TRADE ANNOUNCEMENTS pH Testing by the Indicator Strip Method
Kjeldahl Digestion Equipment
Under the above title. Pfells & Beuer. Inc.. New York City, have issued a six-page folder describing the Wulff pH tester and the procedure followed in its use. The Wulff tester is particularly recommended for its rapidity. economy of test solutions. and its applicability to highly colored, turbid, or viscous solutions.
The U.S. Sloneware Co., 50 Church St., New York City, offers a new pent-tube construction with individual fume hoods (patent pending) as the h a 1 answer to the vital problem of clean, safe, and efficient fume withdrawal. The following are some of the exclusive features of this design: 1. Each flask neck enters an individual fume hood or pent, molded on the manifold tube. 2. Each individual fume hood or pent is self-draining. 3. The fact that the suction holes between the manifold tube and the individual hoods are small, makes it possible to use a small exhaust fan. 4. Flasks are very easily placed in position without danger of breakage, often a serious item of expense. "U. S. Stoneware" Kjeldahls do not require the use of a laboratory hood. Either the rubber-lined or chemical-stonewarelined exhaust fan will completely remove all corrosive fumes without any gases escaping into the laboratory. The chemicalstoneware-lined exhaust fan is particularly recommended for Kjddahl work, the additional cost being amply justified by reason of its longer life. All units can be operated from a lamp socket, the power consumption being very small.
Water Stills Thc Barnstead Still and Sterilizer Company, 21 Lanesville Terrace, Forest Hills, Boston, Mass., has just published a new illustrated bulletin describing the operation and exclusive features of Barnstead Water Stills of single, double, and triple types made in a full range of sizes to furnish from gallon to 5000 gallons per day. These Stills are made for laboratory and industrial service and may be heated by steam, gas, or electricity, Bulletin may be obtained by writing the makers. Assay Balance
Hmry Troemner, 911 Arch St., Philadelphia, announces a new model assay balance. Although many costly features have been eliminated to permit the offer of this equipment a t low cost. the workmanship is of the same high standard that has always Safety with Comfort in New Chemical Goage characterized Henry Troemner balances. This balance (No. 060 and No. 070), together with the new gold assay halance (No. 7X), A new goggle, effectively ventilated hut giving protection from the new silver assay balance (No. 30X). and the bullion balance splashes of dangerous liquids and the impact of flying particles, (No. 185A), is described in a leaflet recently issued by the manu- has been announced by American Optical Company. facturer. The eyecups are molded to fit snugly to the contour of the face and so prevent liquid from entering around the goggle. Air circulates through slots in the Lens rings, through the radial slots Dark Field Optical Systems in the eyecups, and through the perforated side shields. A solid Above is the title of a well-illustrated and instructive little batik plate in back of the side shield is Bared out on the edge pamphlet (15.5 X 23.5 cm., 16 pp.) which may be had upon nearest the lens, permitting air circulation but isolating the eyes application to Bousch b Lomb Optical Co., Rochester, New York. from splashes. The goggle is fitted with Super Armorplate lenses, case hardened, providing maximum lens protection from impact. The Charlotte Colloid Mill The adjustable rubber-covered ball chain bridge, together Under the ahove title the ChemicoUoid Laboratories. Inc., 44 with the adjustable one-piece headband, provides for exact and Whitehall Street. New York City, have recently issued a catalog comfortable fitting to individual workers. and price list (22 X 28 cm., 12 pp.) completely describing, by A folder illustrating the construction of the A 0 Duralite-50 means of blueprints and otherwise, all models of their mill. A Chemical Goggle and desrihing its comfort and safety features list of products upon which the mills operate successfully is also may he obtained by writing the American Optical Company. included. Southbridge, Massachusetts. Blue Line Exax Catalog
For the convenience of those engaged in organized research the Kimble Glass Co., Vineland, N. J . , presents anew catalog and price list (21.5 X 28 cm., 64 pp.) covering the complete line of Blue Line Exax Graduated Glassware, stocked by leading laboratory supply houses throughout the United States and Canada. Quantity prices have been studiously planned so that now even the small laboratory may effect a considerable saving through purchases of glassware in the new smaller cases. Purchases of 5or 10 case lots bring a still further reduction in prices. Air-Conditioning Regulation Anyone interested may have a copy of a new bulletin which has just been issued on the application of electrical thermameters to the "Efficient Regulation of an Air-conditioning System." I n a concise, orderly way, this unusually well-illustrated, 24page booklet tells the owner, the architect, the engineer, and the contractor what each needs to know about electrical thermometers. I t may be had by asking Leeds & Norlhrup Company, 4934 Stenton Avenue, Philadelphia. Pa., for Bulletin 4001.
Continuous Vapor Pressure Recorder The C. J . Tegliobue Mfg. Co. Brooklyn, N . Y . , has obtained exclusive world-wide manufacturing and sales rights for a uew Vapor Pressure Recorder. This device is a development of Industrial Engineers, Inc., of Los Angeles, Calif., under the Kallam patents and will be known as the TAG-Industrial Engineers Continuous Vapor Pressure Recorder. Now, instead of the long delayed results obtained fro& the Reid laboratory test, i t is possible with this recorder to have a continuous record of vapor pressure instantly available. As vapor pressure is the most important single factor in the manufacture, blending, and shipping of light petroleum products, the utility of this device will be appreciated. I t is fully described in bulletin No. 1115 which the company will be glad to send on request. Central Scientific Company Moves The Central Scientific Company wishes to announce that after April 20, 1935, all communications to the main officeand factory should be addressed to 1700 Irving Park Blvd., Chicago. Illinois.
[P. 351 is used twice, here and in the August issue.]
Metal Radio Tubes DuPrene is the trade-marked name for a synthetic rubber made by E. I. du Pont & Nmours & Company. Inc. It resembles natural rubber in strength, toughness, and elasticity but differs from natural rubber in that it can be vulcanized by the application of heat alone, no sulfur being required. Vulcanized DuPrene is more resistant to oxidation than natural rubber and suffers less deterioration in the presence of oils. I t also withstands the action of sunlight better than natural rubber. It is used in preference to natural rubber wberever conditions of service call for arubber-like material morestable than thenatural product. A popular dexription of DuPrene is givenin a small illustrated booklet recently issued by the Rubber Chemicals Division. E. I. du Pont de Nemours & Co.. Wilmington, Delaware. The Romance of Exploration Many a gallant and memorable figure stalks m o s s the pages of "The Romance of Exploration and Emergency First-Aid," a booklet just issued by Burroughs Wdlcme & Co., New York City. In effect, this is a compendious handbook of most of the important achievements in discovery in the last two centuries. It surveysrapidly theamazing histories of Stanley and Livingstone in Africa and also the tragedy of Dr. Mungo Park. Burton and Speke, Grant and Sir Samuel Baker, Emiu Pasha and the Baron Dhanis are other heroes of African adventure to be found in this little volume. Among other dramatic narratives to be found in "The Romance of Exploration" are those of Sir John Franklin and the intrepid fellows who went to the Arctic to find him. Likewise the tale of what happened to Genenrl Adolphus Washington Greely. Peary, of course, Nansen and Andree, Walter Wellman, and Vilhjalmur Stefansson. Naturallv. the accomnlisbments of Admiral Byrd are duly related, as ;ell as those i f Scott and Shackleton, ~ k u n d s e nand , Sir Hubert Wilkins. Here, too, we encounte~the Roosevelts, father and sons. Roy Chapman Andrem and Sven Hedin, the Duke of Abruzzi, and Dr. Alexander Hamilton Rice. One portion of the booklet deals with tbe conquest of Mount Everest and another with the oioneers of aerialnavieation, from Bleriot to Lindbergh. It is onlv natural that the booklet should drive home one salient fac& in all voyages of discovery: the importance of mmpact and reliable medical equipment. It is profusely iuustrated with reproductions of the medical and first-aid equipments carried to the four quarters of the globe by those intrepid souls who matched their skill. strength, anddauntless courage against the malignantforces of nature. The collection of relic medical eauipments which formed a highly interesting part of the ~urrough;Wellcome & Co. exbibit in the Hall of Science at the Chicago World's Pair now may be seen at the firm's Exhibition Galleries in NEW Yurk. Carbon Monoxide, the Killer The rapidly increasing menace of carbon monoxide in industry presents a challenge today that no responsible o5cial can afford to overlook; particularly since it has been shown that practically no industry is exempt from thehazard of thegas. The immediate need is for rapid and widespread W i n a t i o n of d m - c u t information on the habits and toxic d e c t s of carbon monoxide; and on the equipment developed severally to detect its presence, protect the individual, and resuscitate the victim. All of that information is available under one cover in a new publication, "Carbon Monoxide, the Killer" (14 X 21.5 cm., 20 pp.), prepared by MineSajety Appliames Company, Pittsburgh, Pa., manufacturer of a mmprehensive line of approved carbon monoxide protective apparatus. Copies of this publication may be secured without charge by addressing the company direct.
A new line of metal radio tubes, which tests indicate to be of greater continued e5dency of operation than the glass type now in use, has been announced by the General Electric Company. Schenectady, N. Y. Developed in the research laboratories of the company a t Schenectady, these new metal tubes are not only much smaller and more sturdy, but offer many improved electrical characteristics over the conventional tubes of t h y . They provide their o m shielding and this metal shell is a better heat conductor and radiator than glass. They are particularly advantageous in the field of short wave reception, which in the last year or two has become an important part of all radio receivers. The short leads of the tubes pennit greater amplifxation a t the higher frequencies and the more effective shielding insures greater stability. These new tubes are not interchangeable with glass tubes in the present type radio receivers and will make their f i s t appearance in the new fall line of General Electric sets. The engineering contributions which are cited by General Electric as having helped make the metal tubes possible, are: A new, sturdy seal to replace the troublesome and expensive feather-edge type of glass-to-metal seal. Accurately controlled seam, spot, and projection welding for the fabrication of the envelopeor shell. A vacuum-tight means of sealing off a metal exhaust tubulation.
Oiled Silk Laboratory Aprons The Bbssom Manujaduring Co., 79 Madison Ave.. New York City, o f f a laboratory aprons of oiled silk and oiled pongee. The fabrics are manufactured by the General Electric Company, especially for this purpose. They are strong, durable, light in weight, and resist most acids. They contain no rubber and will not stick. Thirteen fast colors are available.
A new Mnishing cream which f n m s an invisible glove, protecting the skin against dirt, paint, and grease, hasrecently been mmmmced bv the Finishes Div*ion of E. I. du Pont & N m u r s & ~ m n p l t t ~ , ~ aisndescribed d in the May b e of Tha Du Ponl Magainc. The new product, which is kmwn as "Pm-Tek," is not a soap, but a cream compounded primarily for protection. and it is daimed to be entirely harmless and non-irritating to the skin. The cresm,when rubbed on the hands, apparently disappears, leaving them dry and free from any feeling of stilines or greasiness. All dirt and grime subsequently picked up can be washed away with running water, leaving theskin soft, clean,and healthy. "Pm-Tek" is being offered as one of the No. 7 Line products. through drug stores, hardware and paint stores, and by auto accessory dealem. The Bennett Balance A new balance that meets the long-felt need for a low-priced balance, sensitive to a few milligrams, and of a design suitable for use by general chemistry students, is offered by R. P . CargiUe, Distributor, 118 Liberty St., New York City. This balance combines the advantages of finest materials,, with a degree of accuracy and a low price that is made passable only by most modem methods of manufacture and quantity production. It is a notable advance in this field. Even beginners can make weighings to a few milligrams in a few moments on this balance. Capacity, 100 grams; sensitivity, 20 milligrams or better. weights; rider weights Polished bakelite base and pan. No 1attached. Convenient size; fits into labmatay drawer.
