FLEXIBLE ANALYST'S C O L U M N
NALGON
methods generally under one of three criteria: (a) Numerous samples of one kind are encountered and a conveniently written method would be economical; (b) no standard method is available; and (c) special requirements of the tariff act re quire modification of an existing method or a completely new method is needed.
WRITE
PLASTIC
Generous 3 ft. SAMPLE TODAY! TEST it for soft flexibility clear, water-white transparency unusual chemical resistance remarkable resistance to yellowing with age
Most customs laboratory methods are tested by an interlaboratory test proce dure conducted by the methods committee where identical or specially modified samples are sent to each customs labora tory for test. These test samples are usually forwarded in triplicate to be run on different days. The results are con solidated and treated statistically to deter mine the within- and between-laboratory variation. The information gained from this interlaboratory test procedure is used in evaluating t h e precision and accuracy of the methods.
s
Customs methods in general are not published, although a few are available in Treasury Decisions, Bureau of Customs circular letters, and Customs Regulations. Most of the methods may be made avail able in limited quantities gratis to individ uals who apply to the Division of Technical Services, Bureau of Customs, Washington 25, D . C. The Bureau of Customs Sampling Guide was issued in 1938 as a confidential booklet designed for use of customs officers only. I t has since been declassified, and the material therein m a j ' be available to interested persons. There are 16 specific sampling methods contained therein, covering from 400 to 500 named items in addition to numerous items by reference to class of compounds or materials.
VOLUME
2 7, N O . 6, J U N E
1955
TEST it for every use requiring a soft, flexible superior tubing with dimensional stability
Oimilar actual tests are proving, every day, that new, waterwhite Nalgon is truly an outstanding tubing . . . for Nalgon is formulated from the highest grade polyvinyl chloride and the latest plasticizers to make it a superior tubing . . . at a very interesting price !
The
NALGE CO., Inc. ROCHESTER
2, N E W
YO RIT""···
For further information, circle number 13 Α-Ί on Readers' Service Card, page 39 A
The Bureau of Customs Gauging Man ual of 1941 was issued primarily to instruct customs officers in the methods for deter mining the capacity of casks, cylinders, tank cars, and large storage tanks and in cluded methods and tables for determining quantities of distilled spirits with the use of the gaging rod. I t also included methods and tables for determining the quantity of petroleum products, molasses, and oils in large tanks. Another series of unpublished articles which may be of interest is the weighing methods used on certain imported com modities. These are published in the form of bureau circular letters and may be made available in limited quantities to interested persons. Among the items covered are the so-called scientific weighing methods for raw sugar, bales of staple rayon, refined sugar, tanning extracts, tobacco, burlap, and wool. For the most part these meth ods are used exclusively by customs to "calibrate" weights furnished by the .importers or public weighers, or on in voices. Generally, weighing is performed b y selecting a minimum number of bales, bags, or individual containers and com paring the customs weight of these bags with the foreign weight on the same item. With a minimum number of comparisons, a conversion factor, correct within sta tistically controlled limits, is used to con vert a total foreign or the public weigher's weight into a customs weight, which is then used for duty purposes. By the use of these methods valuable time in unloading steamships and handling merchandise is saved, and the final weights obtained are considered as good as or better than the formerly used 100% weighing by customs.
FOR
OHAUS
TRIPLE BEAM BALANCE
STAINLESS ^»H PLAHmd BEAM? widest selection
•
BEAM CALIBRATIONS
•
SENSITIVITY
•
SCALE CAPACITY
·
greatest capacity
MODEL 750-S with metric
for complete information write for brochure
calibrations
OHAUS CORPORATION
SCALE
lOSO COMMERCE AVE. UNION, NEW JERSEY
For further information, circle number 13 A-2 on Readers' Service Card, page 39 A
13 A
