Pyrolectric Instrument Co. For your reference we are herewith furnishing a list of the precision instruments and accessory items which we offer. Although primarily manufacturers of electrical precision instruments of the highest grade, we have added to our line a few articles of other manufacture in an endeavor to serve our customers with the best products available in each particular field. Your correspondence concerning the following articles is solicited. The liberal Pyrolectric guarantee and our policy of absolute fair-dealing are distinctly to your advantage. If you have never received a binder for our literature, ask for it. There is one for you. The Pyrolectric Bi-Monthly Bulletin is an interesting and unique publication. There is no charge for it. PYROLECTRIC INSTRUMENT CO. ELECTRICAL PRECISION INSTRUMENTS 636-640 East State Street TRENTON, N. J. Resistance Boxes and Wheatstone Bridges The dependability of resistance coils, as regards accuracy and constancy of adjustment, is determined by the manufacturer's experience in their construction. This involves the selection and testing of suitable resistance wire; design of spool; methods of winding and adjusting; and ageing under known and controlled temperature conditions. The design and construction of the switches-plug or dial type on the Resistance Box or Bridge is also of great importance. When you purchase Leeds & Northrup resistance apparatus for your laboratory you do so with the manufacturer's guarantee that all the precautions in manufacture, which long experience has shown essential, are carefully observed. You are further assured that the instrument, whatever it may be, is as accurate as the specifications have stated it to be, and that its design is in accordance with the best practice, consistent with reasonable cost. In short, when you purchase Leeds & Northrup apparatus, you know that you are getting the very best apparatus of its kind. That what we say is not merely "advertising talk" is easy for you to prove to your complete satisfaction. Any scientific laboratory in which electrical measurements are made has on its staff people who know Leeds & Northrup instruments, and who will be glad to confirm our statements to you. Are you familiar with Catalogue S44 on Resistance Leeds &Northrup Company Electrical Measuring Instruments 4901 Stenton Ave. Philadelphia, Pa. ANNOUNCEMENT We are now ready to make deliveries of the New Rotary CENCO HYVAC PUMP Producing a Vacuum of 0.001 mm. For almost two years experimental work has been in progress on the development and manufacture of this new application of the Rotary eccentric principle of pump construction, as a result of which we are able to announce The Smallest, Most Efficient and Most Economical Outfit For Obtaining a Vacuum of 0.001 mm. WHICH HAS EVER BEEN PRODUCED For Complete Descriptions and Prices, send for Bulletin No. 92 S CENTRAL SCIENTIFIC COMPANY 460 EAST OHIO STREET CHICAGO, U. S. A. These balances are especially suited for weighings which require a fairly high degree of accuracy, the sensitivity being 2 mgm. under full load. Capacity is 100 gms.; beam 200 mm. with adjustable screws at both ends; eccentric beam lifting device; plumb bob for leveling; three leveling screws for balance rests; bows 90 mm. wide; pans 80 mm. in diameter. The case is French Mahogany with glass sides and top, sliding door both back and front; the finish is of highly polished brass, lacquered. These balances are being sold at a most unusually low price and bear our guarantee. The supply is limited and if you have use for at least one of them, we urge you to place your order at once. No. 20580 No. 20582 |