often the cause of trouble to farmers. 11364

Pear Duchesse D'Angouleme.--The history of the famous pear
tree, with hints as to its culture and general treatment. 11362


II. BIOLOGY.--Development of the Embryo.--A note of some
interesting biological researches.--By Prof. PREYER,
of Berlin. 11365

The "Hatchery" of the Sun Fish.--A curious incident in the
life history of the common sunfish.--1 illustration. 11363

III. CHEMISTRY.--On Allotropic Forms of Silver.--By M. CAREY
LEA.--A continuation of this paper, containing one of the
most important researches in the history of silver, with
statement of interesting results attained. 11361

On the Occurrence of Paraffine in Crude Petroleum.--A
valuable contribution to the history of paraffine, with
reference to petroleum and ozokerite. 11361

Turpentine and its Products.--By EDWARD DAVIES.--A resume
of the work done by chemists in the turpentine products.
--The different compounds produced therefrom. 11361

IV. ELECTRICITY.--Electric Lighting at the Paris Exhibition.
--The Oerlikon works.--A very exhaustive exhibition of
electric apparatus described and illustrated.--12
illustrations. 11356