GEOLOGY. 369 
Nore on Preservine Insecrs IN CoLLECTIONS.— I have devised 
a method for preserving insects without the trouble of camphor. 
No Psocus, nor Cheyletus eruditus, nor other pest dares enter a 
box after I have treated it. Having a clean-papered box I wash 
it with common carbolic acid (disinfecting solution) with two-thirds 
water. It dries without any stain, and I find, after many months’ 
trial, a perfect result. Sheets of card thus medicated give me all 
the small, soft Hemiptera, etc., with antenne, etc., not eaten by 
Psocus, as was formerly the case.— T. A. MARSHALL, in Entomol- 
ogist’s Monthly Magazine. 
GEOLOGY. 
Derr Sea Exprorations (Report Brit. Assoc. in Atheneum for 
Sept. 27).—The largest audience of the week was gathered to- 
gether on Tuesday morning (the final sitting), to hear Comman- 
der J. E. Davis discourse “On the recent Achievements of the 
Challenger Deep-sea Expedition.” Capt. Davis confined himself 
to the proceedings of the Challenger Expedition north of the 
equator, which formed a natural section of the voyage. The 
operations with which he chiefly dealt were the deep-sea soundings 
viewed in their relations to physical geography rather than to zo- 
ology, which, as is well known, occupies a large portion of the at- 
tention of the scientific staff of the Expedition. He described 
and exhibited to the meeting the various mechanical contrivances 
adopted to sound the greatest depths with accuracy, ascertain the 
temperatures, and bring up mineral and zoological specimens from 
the bottom. In the course of the voyage outward from the Thames 
to Gibraltar, and thence to Madeira and the Canaries, the first in- 
teresting set of soundings were taken off the entrance to the Straits 
of Gibraltar. The soundings over a large area in this section are 
as follows: just beyond the meridian of Cape St. Vincent, due 
West of the straits, 2,500, 2,125, and 2,250 fathoms; and, again, 
between Madeira and the Canaries 2,350, 2,400, 2,200, and 1,975 
athoms; but westward and northward, outside this area, the 
depths diminish to 1,525, 1,400, 1,550, and 1,650 fathoms. These 
results seem to indicate the existence of another deep basin out- 
side the Mediterranean, circumscribed by a ridge similar to the 
two deep basins within that sea. Great depths were found close 
Up to the islands of the Madeira and Canaries group, but a much 
AMER. NATURALIST, VOL. VIII. 
