f the sun motor.

VI. HORTICULTURE.--Halesia Hispida, a Hardy Shrub.--With engraving.

Windflowers or Anemone.--With engraving.

VII. MEDICINE, HYGIENE. ETC.--What we Really Know about
Asiatic Cholera.--By J.C. PETERS, M.D.

Dr. Koch on the Cholera.

Malaria.--The natural production of malaria and the means of
making malarial countries healthier.--By C.T. CRUDELI, of Rome.

Story of Lieut. Greely's Recovery.--Treatment by Surgeon
Green.

VIII. MISCELLANEOUS.--Bayle's New Lamp Chimney.--With engraving.

Lieut. Greely before the British Association.

* * * * *

THE FRANKFORT AND OFFENBACH ELECTRIC RAILWAY.

The electric railway recently set in operation between Frankfort and
Offenbach furnishes an occasion for studying the question of such roads
anew and from a practical standpoint. For elevated railways Messrs.
Siemens and Halske a long time ago chose rails as current conductors. The
electric railway from Berlin to Lichterfelde and the one at Vienna are in
reality only elevated roads established upon the surface.

Although it is possible to insulate the rails in a satisfactory manner in
the case of an elevated road, the conditions of insulation are not very
favorable where the railway is to be constructed on a level with the
surface. In this case it becomes necessary to dispense with the simple and
cheap arrangement of rails as conductors, and to set up, instead, a number
of poles to support the electric conductors. It is from these latter that
certain devices of peculiar construction take up the current. The simplest
arrangement to be adopted under these circumstances would evidently be to
stretch a wire upon which a traveler would slide--this last named piece
being connected with the locomotive by means of a flexible cord. This
general idea, moreover, has been put in practice by several constructors.

In the Messrs. Siemens Bros.' electric railway that figured at Paris in
1881 the arrangement adopted for taking up the current consisted of two
split tubes from which were suspended two small contact carriages that
communicated with the electric car through the intermedium of flexible
cables. This is the mode of construction that Messrs. Siemens and Halske
have adopted in the railway from Frankfort to Offenbach. While the Paris
road was of an entirely temporary character, that of Frankfort has been
built according to