[ 79 | 
Correspondence. 
To the Editor of the “ Scientific Enquirer.” 
DEAR SIR,— 
I am glad to learn that you have met with such help as 
will allow you to continue the publication of the SCIENTIFIC 
ENQUIRER. 
Could you induce one of your specialists to write a paper 
on the “Connection between Angular Aperture, and Mumerical 
Aperture,” for either the /ournal of Microscopy or Enquirer, 
I am a subscriber to both. 
A practical paper, clearly written for the average amateur, 
explaining the mathematical and other signs used would be of 
great value. 
Yours faithfully, 
By Re) BB. 
[We shall be glad to receive such a paper.—Ep. | 
Reviews. 
PHOTOGRAPHY SimpLirIED: A Practical Treatise for the use 
of Amateurs or Professionals. Third edition. Cr. 8vo, pp. xil.—160. 
(London : Mawson and Swan, 33, Soho Square. 1887.) 
To the amateur photographer this little book will prove of much service, 
containing as it does hints on the selection of apparatus and on general prac- 
tice. It treats each department in a very thorough manner, whilst the 
instruction given will be found to be plain and practical. At the end of the 
book will be found a complete set of bottle-labels for all the chemicals 
required in the laboratory. The price, 6d. or gd., will insure for this book a 
large sale. —— 
THE SELBOURNE MacazinE: For Lovers and Students of 
Living Nature. Issued by the Society for the Protection of Birds, Plants, and 
Places. (London: William Rice, 86, Fleet Street.) 
The first number of this magazine opens very fittingly with a paper on 
Gilbert White, of Selbourne. Other papers are on the Teaching of Elemen- 
tary Botany in Schools; Local Museums and the Observation of Living 
Nature ; An Open Aviary ; Notes of the Month; Wild and Tame Doves ; 
etc. On the cover of the magazine is a copy of rules to be submitted to the 
members of the society at their next meeting. 
SCIENTIFIC News for general readers. Nos. 1 and 2 of this 
new weekly have been received. Our friends will remember that last year it 
appeared as a monthly. We do not look upon the SciENTIFIC NEWs by any 
means as a rival, but hail it as a friendly ally, and as a proof that a desire for 
scientific knowledge is steadily increasing, and therefore have much pleasure in 
eee it to our readers. Many of its articles will be found of much 
interest. 
