18 A A N A L Y T I C A L C H E M I S T R Y

Α. Η. Τ. CO. SPECIFICATION

R U B B E R S T O P P E R S H R - 1 0 8 AGAIN AVAILABLE FOR IMMEDIATE SHIPMENT FROM OUR STOCK

8806. Vertical cross-section show­ing recessed top of semi­

solid stopper

8807. Vertical cross-section show­ing one Hough fusiform

opening

8808. Vertical cross-section show­ing two Hough fusiform

openings

RUBBER STOPPERS HR-108, A. H. T. Co. Specification. Made of a bloomless, black, heat-resisting composition with low sulfur content and superior aging qual i ty .

The stock possesses great elasticity, contains more than 70% pure virgin gum, is free from surface sulfur and contains less than 0.75% free sulfur; no reclaimed rubber is used. Will withstand temperatures up to 110°C and laboratory tests indi­cate a useful life approximately five times that of ordinary stoppers.

The semi-solid stopper is recessed and offers the advantage of greater depth of seal, eliminates popping out, facilitates re­moval, reduces time required for special boring and requires less rubber than the usual solid stopper. The recess also forms a well for lubricants when using a cork borer.

The design of the one and two-hole stoppers, in which the usual cylindrical bore is replaced by fusiform openings with funnel tops, is the result of the invention of Mr. A. T. Hough, formerly of Paris, France. They offer the advantage that tubing can be inserted more readily and with greater safety than in the usual openings — particularly by students. The fusiform openings permit the insertion of larger tubes than is possible with the usual openings as, for example, porcelain funnel stems up to 14 mm diameter can be inserted in sizes 5 to 8, inch, without special boring.

HR-108 Stoppers are not sold by weight and, because of the low specific gravity and the new design, contain approximately 25% more stoppers per pound than stoppers usually offered for laboratory work. 8806. Rubber Stoppers, HR-108, Α. Η. Τ. Co. Specification, Semi-Solid, as above described, standard length, with recess in top 13 mm dsep in

sizes up to H i / , inch, 15 mm deep in sizes 12 to 13>/· inch, and 19 mm deep in sizes 14 and 15. Size number 00 0 1 2 3 4 5 S'A 6 6>/i 7 Diameter of recess, mm 7 8 9 10 12 12 12 14 16 18 20 Number in 1 lb 160 109 89 70 57 44 37 32 29 27 23 Carton contains 168 108 96 72 60 48 36 36 30 30 24

*Per dozen Size number Diameter of recess, mm. Number in 1 lb Carton contains

.50 .56 .60 67 .75 .85 1.00 1.01 1.10 1.19 1.37 8 9 10 10'A 11 11Ά 12 13 13 Ά 14 15 22 24 27 29 31 34 36 38 42 54 63 18 16 12 11 10 9 7 6 4 . 4 2 . 5 1.9 18 18 12 12 9 9 6 6 4 3 2

8807.

*Per dozen 1.S7 Ditto, One-Hole, with one Hough fusiform opening with funnel top.

diameter from 7 to 10 mm. Size number Number in 1 lb Carton contains

1.79 2.17 2.49 2.66 3.08 3.81 5.16 5.72 8.Π 10.78

Mirimum diameter of opening varies from 3 to 5 mm; max.mum

*Per dozen Size number Number in 1 lb . . Carton contains.

*Per dozen

oo 0 1 170 111 97 168 108 96

2 74 72

3 55 60

4 44 48

5 37 36

5 Ά 31 36

6 27 30

6>/J 24 30

.64 .71 .77 .84 .94 1.05 1.12 1.22 1.31 1.40 7 8

20 16 24 18

9 13 18

10 10 12

10Ά 9

12

11 8 9

l l 'A 7 9

12 6 6

13 5 6

1.59 1.77 2.02 2.41 2.75 2.93 3.35 4.10 5.74

8808. Ditto, Two-Hole, with two Hough fusiform openings, each with funnel top. Minimum diameter of opening varies from 3 to 5 mm; maxi­mum diameter from 4 to 10 mm. Size number 00 0 1 2 3 4 5 5'A 6 6'Ά Number in 1 lb 169 110 95 74 55 46 38 33 28 25 Carton contains 168 108 96 72 60 48 36 36 30 30

*Per dozen Size number. . . . Number in 1 lb. . Carton contains.

*Per dozen

.73 .79 .84 .91 1.01 1.12 1.20 1.30 1.39 1.49 7 8 9 10 IO1/2 11 11 "A 12 13

20 17 14 11 9 8 7 6 5 24 18 18 12 12 9 9 6 6

1.69 1.86 2.10 2.53 2.86 3.24 3.46 4.21

* Price ing

rice for less than carton quantity: 10% discount in carton containing quantity indicated, with additional discounts in larger quantities vary-from 5 % for lots of 6 cartons to 30 % for lots of 48 cartons.

ARTHUR H. THOMAS COMPANY RETAIL — WHOLESALE — EXPORT

LABORATORY APPARATUS AND REAGENTS WEST WASHINGTON SQUARE, PHILADELPHIA 5, PA., U .S .A .

Cable Address "Balance ," Philadelphia

6.06