the species. 
Philosophical society, Washington. 
Feb. 2.— Prof. C. V. Riley presented a review of 
recent progress in economic entomology; describing 
especially the development of insecticide methods. 
and apparatus, and closing his remarks with a plea 
for applied science. Dr. Swan M. Burnett dis- 
cussed the question, why the eyes of animals shine 
in the dark, giving a short digest of the subject, and 
describing experiments of his own. He concluded 
that the phenomenon was caused by reflection from 
the retina of the eye. It is seen best when the 
observer is on the line connecting the shining eye 
with a source of light, and ceases when his station 
departs from that line by a certain amount. The 
limiting angle (measured at the reflecting eye) is rel- 
atively great in the case of eyes which are hyper- 
metropic. Professor William Harkness pointed out 
that the limiting angle is likewise affected by the 
magnitude of the bright image on the retina, —— 
Mr. A. B. Johnson spoke on eccentricities of ocean- 
currents as illustrated by the voyages of lost buoys. 
At various times buoys have been torn from their 
moorings in the waters of the United States, and car- 
ried to sea; and eleven of these have been afterward 
found at distant points, and identified by means of 
letters cast in their constituent plates. One was 
found on the west coast of Ireland; asecond, at Pen- 
deen Cove, England; two others, just east of Tene- 
riffe; a fifth, near Turk’s Island; and a sixth and 
seventh, near Bermuda. The remainder were found 
in the open Atlantic, in the following positions: 
latitude 42° 22’, iongitude 26° 38’; latitude 29° 46’, 
longitude 717° 38’; latitude 30° 30’, longitude 28° 40’; 
latitude 24° 11’, longitude 32° 43’. Admiral Jenkins 
cited another instance of a U. 8. buoy stranding on 
the coast of Ireland. In the discussion which ensued, 
the opinion was expressed by Dr. William H. Dall 
and others, that the buoys found near Teneriffe had 
madea northward détour, and that those picked up 
SCIENCE. 
[Vou. TIT, No. 58. 
near Bermuda and Turk’s Island might have con- 
tinued on the same course, and afterwards turned 
west, completing the circuit of the Sargossa Sea; 
but it was thought more probable that the latter had 
followed the southward coastwise current inside the 
Gulf Stream. 
Feb. 16. — Prof. F. W. Clarke spoke on the periodic 
law of chemical elements, giving the history of the 
discovery of the law and of its verification by the 
subsequent discovery of elements indicated by it, and 
even specifically predicted. He exhibited an enlarged 
copy of Meyer’s atomic-volume curve drawn with 
the latest values for atomic weights and specific 
gravities, and presented a similar curve illustrating 
the connection between atomic weight and melting- 
point. Each curve presents a series of maxima and 
minima, the maxima of one corresponding to the 
minima of the other. The regularities of these 
curves indicate that the elements originated by some 
method of evolution, and that a feature of transmu- 
tation of one element into another is not impossible. 
Mr. Henry A. Hazen read a paper on the sun- 
glows, which has since been printed in the March 
number of the American journal of science. The 
first appearance of the phenomenon was at Mauritius, 
Aug. 28, 1883; and it was next seen at Maranham, 
Brazil, Aug. 30. It then appeared at irregular inter- 
vals on either side of the equator, until Nov. 26 and 
27, when it seemed to burst out over the whole world. 
After describing the nature of the phenomena, and 
Stating the principal theories which had been ad- 
vanced to account for them, he proceeded to advocate 
the vapor theory as follows: a. The glows are pre- 
cisely like the ordinary sunset phenomena, which are 
known to be caused by the presence of aqueous vapor; 
b. The abundance of the material so uniformly dis- 
tributed accords with the universality of the glows; 
c. The fact that faint stars and clusters could be 
easily seen indicates that nothing more opaque than 
water-vapor or frost-particles could be in suspension; 
d. Frost-particles might be repelled to a great height 
above the earth, and might be kept there by some 
form of electrical action; e. The fact of the spec- 
troscope giving no indication of an abundance of 
moisture does not militate against this theory, because 
it has been shown that ice-crystals or frost-particles 
do not affect the spectrum in arainband spectroscope. 
To the volcanic-ash theory he opposed the following 
objections: 1°. On this theory there must have been 
sufficient material ejected from Krakatoa, on Aug. 26 
and 27, to cover more than a hundred and thirty- 
five million square miles of the earth’s surface; 
2°. There must have been currents of early equal 
force, moving in opposite directions from the volcano; 
3°. The upper currents must have had a sufficient 
velocity to carry the ashes twelve thousand miles in 
a hundred and fifty hours (about eighty miles per 
hour) toward the west, while meteorology indicates 
no such velocities, and in general shows the upper 
current to be always toward the east; 4°. The ashes 
must have been mechanically distributed over the 
whole earth by air-currents; 5°. The phenomenon 
has been markedly intermittent; 6°. Volcanic ashes 
