; FEBRUARY 22, 1917] NATURE excvii. 
(oe al id 
(os 
e 
Ss WDROCH a, 
Y A Met % 
“MARTINDALE’S 
Pure Chemicals 
Reagents 
and Apparatus 
FOR 
LABORATORIES 
i 
SUCCESS 
If success in your experiment is dependent upon 
the Filter Paper, it may be commanded by the 
use of Whatman Filter Paper. 
AT CLOSEST PRICES. 
PURE ALCOHOL 
80 p.c. strength supplied in any 
quantity to LABORATORIES 
and Medical Practitioners. 
W. MARTINDALE, 
Manufacturing and Analytical Ohemist, 
10 NEW CAVENDISH STREET, LONDON, W. 
*Phones: 4688 Gerrard; 1797 Paddington, 
When writing please mention NaTours. 
For all general filter purposes use Nos. 1-5. 
There are at present Four Acid Extracted 
grades (practically ashless); two more, Nos. 
43 and 44, are in preparation. 
WHATMAN FILTER PAPER 
No. 1. Equivalent to C.S. & S. 595. 
No. 2. Equivalent to C.S. & S. 597. 
No. 3. Equivalent to C.S. & S. 598. 
No. 4. Equivalent to C.S. & S. 604, 
No. 5. Equivalent to C.S. & S. 602. 
No. 30. Hydrochloric acid treated. Low ash, close 
texture. For quantitative work. Equivalent 
to DREVERHOFF 207. 
No.40 A paper treated by both Hydrochloric and 
Hydrofluoric acids. Has less ash than No. 30. 
For very accurate quantitative work. Retains 
finest precipitates. Equivalent to C.S. & S. 589 
(White Ribbon). 
No.41 Treated same as No. 40, but more open and filters 
Gold Medals and Awards, London, 1862; Paris, 1867; Philadelphia, 
1876; Inventions Exhibition, London, 1885 ; 9 Medais, Paris, 1900; 
Grand Prize Franco-British Exhibition, 1908 ; Rio de Janeiro, 1909 ; 
4 Grand Prizes and Gold Medal, Turin, 1911. 
Jas. J. ji Hicks 
(Incorporated with W. F. STANLEY & CO., Ltd.), 
Wholesale Maker of Meteorological and 
other Scientific Instruments. 
more quickly. Not recommended for filtering THE KATA- 
very fine precipitates unless properly precipitated. — 
Equivalent to C.S, & S. 589 (Black Ribbon). THERMOMETER 
No. 42. A new grade, resembling Nos. 40 and 41 in seep ER SR 
(WET AND DRY BULB) 
or Comfort Meter 
Invented by Prof. Lzonarp Hitt, 
F.R.S., showing the atmo- 
S spheric condition most 
Sm See article ‘‘ Healthy Atmo- meoees to good health. 
spheres,” by Prof. Hill, 3 
Nature, April 22, 1915. 
THE ‘INSTANTER’ 
ANEMOMETER. 
Specially Designed for 
chemical qualities, but differing in its physical 
properties, being much harder and extremely 
close m texture. Suitable for use in filter pumps. 
Equivalent to C.S. & S. 589 (Blue Ribbon). 
Nos. 43, 44 and 50, also FOLDED FILTERS and 
FAT EXTRACTION THIMBLES, will be out shortly. 
WHATMAN 
FILTER Papers 
STOCKED BY ALL LABORATORY FURNISHERS. 
In the event of difficulty in obtaining 
supplies or free samples, write to the 
Sole Sales Representatives 
H. REEVE ANGEL & CO., 
15 NEW BRIDGE ST., LONDON, E.Cc. 
NOGNO? Sx One 
Riflemen and Aviators 
Cives the hourly 
velocity of the 
wind AT SICHT. 
Catalogues (state which required), Estimates, and all information free 
= 
alll MNO ULL Mic 8,9&10 HATTON GARDEN, LONDON. 
