NOTES AND QUERIES. ERE 
THE New Sarety StTacE.—Mr. Aylward is also making the 
new safety stage, which was described in a recent number of the 
Journal of the Royal Microscopical Society. It is an adjunct no 
Microscopist who exhibits at soirées should be without. 
THE USE OF DiapHRAGMS.—Pritchard says “when day-light is 
used (which can never be rendered equal to artificial light, by any 
arrangement, at least for lined objects, with any sort of instrument), 
vision is much improved by the use of diaphragms; these, however, 
are inert unless the image of them in the visual pencil is less than 
that of the aperture of the object glass or magnifier with which 
they are used. 
PRESCRIPTIONS AND RECEIPTS.—M. Vogel points out that in 
the use of gelatin bromide the addition of an aqueous solution of 
Chrcme-alum to the developer prevents the wrinkling of the film 
from the action of heat. To tcoc.c. of the developer he adds 
2c.c. of the solution without impairing the sensitiveness. He 
recommends this to those who make use of gelatin-brcmide in 
warm climates, and also advises them to immerse the plate as soon 
as developed for two or three minutes in a saturated aqueous 
solution of common alum.—/. de Fhot. et de Mic. 
Le Bulletin Belge (1880, No. 10) publishes under the name of 
Dr. Stolze the following prescription for a developer, “ which gives 
to the image an extreme delicacy and softness,” and “has the 
advantage of being under the constant control of the operator.” 
Sulphateroflrons: 229. cnt 7 Se hie: 5 grammes. 
Sulphate: of COppen:. W858. 5. Gate 2 i 
SSP SREES Br EGE SES ie Sedaris doe ee I #3 
Glacial Acetier Acid a) Ri csnod coed seoese Tee 
ieoimiwater 6 2o. eee Ik es Ae TOO ls; 
When all is dissolved the solution is to be filtered. 
This developer bears a great resemblance to one of Captain 
Abney’s, which I mentioned in the Annual of the Journal for 
1877. It differs from it only in the addition of sugar, and the 
suppression of alcohol. Apropos of this I would point out that 
in the prescription as given by me the printer has put 100 c.c. 
instead of 1,000 c.c.—/. de Fhot. et de Mic. 
Amateurs and artists are strongly prepossessed in favour of Dr. 
Vogel’s emulsion, which, for rapidity, is said to be second only to 
the gelatin-bromide. The composition is kept secret by its dis- 
coverer, but the Bul. Soc: fr (1880, No. 11) gives the following 
receipt :—‘“‘ 14 grammes of common gelatin emulsion, well dried 
in alcohol, are dissolved in 14 c.c. of glacial acetic acid, at a 
temperature of from 30°c. to 35°c. Then are added, in small 
quantities, and with constant stirring, 28c.c. of a mixture of } 
