« PreviousContinue »
NEW YORK CITY
YEAR'S NUMBER OF
is the largest and the most important number of a power plant paper ever issued.
The price of a single copy to non-subscribers, is 50 cents. Subscribe now, send us one dollar, and you will receive the New Year's Number and 23 other numbers during 1905.
Let us tell you how you can make money by getting new subscribers. One Dollar a Year. Issued twice a month. Write for free sample copy.
The Engineer Publishing Company 357 Dearborn Street :: Chicago, Illinois
THE VERANT IN USE.
graphic objective; and, on the other hand, the lens is free from any deformation for a diaphragm distant 27 millimeters (1.06 inches) from the nearest lens surface, the rotating center of the observing eye having to be placed at that point.
These different conditions will result in a normal eye view instead of the small photograph, a distant image of the latter being free from any deformation (if the eye be placed at the point of no deformation), and fulfilling the same conditions as to apparent size, shadows, and relative distinctness as in the case of the objects being inspected from the objective of the photographic camera. The impression thus produced by the small photograph will be much more true to nature; and the main consequence will be an unconscious production of a true. image agreeing with the different marks observed. The photograph as observed through the apparatus will therefore produce quite as plastic effects as in the case of being regarded with both eyes through a stereoscope.-DR. A. GRADEN WITZ.
Mention The Technical World.
Dry Battery-Electro-Gilding Bath Question 1: How can I make a pocket dry battery?
Question 2: How can I make an electrogilding bath which gives a red color like 14or 18-carat gold?-J. V. C.
Answer 1: Dry cells are sold at such a low price that it does not pay an individual to spend his time in the manufacture of a cell. A dry battery may be made in the following manner:
A jar of the desired shape is made of zinc; heavy sheet zinc should be used and bent into the required form, then soldered in such a manner that it forms
Spon & Chamberlain a jar. It will be found difficult to solder
Publishers TECHNICAL BOOKS
T. W., Liberty Building,
Twentieth Century Locomotives
ANGUS SINCLAIR COMPANY
Newly Published and is the Best Book on Railway Machinery ever published. Contains chapters on Elementary lessons on first principles; steam and motive power; workshop operations; locomotive boiler construction; compound locomotives; valve motion; machine tools and shop appliances, and on nine other subjects.
PROFUSELY ILLUSTRATED. Contains 670 pages, 6x9 inches. PRICE, THREE DOLLARS
LOCOMOTIVE ENGINEERING Department T, 136 Liberty Street NEW YORK
zinc. All parts where it is desired the solder should stick should be carefully cleaned by scraping, and clean chloride of zinc used as a flux. The zinc should have a brass binding-post soldered to it. The other electrode is usually carbon, and should have a similar binding-post fastened to it.
In The contents of such cells vary. Gassner's cell, the following mixture is used:
Oxide of zinc, I part by weight; sal-ammoniac, I part; plaster of paris, 3 parts; chloride of zinc, I part; and water, 2 parts.
The cell is sealed by means of covering with pitch, or some similar material which will not allow salts to creep. There are many other formulæ for the contents of the cell, which are used with success.
Answer 2: The following solution, recommended for red plating, should be used hot (at the boiling point) with a platinum wire for the anode and with high current density:
Phosphate of soda (crystallized), 60 parts; bisulphite of soda, 10 parts; cyanide of potassium (C. P.), I or 2 parts; neutral chloride of gold, 2 parts; distilled or rain water, 1,000 parts.
First dissolve the phosphate of soda in 800 parts of hot water. When thoroughly dissolved, filter the solution if not clear, and allow to cool. Dissolve the gold chloride in 100 parts water, and the bi
Mention The Technical World.
Compendium of Drawing
A COMPLETE CYCLOPEDIA
For the Library, the Shop, the Student
900 Pages-1,000 Illustrations, Folding Plates, Etc.
REGULAR price, $10.00, reduced nearly
one-half in order to introduce the work. No more comprehensive treatise on drawing ever published. $25.00 would not buy separate volumes covering the subjects.
Practical test questions combine the advantages of a text-book with a Cyclopedia of Drawing.
OSWALD GUETH, M. E., Consulting Engineer, Technical Editor of "Cold Storage
NOT GOOD AFTER FEBRUARY 28th
BOTH VOLUMES sent free on approval (express prepaid). Keep them five days. If satisfactory send $1.00 and $1.00 per month for five months thereafter. Otherwise notify us and we will transfer them absolutely free. They have a permanent utility that makes them a desirable acquisition to every library.
....CUT OFF HERE.
Please send me free, on approval (express prepaid), one Compendium of Drawing, as advertised in The Technical American School of Correspondence, Chicago:
St. and No.
Answer: The pressure at any crosssection of the pipe can be determined by multiplying the head in feet at that section by the factor .433. The greatest pressure on the first 300 feet length of pipe will be that due to the head of 18 This corresponds to a pressure of 7.8 pounds per square inch. The greatest pressure on the last section will be that due to the total head of 55 feet, and is equivalent to 23.8 pounds. By use of the following formula, the necessary thickness of the tube can be determined:
SOLD ONLY ON ITS MERITS WRITE FOR CATALOGUE No 11 AND 10 DAY FREE TRIAL THE MORSE & WALSH CO., TRENTON, N.J.
CORRECT ADDITIONS MAKE EMPLOYEES
If you are interested in any kind of investment, Oil, Mining, Plantation, Industrial, Lands, Stocks, Bonds, Mortgages, etc., send us your name and address and we will send you The Investor's Review for three months free of charge. A journal of advice for investors. Gives latest and most reliable information concerning new enterprises, Knowledge is power. Great opportunities come and go. Great fakes likewise. Get posted before investing Write to-day. INVESTOR'S REVIEW, 1580 Gaff Bldg., CHICAGO, ILL
DXP t = 2X SXE'
in which is the thickness in inches; D, the diameter in inches (96); P, the press
Mention The Technical World.