ANNOUNCEMENT. 
HOW TO WORK WITH THE MICROSCOPE. 
By LIONEL S. BEALE, F.R.S. 
The FIFTH EDITION, Enlarged to 530 pages, with 100 Plates, price 21s. 
strongly bound, is Now Ready. 
HARRISON, Pall Mall. 
Now ready, in two volumes, Demy 8vo., £3 3s. 
A HISTORY OF BRITISH MARINE POLYZOA. 
By the Rev. Thomas Hincks, B.A., F.R.S. 
Containing an introductory sketch of the class in which the latest results of 
research are summarised, and a full and critical account of all the British forms. 
Illustrated by figures of the species and principal varieties drawn by the 
author and engraved on stone, forming upwards of eighty plates, and by 
numerous woodcuts. 
JOHN VAN VOORST, 1, Paternoster Row. 
NOW READY. 
in One Volume, Demy 4^om^« In Cloth, with r8 Chrome and 
AURORA, THEIR CHARACTERS & SPECTRA 
By J. RAND CAPRON, F.R.A.S., 
Part I.-THE AURORA AND ITS CHARACTERS. 
tj it SPECTRUM of the aurora. 
part n i Imagneto.electric experiments in connexion 
F ‘ WITH THE AURORA. 
by THE SAME AUTHOR, 
Demy 8vo., Cloth, Price £1 ios., 
photographed spectra, 
r PRo.noranhs of Metallic, Gaseous, and other Spefira printed by the 
Permanent Autotype Process, with Introduftion, Description of Plates, and 
Index. 
LONDON : 
E. and F. N. SPON, 46, Charing Cross. 
