1876.] Microscopy. 307 
century, some of whom, if we are not mistaken, have got more than one 
of these new “ discoveries ” of ours marked on their maps! In short, 
we may say with the Irish school-master, when he found one of his own 
similes in Homer, “ Curse thim ancients, they ’ve stolen all our best 
` ! ” 
INUNDATION OF THE SAHARA. — The idea of converting the Western 
Sahara into an inland sea is discountenanced by Mr. E. G. Ravenstein, 
who thinks that the plan is premature. He claims that the natural out- 
lets of the Sahara are Tripoli, Algiers, Morocco on the north, the Atlan- 
tic seaboard on the west, and the Senegal and Niger on the south. “It 
is by these roads the necessities of the inhabitants of the Sahara are 
supplied, and their surplus produce is exported, and they will suffice for 
a long time to come.” 
Mar or Prenistoric Ruins 1N Cororapo. — A Preliminary Map 
of Southwestern Colorado and Parts of the Adjacent Territories, show- 
ing the Location of Ancient Ruins, issued by the United States Geolog- 
ical and Geographical Survey of the Territories, F. V. Hayden in charge, 
will be found of much use by archeologists and travelers, as it gives the 
localities of the ancient rock ruins and cliff-houses discovered by the sur- 
vey. 
MICROSCOPY.! 
San Francisco MicroscoricaL Society.— This working society 
now numbers about forty active members, and its annual receptions and 
semi-monthly meetings are well sustained. During the past year it has 
commenced the formation, by purchase and donation of books and sub- 
scriptions to magazines, of a suitable library, and has added to its supply 
of apparatus a Nachet microscope whose one-eighth objective, which has 
ho collar adjustment, with Nachet's oblique condenser, resolved promptly 
and easily into beads No. 19 of Méller’s test-plate. Among the nota- 
ble additions to the cabinet of slides are a series of slides of the wall 
tocks of the gold-bearing veins of California; a series of sections of 
the woods of California ; a slide of the curious diatom, Schizonema 
Grevillii, remarkable for its great external resemblance to some forms of 
alge, the frustules of which were contained in a regular tubular frond, 
m which they were living when found, and up and down the canal of 
Which they were seen to move; a slide of crystals of salt obtained by 
slow evaporation from the tear of a child; and a fragment of photo- 
8raphic paper mounted in balsam to exhibit the minute specks which are 
$0 annoying to the photographer, and which appeared as white spots con- 
taining a dark nucleus of an arborescent crystalline formation, black 
Oxide of manganese being believed to be the cause of the spots, and 
hydrochloric acid being suggested as a possible means of removing them. 
+e Work of the society seems to be mainly directed to the legitimate 
natural history applications of the microscope, though not without some 
! This department is conducted by Dr. R. H. Warp, Troy, N. Y. 
