ηπτΜ
BETHLEHEM PLURO STOPPER
for Laboratories
and Glass Shops
ONE PLURO STOPPER EQUALS 17 STANDARD STOPPERS Provide vacuum tight fit for all size openings — 22 mm to 100 mm. An ideal bushing be•^ tween tubing, bottles and other glassware. FOR GLASSBLOWING. One stopper will fit every size tubing ranging from 22 mm to 100 mm. Can be used for plug or air vent with swivel and blowhose. Cat. No. RS2A Black Rubber $3.95 ea. Cat. No. RS2B Neoprene (sulphur free) $4.55 ea. Available from your laboratory dealer or direct
BETHLEHEM Apparatus Company, lnc. HELLERTOWN, PENNSYLVANIA
refrigerated centrifuge T h e Model LR features a new design refrigeration system which employs forced a i r circulation t h r o u g h side and bottom cooling areas to provide a continuous laminar flow of cool air streams onto all portions of t h e rotor. Chamber temperatures may be set as low as —15 C and automatically maintained w i t h i n — 1 C. Rotor compart ment temperatures are easily maintained at 0 C a n d lower, even d u r i n g runs at m a x i m u m speed for extended periods.
FOUR
Instrumentation includes a continuous reading electric tachometer, t w o hour timer, automatic temperature con troller, variable speed controller, ammeter for rotor accele ration control and various o p e r a t i n g safety controls. A full 1 H p . Universal motor provides direct power to any rotor employed, without the use of cumbersome high speed attachments, pulleys o r gears. All rotors are inter changeably used in both refrigerated and non-refrigerated Lourdes' centrifuges without the use of special adapters. Mure compact and competitively priced, the Model I.R offers highest quality construction, m a x i m u m operating efficiency and unsurpassed performance.
INTERCHANGEABLE
__
CAPACITY (M«0
Τ Λ Ο R O T 0
*
1 1 " Angle 9 " Angle 9" Angle Swinging Cup
1 ,500cr_ 4G0cc 360cc 9occ
(OK250CC) (8x50ccl (24x 15ct.) (8x12cc)
ROTORS RPM (Max.)
RCF χ G (Max.)
11,000 15,300 1 5,300 12,000
20,000 30,000 30.000 21,500
Backed by over a decade of laboratory instrument manufacturing experience, each LOURDES' unit is guaranteed for a period of one year.
NOTE· Adapter:, availab'î; for smaller l u b e s
LOURDES
INSTRUMENT
53rd STREET and 1st AVENUE LARGEST
MANUFACTURER
·
CORP.
BROOKLYN 32, Ν. Υ.
OF S U P E R - S P E E D
W R I T E FOR LITERATURE. REFER T O AC97
CENTRIFUGES'
For further information, circle number 64 A-2 on Readers' Service Card, page 99 A
64 A
·
ANALYTICAL CHEMISTRY
Infrared: A Library of Congress Bibli ography, P a r t I I . M. W. Ayton and others. Office of N a v a l Research. 156 pages. Order P B 111643, Office of Technical Services, U . S. D e p t . of Commerce, Washington 25, D . C. March, 1957. $ 3 . References to unclassified reports and documents issued from 1931 t o 1952 are included in this bibliography. T h e list was compiled from a search of files of 17 American a n d British governmental agencies a n d American universities. All material concerned with scientific aspects of infrared radiation a n d its effects h a s been covered. Also included are all technical applications except i t s use in industrial heating a n d drying processes. Die Cerimetrie. Walter Petzold. vii + 340 pages. Verlag Chemie, G . m . b . H . , (17a) Weinheim/Bergstr., G e r m a n y . 1955. D M 2 0 . 8 0 .
For further information, circie number 64 A-1 on Readers' Service Card, page 99 A
Model LR
NEW BOOKS
Here is a compilation of t h e develop ments made in t h e last 25 years in the field of cerimetry a n d utilization of ferroine a s volumetric redox indicator. W i t h o u t special emphasis o n theory, descriptions a r e given of ferroine a n d other solutions used as redox indicators in cerimetry, necessary a p p a r a t u s , and numerous methods of determination of inorganic a n d organic substances o b tained from t h e literature available. A comprehensive subject index is included, as well as a list of t h e literature cited. Instrumental Analysis. Paul Delahay. xi + 384 pages. T h e MacMillan Co., 60 Fifth Ave., N e w York 11, Ν . Υ . 1957. $7.90. A discussion of important methods of instrumental analysis n o t generally covered in physics a n d physical chemis t r y courses is t h e chief topic of this book. I n t e n d e d for graduate a n d under g r a d u a t e students, t h e theoretical ex planations a r e elementary a n d illus t r a t e d with simple diagrams. Potentiometry, polarography, emis sion spectroscopy, a n d absorption spec t r o m e t r y are treated a s chapters essen tial t o a n abridged course o n instru mental analysis. F u r t h e r chapters on electrode potentials, amperometric and voltammetric titrations, electrogravimetry ; fluorometry, R a m a n spectros copy1, a n d mass spectrometry a r e in cluded for a more lengthy a n d detailed course. Nuclear radiation methods are also covered, as well as x-ray methods. A section is devoted t o laboratory work, with emphasis on verification of features of t h e various instrumental methods described rather t h a n applica tion of t h e methods t o analysis of materials.
