FEBRUARY 22, 18S4.] 
instantly the whole body became spherical, rays were 
shot out, and the transformed monad was in no point, 
except that of size, to be distinguished from its Acti- 
nophrys-like relative. The whole development, from 
the time when the monad began its free life, occupied 
two hours and some seconds. 
Prof. H. C. Lewis called attention to a mass of 
cast-iron from the Emaus iron-works, near Allen- 
town. The iron contained crystals of graphite, which, 
again, held portions of cast-iron in their interior. The 
composition of cast-iron, which permits the formation 
of graphitic carbon, was considered, and compared 
with that of steel. Although the mass of iron must 
have been at one time in a molten state, it yet con- 
tained pieces of unaltered anthracite coal, which un- 
doubtedly remained unconsumed in consequence of 
the entire absence of the oxygen necessary for its com- 
bustion. The presence of such unconsumed pieces 
of coal in a mass of molten iron might be held as 
illustrating the way in which carbon may exist in 
meteorites, or chalcopyrite in trap rocks. 
Dr. Benjamin Sharp, referring to his recent com- 
munication on the visual organs of Solen ensis, stated 
that he had since determined the presence of similar 
organs in the mantles of the clam, the oyster, and the 
sand-clam. Their presence was made evident by the 
retraction of the mantles when shadows are passed 
over them. ‘The structure of the peculiar cells, sup- 
posed to be primitive eyes, was the same as that of 
the cells before described in the siphon of Solen, in- 
cluding the presence of the transparent portion at the 
end of each. 
Chicago academy of sciences. 
Jan. 14. — The committee, consisting of Dr. II. A. 
Johnson and B. W. Thomas, appointed to investigate 
the bowlder-clays underlying the city, made its -re- 
port upon a disk-shaped organism found both in the 
clays, and also in the filtrate from the water-supply, of 
Chicago. They were yellow, apparently flat or con- 
cavo-convex, and varied in size from ;; to 74, of an 
inch. Similar organisms have been found by several 
naturalists in the Devonian rocks of North and South 
America; and they were described by Dr. Dawson 
under the name of ‘Sporangites,’ and considered by 
him as macrospores of some acrogenous plant. Pro- 
fessor Orton of Ohio believes there are several spe- 
cies of varying sizes. We have, however, say the 
committee, none so large as discovered by Professor 
Orton. Our largest forms are not more than > of 
an inch in diameter, and our smallest about 34, of an 
inch. We have two, and possibly more, varieties. 
One has a well-marked ledge or zone around it, and 
extending, perhaps, an eighth of the way across it. 
Within this are the spines noted below. Others have 
no such markings, and do not, as a rule, have spines; 
and while some are a very light yellow, and almost 
transparent, others are of a dark reddish brown, and 
almost opaque. Whether these differences are sufti- 
cient to justify a separation of them into different 
Species seems to be at present doubtful. So far, no 
forms have been met with by either of us, having any 
thing like a stem or point of attachment. Nor have 
‘ 
SCIENCE. 
237 
we found any of: the spherical or oval sacs which were 
contained in the collections of Mr. Derby, in Brazil. 
There are found here, however, what we believe 
have not been found elsewhere; namely, on many of 
the disks, well-marked spines. These are, as a rule, 
clustered together, occupying a central portion, the 
diameter of which is three-fourths of the entire 
breadth of the disk, but in some instances the spines 
cover the entire surface. Along with these disks are, 
in quite large quantities, broken pieces of what seem 
to have been leaves, perhaps pinnate in form. Be- 
sides these, dark globular masses, which seem to be 
possibly spores or microspores, are frequently seen 
on the disks, and also scattered among them. These 
are — at least, in some cases —also contained within 
the substance of the disk. They are regular in form, 
and vary in size from j}$9 to z0c9 Of an inch in di- 
ameter. They are evidently organized; for in some 
cases there is seen a reticulum, or net-work, within 
the dark substance of the body. With these micro- 
spores, if such they are, are also masses of dark mat- 
ter that, at least in some cases, are made up either of 
these globular forms alone, or of these and other or- 
ganic material, such as the stems described by both 
Professor Dawson and Professor Orton. The clay 
beneath the city of Chicago and in the vicinity is full 
of bowlders of various sizes, from that of a walnut 
up to several cubic yards; and on many of these 
bowlders are well-defined ice-markings. Some of the 
smaller bowlders are shale which has never been 
ground down, and in these unchanged pieces we also 
frequently find large numbers of disks. These masses 
of shale, so far as we can ascertain, are identical with 
the shales of the upper Devonian formation. It will 
be seen that the disks are evidently not the product 
of their present location. They have been in some 
far-off age embedded in the shales; and subsequently 
these shales have been ground to clay, and, with other 
material constituting the bowlder-clays, have been re- 
deposited beneath the lake and the adjacent shores. 
They are now undergoing another dispersion ; for they 
are washed from their present position in the Chicago 
clays, and are mixed with the sands and alluvium, to 
be carried by the currents and winds to some new 
resting-place. Consequently our water-supply is now 
full of these products of probably some millions of 
years ago. They were perhaps water-cresses, and 
might have been of excellent flavor when fresh. 
They were fragant with gums or spices, as we know 
from their present composition. They are not now 
probably injurious to health, but they are especially 
valuable as a reminder, that in some widely different 
time, and amid very different surroundings, an abun- 
dant marine vegetation was being produced which 
has been preserved to our own day. 
Vassar brothers’ institute, Poughkeepsie, N.Y. 
Jan. 2. —C. B. Warring, Ph.D., exhibited the gyro- 
scope, and gave the explanation of its action the fol- 
lowing form. 
Dr. Warring, in giving his explanation of these 
phenomena, said it was important to clearly grasp 
these two principles: 1. A body set in motion will con 
