SCIENTIFIC SUMMARY. 
127 
something which, appeared like a large cannon-ball. Knowing, however, that 
no artillery of so large a cahbre had ever been so far inland, he proceeded to 
examine it more closely, when he discovered that it was an aerolite. It was of 
a dark metallic colour, extremely hard, and about ten inches in diameter ; in 
fact, it resembled a ten-inch shot, and was about the same weight ; it was 
perfectly round, save on one side, which was slightly flattened, and its surface 
was extremely smooth, and very slightly perforated. He promises a further 
investigation of this interesting specimen. 
Rainless Districts. — In a letter to the Geological Magazine, Professor 
Ansted seems to imply that the term rainless district is only used in a rela- 
tive sense, and that there are no localities entirely immune from rain. Thus 
he says, it is convenient to call certain large areas “ rainless,” though rain 
occasionally falls on parts of them, and to include others among provinces of 
autumn or winter rains, which are as dry as the former. “ Certainly,” he 
writes, “ Canada and Ireland would not be incorrectly regarded as excluded 
from earthquake districts, though a shock now and then may be felt in 
either country.” 
MICEOSCOPIC SCIENCE. 
Tolies' Neiv Binocular Microscope. — It would appear that the celebrated 
American maker has produced an instrument whose power far exceeds those 
of any yet produced upon Mr. Wenham’s principle. It appears that apparatus 
by which the effect is produced is situated, not at the lower portion of the 
body, but is placed absolutely in the eye-piece, and hence can be easily 
adapted to any microscope, which it will only lengthen about three or four 
inches. On comparing it with a Smith and Beck’s binocular, with as low a 
power as •§ inch, there was observed a marked difierence as to definition 
both by reflected and direct vision. In the new instrument with the i-V inch 
the fine lines of Hyalodiscus suhtilis and Grammatophora subtilissima can be 
distinctly observed ; and even with the ^ inch the fine endings of the wedge- 
shaped markings on Podura may be easily perceived. “ The eye-piece, with 
its present arrangement, is a first-class erecting one, giving with the various 
powers up to the -rV fi^U and clear fields beautifully illuminated by the mirror 
alone, and without any special trouble with the higher powers, as is the case 
with Mr. Wenham’s arrangement.” Some facts as to the structure of certain 
of the diatoms have been brought out with wonderful distinctness ; there is 
a rotundity and solidity which gives a more complete idea of the structure of 
such forms as Aulacodiscus Petersii, and the Amphiprora, than can be had 
by any monocular vision. With the lower powers 3 inch to -f- or -y-V nothing 
can exceed the beauty and brilliancy of the objects when seen for the first 
time with the new apparatus.” The power of the eye-piece is variable, as 
with Wenham’s binocular. No alteration is required for polarization experi- 
ments ; but the prism is inserted in precisely the same place and manner as 
with the single eye-piece. In fact, the old arrangements of the microscope are 
left, the whole effect of binocular vision being produced in the eye-piece. 
The writer of the paper from which we have made the foregoing extracts, is 
not at liberty at present to explain the principle upon which Mr. Tolies has 
been enabled to divide the pencil so far from the objective, but doubtless 
