100 
rOPULAR SCIENCE REVIEW. 
logy is tliiis shown between the carbonaceous matter of meteorites and that 
of organic origin on the surface of the globe. 
The Errors in the Measiirement of the Temperature of the Solar Radiation 
hy the Black-Bidh Thermometer. — In consequence of the diathermancy of 
black glass, of which black-bulb thermometers are usually constructed, 
Mr. It. L. J. Ellery has compared the indications of one of the ordinary 
black-bulb thermometers with another thermometer with its bulb coated 
with lamp-black. These thermometers read the same in the shade, and as 
ordinary thermometers w^ere accurately intercomparable. In the sun, the 
coated bulb always attained a higher temperature than the other, and the 
difference was found to vary with the temperature — the greater the tempe- 
rature the greater the difference. For example, when the coated bulb 
thermometer indicated 77*3°, the black-glass bulb one indicated 70°; when 
the former indicated 155*7° the latter marked only 140°. Part of this differ- 
ence Mr. Ellery points out must be due to the polished surface of the black 
glass bulb reflecting many rays, which are absorbed by the dead surface of 
the blackened bulb. — Trans, of Roy. Soc. of Victoria^ pt. i. vol. ix. 
PHOTOGRAPHY. 
Use of Printing Press to Photographers. — In the Photographic News for 
December II, Mr. Thomas Gulliver recommends the use of the printing 
press to photographers for the purpose of printing their own circulars. 
Removal of Silver Stains from the Hands. — The same journal gives the 
following receipt as better than that recently recommended by Mr. Carey 
Lea : ‘‘ Put half a pound of glauber salts, quarter of a pound of chloride of 
lime (the sanitary disinfectant), and 8 ounces of water, into a small wide- 
mouthed bottle, and, when required for use, pour some of the thick sediment 
into a saucer, and rub it well over the hands with pumice-stone oi a 
nail brush, and it will clean the fingers quite equal to cyanide, but -without 
any danger. This will do to use over again until exhausted, and should 
Ikj kept corked up. The disagreeable smell may be entirely avoided by the 
lil)cral use of lemon juice, which not only removes the smell, but whitens the 
hands. Rotten ones may be used, and answer well.” 
Carrier's Sensitive Alhumenized Paper has thus been reported on by one of 
our contemporaries, whose editor had recently received a sample from Mr. 
Solomon. The specimen had been prepared nearly twelve months: ^^AVe 
found it perfectly unchanged in all respects, -vNuthout a trace of discoloration; 
and printed and treated throughout side by side with that just received from 
Mr. Solomon, there was no difference in result, both being perfectly clean and 
pure. The unchangeable character of this sensitive paper is thus proved 
}>eyond a question. Its qualities remain just the same as we before described 
them. It gives an exquisitely delicate and soft print, but lacks a little 
vigour, unless a negative with full contrast be employed. A special toning 
bath is recommojided, which wo before tried with success; this time we used 
an old sulphocytQiide of gold bath, made some months ago, with perfectly 
good re-*iflt4i.” 
