8113

III. ELECTRICITY, TELEGRAPHY, ETC.--Optical Telegraphy.--
Cryptography.--Preservation of Telegrams.--The projector in
optical telegraphy.--Use of balloons. 4 figures. 8114

A New Style of Submarine Telegraph. 4 figures. 8115

A New Circuit Cutter. 2 figures. 8115

New Micro Telephonic Apparatus. 5 figures. 8116

Messrs. Kapp and Crompton's Measuring Instruments.
5 figures. 8116

IV. GEOLOGY, ETC.--Permeability of Sand Rock.--By F.H. NEWELL. 8103

The Grotto of Gargas, in the Pyrenees.--Paleontological
remains found therein. 2 engravings. 8103

Remarkable Wells and Caverns in Yucatan.--By ALICE D. LE
PLONGEON. 8105

V. NATURAL HISTORY.--The Cabbage Butterfly and the Peacock
Butterfly. 8105

VI. BOTANY AND HORTICULTURE.--The Bhotan Cypress (Cupressus
torulosa).--With engraving. 8106

The Pitcher Plant. 8106

What is a Plant? 8106

Camellias.--Culture of the same. 8106

Arisaema Fimbriatum.--Leaf, spathe, and floral details.--With
engraving. 8107

VII. MISCELLANEOUS.--Striking a Light with Bamboo. 8107

Experiments in Memory. 8107

* * * * *

PERMEABILITY OF SAND ROCK.

By FREDERICK H. NEWELL, M.E.

Among oil producers, there has been much discussion as to whether the
sand rock in which petroleum occurs is of necessity fissured or is
still in its original unbroken condition.

The earliest and most natural theory, which for years was indisputed,
and is still given by some textbooks, was, that oil wells reached a
cavity filled with petroleum.

Within the past few years, however, the opinion has been gaining
ground that the oil is stored in the sandrock itself in the minute
spaces between the small grains of sand, not entirely filled by
cementing material, and that crevices holding and conducting oil are
rare, all fissures as a rule being confined to the upper fresh-wat