V O L U M E 2 0, NO. 11,. N O V E M B E R
33 A
1948
Now—anyone can make accurate determinations with a
'«cï\$£\\cfc WHATMAN Filter Paper No. 41Η For Gelatinous or Coarse Precipitates For Iron and Aluminum Hy droxides, Pig Iron Silica, Proteins, in fact for any precipitate where an open, rapid filtering ashless filter paper is indicated, W H A T M A N Filter Paper No. 41 Η should be used. In addition to its other qualities, it has been hardened with acid so that it is almost unbelieveably strong when wet, can be washed vigorously without pulp ing and is especially valuable for determinations where the precipi tate is dissolved and refiltered through the same paper.
2#*2z Designed to measure both
DIFFUSE
REFLECTION
(whiteness,
bright·
ness, color) and SPECULAR REFLECTION (shininess, gloss) A c a r e f u l l y constructed a n d h i g h l y versatile instrument f o r f a s t a n d accurate d e t e r m i n a t i o n s on solid surfaces o f every descrip t i o n , p o w d e r s , pastes a n d o p a q u e liquids. To the basic i n s t r u ment can be a t t a c h e d a n y o f a n u m b e r o f search u n i t s , each e n g i n e e r e d especially for one o r more specific purposes. •
Paper
•
Detergency
brightness tests
•
Paint gloss tests
•
Line or battery operated models
•
12 i n t e r c h a n g e a b l e search units
tests I
A variety of color filters available, in· eluding those for ICI Tristimulus values.
To increase rapidity of filtration of gelatinous precipitates, the use of ashless pulp made from W H A T M A N Ashless Tablets or Accelera tors is recommended.
( '
PLENTY
J
SLICK IN \ APPEARANCE. TOO! .
For those who prefer a soft paper, No. 41, with similar speed and retentiveness to N o . 41 H but nut acid hardened, is the choice. W H A T M A N Filter Products are immediately available from all dealers in laboratory supplies. Samples cheerfully supplied.
H. REEVE ANGEL & CO., INC. 52 Duane Street New York 7, Ν. Υ.
W H A T M A N ' mniJERl^PERS
MURGATROYD 2428/3 — R e f l e c t i o n Meter Model 610, for 110 volt. 60. cycle, A C . Current $120.00 2428/19—Some as 2428/3, but for 6 volt storage battery oper· ation. Without battery... 105.00 2428/32—Same as 2428/3, but for either 110 volt 60 cycle A.C. or 6 volt storage battery opera· tion. Without battery 13S.00
2421/12—6 volt s t o r a g e batlery % 17.00 2428/4 — S e a r c h unit for gen eral use, w i t h green tristimulus filter SS.00 2428/5 —Search unit for paper brightness t e s t s , w i t h built-in Wratten filter # 4 9 45.00 2428/8 — S e a r c h unit for 60° gloss tests 65.00
Write for Full Information on These and Other Units
SCHAAR & COMPANY Complete Laboratory 748 W. LEXINGTON STREET
Equipment CHICAGO
7
