Full text of "Journal of the Franklin Institute [electronic serial]"

See other formats

This is a digital copy of a book that was preserved for generations on library shelves before it was carefully scanned by Google as part of a project
to make the world's books discoverable online.

It has survived long enough for the copyright to expire and the book to enter the public domain. A public domain book is one that was never subject
to copyright or whose legal copyright term has expired. Whether a book is in the public domain may vary country to country. Public domain books
are our gateways to the past, representing a wealth of history, culture and knowledge that's often difficult to discover.

Marks, notations and other marginalia present in the original volume will appear in this file - a reminder of this book's long journey from the
publisher to a library and finally to you.

Usage guidelines

Google is proud to partner with libraries to digitize public domain materials and make them widely accessible. Public domain books belong to the
public and we are merely their custodians. Nevertheless, this work is expensive, so in order to keep providing this resource, we have taken steps to
prevent abuse by commercial parties, including placing technical restrictions on automated querying.

We also ask that you:

+ Make non-commercial use of the files We designed Google Book Search for use by individuals, and we request that you use these files for
personal, non-commercial purposes.

+ Refrain from automated querying Do not send automated queries of any sort to Google's system: If you are conducting research on machine
translation, optical character recognition or other areas where access to a large amount of text is helpful, please contact us. We encourage the
use of public domain materials for these purposes and may be able to help.

+ Maintain attribution The Google "watermark" you see on each file is essential for informing people about this project and helping them find
additional materials through Google Book Search. Please do not remove it.

+ Keep it legal Whatever your use, remember that you are responsible for ensuring that what you are doing is legal. Do not assume that just
because we believe a book is in the public domain for users in the United States, that the work is also in the public domain for users in other
countries. Whether a book is still in copyright varies from country to country, and we can't offer guidance on whether any specific use of
any specific book is allowed. Please do not assume that a book's appearance in Google Book Search means it can be used in any manner
anywhere in the world. Copyright infringement liability can be quite severe.

About Google Book Search

Google's mission is to organize the world's information and to make it universally accessible and useful. Google Book Search helps readers
discover the world's books while helping authors and publishers reach new audiences. You can search through the full text of this book on the web

at http : //books . google . com/|

f^arbarli College Uttirarn

FROM THE FUND OF

E. PRICE GREENLEAF

OF QUINCY

Established 1887

SCIENCE CENTER LIBRARY

dfcitized by

Google

Digitized by

Google

Digitized by

Google

Digitized by

Google

' ^k Digitized by CrrOOQlC

Journal
The Franklin Inslilule

DEVOTED TO

SCIENCE AND THE MECHANIC ARTS

Edited by
R. B. OWENS. D.S.O., D.Sc, F.R.S.C.

Associate Editors :

brig. gen. james allen a. e. kennelly, 8c.d. c. p. steinmetz, ph.d.

wilder d. bancroft, ph.d. gaetano lanza, c.e. s. w. 8tratton, 8c.d.

col. john j. carty, e.d. ralph ifodjeski, d.eng. chief con. d. w. taylof, u s.n.

allertons. cushman, ph.d. l. a. osborne, if.e. s. u. vauclain, sc.d.

col. a. s. eve, f.r.s. albert sauvbur, b.s. r. 8. woodward, ph.d.

w. j. humphreys, ph.d. edgar f. smith, ph.d. a. f. zahm, ph.d.

harry f. keller, ph.d. maj. gen. geo. o. squier,ph.d.

Committee on Publications :

GEO. D. ROSBNGARTEN, CHAIRMAN
G. H. CLAMER GEORGE A. HOADLEY W. C. L. EGLIN B. H. SANBORN

VOL. 188.— Nos. 1123-1128

(94th YEAR)

JULY-DECEMBER, 1919

PHILADELPHIA

Published by the Institute, at the Hall, 1 5 South Seventh Street

1919

Digitized by

Google

INDEX TO ADVERTISERS

PROFESSIONAL CARDS, PAGES XIV AND XV

PAGE

American Pulley Co., Third cover page

Bancroft & Brother, Insurance,
PhiUdelphia ziv

Bamett, G. & H. Co., File Works,
Philadelphia . . Fourth coyer page

Bilgram Machine Works, The, Bevel
Gears, Philadelphia xv

Borden, John, & Bro ziv

Borgner, Cvrus Cq., Fire Bricks,
etc., Philadelphia zvi

Bradley Printing Co., Philadelphia. . zv

Chester Steel Castings Co., Phila-
delphia vii

Commercial Photo Engraving Co. . . zvi

Fidelity Trust Co ziv

Franklin Institute, Alumni As-
sociation vi

Franklin Institute, Announce-
ments i

Franklin Institute, Awards
of zi-zii-ziii

Franklin Institute, Certificate
of Membership, Terms and
Privileges z

Franklin Institute, Indices to
Subject-matter and Authors . . . vi

Franklin Institute, Officers
and Trustees ix

Franklin Institute, Journals
for Sale vi

Franklin Institute, School of
Mechanic Arts vi

Hamlin & Morrison, Analytical
Chemists, Philadelphia ziv

rAOB

L.eeds & Northnip Co., The, Electri-
cal Measuring Instruments,
Philadelphia iv

Lippincott, J. B. Company, Pub-
lishers iii

Lonergan, J. E. Co., Oilers, etc.,
PUladelphia ; . vii

McCaffrey File Co. . Fourth cover page

Moore & White Co., The, Paper-
making Machinery ziv

Nice. Eugene E.. Mfr. of Paints,
Varnishes, Fillers, etc zv

Oldach Company, Book-Binding '

Keystone Screw Co. .

viii

Olsen, Tinlus, Testing Machine Co.,
Testing Machines and Hydraulic
Presses yil

PhUadelphiaBobkCo. . xv

Philadelphia Electric Co. ..... zvi

Phosphor Bronze Smelting Co., Phila. ziv

Powers - Weightman - Rosengarten
Co., Chemists iv

RiehI6 Bros. Testing Machine Co. . . ziv

Sadtler, Samuel P.& Son, Consulting
^Chemical Ezperts xv

Sellers, Wm. & Co., Inc., Machin-
ists, Philadelphia v

Troemner, Henry, Scales ....

vii

Underwood Typewriter Co.

Fourth cover page

United Gas Improvement Co. .... ii

Watson & McDaniel Co., Philadel-
phia iv

Weber, F. & Co., Draughting and
Engineering Instruments .... zv

Wiedersheim & Fairbanks, Patents . zv

Wood, Alan, Iron and Steel Co. . . viii

Digitized by

Google

Journal of The Franklin Institute.
THE FRANKLIN INSTITUTE

ANNOUNCEMENTS

MEETINGS

COMMITTBE ON SCIENCB AND THE ARTS. First Wednesday of

each month, 8 P.M. (eicept Jnly and Atignst).
BOARD OF MANAGERS. Second Wednesday of each month, 3.30 P.M.
INSXTTUTE. Third Wednesday of each montii (except June, July

Augost and September), 8 P.M.
SECTION MEETINGS. Thursday Evenhigs (except week of Institute

Meeting), 8 o'clock. October 1 to April 30.

PAGB

Officers for 1919 ....... x

Memberddp ....... xi

Awards and Premiums ...... xil

The Franklin Medal

EUiott Cresson Medal

Potts and Longstretfa Medals

Certificate of Merit

Boyden Premium

Journals and Indices ...... xiii

School of Mechanic Arts . .xiii

CHANGES OF ADDRESS

Members are particularly requested to inform the Secretary
of changes of address.

Digitized by

Google

Journal of The Franklin Institute — Advertisements.

The United Gas Improyement
Company - Philadelphia, Pa.

LESSEES, OPERATORS AND BUILDERS OF

GAS WORKS

largest builders in AMERICA OP

CARBURETTED WATER GAS PLANTS

Sole American Builders of the
Standard Double Superheater
Lowe Water Gas Apparatus.

System for Controlling Air and Gas Analysis Apparatus.

Steam Supply to Water Gas Hygrometers.

Apparatus. Photometrical Apparatus.

Waste Heat Boilers for Water First Aid Kits for Gas

Gas and Coal Gas Appa- Asphyxiation.

^^^^^' First Aid Kits for Electric

Vertical Retort System. Shocks.

Tar Extractors for Carburet- First Aid General Wall

ted Water Gas. Cabinet.

Your courtesy In mentioning the Journal will be appreciated

Digitized by

Google

Journal of The Franklin Institute — Advertisements.

THE LATEST SCIENTIFIC BOOKS

The Chemical Analysis of Iron

By ANDREW ALEXANDER BLAIR
Illiulr«t«d. New eiglitli edition. 8to. 98.00 net

A Short Handbook of Oil Analysis

By AUGUSTUS H. GILL. Ph.D.
Reriaed end enUrsed. Eighth edition. 12mo. 92.80 net

Aids in the Commercial Analysis of Oils, Fats
and Their Commercial Products

By G. F. PICKERING
Many tables. 8to. 92.80 net

Modem Shipbuilding Terms Defined and Illustrated

By F. FORREST PEASE
lUoatrated. 12mo. 92.00 net

The Construction and Maintenance of Vessels Built of Steel

By THOMAS WALTON
Larse 8to. 97.00 net

Present-Day Shipbuilding

By THOMAS WALTON
ninstrated. LmeSvo. 93.80 net

Know Your Own Ship

By THOMAS WALTON
Ninth edition. ReriMd and illuetreted. 12nio. 93.00 net

A Handbook of Briquetting

By G. FRANKE
Trandated by FRED. C. A. H. LANTSBERRY. M.Sc, in 2 vols., eacb conmlete in itMlf
VOL. L-THE BRIQUETTING OF COALS, BROWN COALS AND OTHER FUELS

Nine plates and 228 illustrations in text. Sto. 99*00 net
VOL.IL~BRIQUETTING OF ORES, METALLURGICAL PRODUCTS, Etc
4 plates. 79 illostrations in text. 8to. 94.80 net

Methods of Measuring Temperature

By EZER GRIFFITHS, S.D.Se.
81 illustrations. 8to. 92.78 net

A Manual of Dyeing

By E.KNECHT, CHRISTOPHER RAWSON and RICHARD LOWENTHAL, B.Se.

IIM edition. 2 Tolumes. Vol. I conUins 86 ilhistratioBs, 8 fuU-pave plates, 371 paves

VoL IL 08 iUustrationi, 831 paves. Larse 8to. 2 toIs. 914.00 net

Land and Marine Diesel Engines

By GIORGIO SUPINO
Translated by Ueut^CouMlr. A. a BREMNER, R.N.. and JAMES RICHARDSON, B.Sc. (En*. )

Lond.,A.M.Inst.C.E.
19 plates and 380 illustrations in tbe text. 94.80 net

Steel: Its Metallurgy and Mechanical Treatment

By HARBORD AND HALL

Fifth edition. 1027 pa«es. 84 foldiov plates, comprisinc 118 ficures. Orer 800 iOnsteii*

tions in text, and nearly 80 pbotomicroffraphs of steel sections. 28toIs. 913.80 net

J. B. LIPPINCOTT COMPANY ?S!!iilSSJ

Tonr courtesy In mentioning tbe Journal will be appreciated
ill

Digitized by

Google —

Journal of The Fran kijn Institute — Advertisements.

BOOK-BINDING

OLDACH COMPANY

61 N. SEVENTH STREET, PHILA.

EDITION ....
LIBRARY ....
PUIN AND EXTRA
IDB BOOKBINDINO

%RTENC0.1

^ MEDICINAL
n TECHNICAL

J PHOTOGRAPHIC

l^^

^^DED^^

^ PHILADELPHIA
NEW YORE ST. LOUIS

THE LEEDS & NORTHRUP CO.

ELECTRICAL MEASURING INSTRUME^JTS

ApptfiHu for the meMurement of redstance, capacity and inductance. Temperatuie meararing
devices. Cable testing apparatus. Electrical measurenento laboratories equipped.

4901 STENTON AVENUE

PHILADELPHIA

The McDaniel Improved Steam Trap

DISCHARGES CONTINUOUSLY AND NEVER BLOWS STEAM
WATER GAUGES ARE USED TO SHOW THE WORKING OF THE TRAP

Mnd« Extra Haavy for High Praaaura

We also manu&aure Reducing Valves, Exhaust Pipe Heads. Separatota far Lhrc
and Exhaust Steam. Blow Off Valves. Relief Valves. EJectots. Pump Gatw nws.
etc SEND FOR CATALOGUE.

WATSON & McDANIEL CO., Jit^dilftSr^:

Your courtesy in mentioning tbe Journal will be appreciated
iv

Digitized by

Google

Journal of The Franklin Institute — Advertisements.

PhlMphh, Pa.

LABOR SAVING

MACHINE TOOLS

Boring and Turning Milk DiiUing and Boring Machines
Haning Machines Slotting Machines

TOOL GRINDING MACHINES
DRILL GRINDING MACHINES

Wheel Lathes Axle Ladies

Steam Hammers Sand Mixing Machines

INJECTORS FOR BOILERS

(Locomotive — ^Marine — ^Stationary)

Shafts, Pulleys, Hangers, Couplings, &c.

For Economical Power Transmission
(belt.rope.<;ears)

Tour courtMjr Id nentlonlDg the Joarnal will be appreciated

Digitized by

Google

Journal of The Franklin Institute — Advertisements.

Journal of The Franklin Institute

Th« Inttitato has for lale a Hmlted namber of copies of the earlier Imimi and it prepared U
rapplj orders at the following ratea :

1824 to 1888, InduflTe PiicM on applleatioD

1840 to 1868. inchialTe 82.00 per number

1860 to 1878, InolnslTe 1.60 per number

1880 to 1899. IndoslYe 1.00 per number

1900 to 1909, induaiye 76 per number

1910and later 60 per number

Prices tvbject to cbange without notice

If enbera maf obtain bound volumes of the current issues of the Journal by returoinf their
unbound copies in good condition with 81<90.

INDICES

TO THE SUBJECT-MATTER AND AUTHORS

THE FRANKLIN JOURNAL

AND TMB

JOURNAL OF THE FRANKLIN INSTITUTE

January. i8a6, to December. 1885, Price. |s.oo.
January, 1886, to December, 1895 I -»_! -
January. 1896. to December, .w f ^'^- "*' •""•

THE FRANKLIN INSTITUTE SCHOOL
OF MECHANIC ARTS

MecbanicB, Apprentioes, and Stadente in Indnatrial worke may spend two or
more evenings in the week in learning tlie theory and principles of and best
modem practice in the allied technics.

For further information addrose:

The Franklin Institute School of Mechanic Arts

15 South SoTonth Street

THE ALUMNI ASSOOATION OF THE FRANKLIN INSTITUTE

is always glad to refer inquiries for engineers, draftsmen,
etc., to its members.

Since its organization, the association has received many
such requests and several past graduates of The Franklin
Institute School of Mechanic Arts have been recom-
mended to fill positions. Applications should be made
to the Secretary of the Association at the Institute.

Toar courtesy in mentioning the Journal will be appreciated

Digitized by

Google

Journal of The Franklin Institute — Advertjsements.
■ 1840 Standard of Excellence 1918

HENRY TROEMNER'S

' Assay and Analytical

BALANC ES and WEIGHTS

For AH Sdentifie Vta

Used by the Goverament of United
States, Canada, Mexico, and China

HENRY TROEMNER
No. 911 Arch St., VMladelpMa, Pa.. U. S. A.

TESTING MACHINES '

and

HYDRAULIC PRESSES

We are always prepared to make tests of all kinds

TINIUS OLSEN TESTING MACHIRE CO.
SOO North Twelfth Street, Philadelphia, Pa.

(

J. E. LONERGAN CO.

OIUNG DEVICES WHISTLES

POP SAhEi Y VALVES and

STEAM BOILER APPUANCES IN GENERAL

21 1-213-215 Race Street. PhiUdelphia. Pa.

STEEL
CASTINGS

OPEN HEARTH ^"^.^'SV

^^■^^^^^^^■^^■■■■^^" scriptloDfor
Electrical Machinery, Dredging, Rolling, and
Sugar Mill Machinery, Locomotive, Railroad,
md BHdge Work. etc.

and Bridge Work, etc.

CEMENTATION fJflfi'.^Tn^

■"^■^■^^■^^^^^■■^■■^" sizes, from i lb.
up. Superior for Crank-shafts, Gearing, and
other purposes where great wearing results art
requited.

Correspondence Solicited

CHESTER STEEL CASTINGS CO.

Worb, Cheiter. Pa. Office. 407 Susom St. Phibu. Pa.

Toor eourtM7 In meotlooloc the Journal will be appreclatMl

Digitized by

Google

Journal of The Franklin Institute — Advertisements.

Machine Screws

We carry a large stock of Iron and Brass in the above shown standard heads.
We furnish to order any Special Heads, to sample or drawing.

KEYSTONE SCREW CO., Philadelphia

Office ftod Works: 17th ST. ft LEHIGH AVE.

RICHARD G. WOOD. Pm't

J. R. JONES. Viee-Piet't and Timi.

W. W. LUKENS. Sec> ud A»*t Tnu.
HOWARD WOOD. JR.. A»'t Sk'j

EUaklUhtJ 1826

Alan Wood Iron and Steel
Company

Maaofacturen ol

PIG IRON, BASIC OPEN HEARTH STEEL BILLETS,
BLOOMS, SLABS, STEEL SHEETS

HEAVY SHEARED PLATES

• SPEOALTIES-

LocomodTe Jaeket. Blue AmM«l«cl. Bath Boilar, Gas Holdar, Comtcatad,

A. W. Clean. M. F. Cold RoUed Sheets. Pickled and Cold RoUed Sheets.

Water Pipe and Light PUtes.

"A. W." Diamcod end "A. W." Ribbed Pattern Rolled Steel Floor Plate*

— ^— ^— — — Sixes Furnished on Application

Slr;^?^.: Widener Building, Philadelphia

Tour coarteiy In meDtlonlng the Journal will be appreciated
viii

Digitized by

Google

Journal

The Franklin Institute

Devoted to Science and the Mechanic Arts

Vol 188 JULY, 1919 No. 1

A RECTANGULAR-COMPONENT TWO-DIMENSIONAL
ALTERNATING-CURRENT POTENTIOMETER*

A. E. KENNELLY, Sc.D.,

Professor of Eleclrical Engineering: Harvard University, and the Massachusetts Institute of Technology,

Member of the Institute.
AND

EDY VELANDER, A.M.

It is here proposed to describe the construction, mode of opera-
tion, and use of a special form of alternating-current potentiom-
eter, particularly adapted to telephonic-frequency measurements,
and which gives its readings in two rectangular components of the
voltage measured.

Brief History, — The name '* Electric Potentiometer " was
suggested in 1873, by Latimer Clark, for the instrument which
he described, as serving to measure continuous-current potential
differences, in a paper read in London, January 22, 1873, before
the " Society of Telegraph Engineers,'* the forerunner of " The
Institution of Electrical Engineers.'* This instrument has
remained almost unchanged to the present time, and is one of
the most valuable measuring instruments which electrical engi-
neering possesses.

An early form of a-r. potentiometer was described by Franke
in 1 89 1. It employed a small a-c. generator with two armature
windings mechanically adjustable with respect to a common rotat-
ing field; so that both the relative magnitudes and the relative

♦ Communicated by Dr. Kennclly.

[Note. — The Franklin Institute is not responsible for the statemenu and opinions advanced
by eontributors to the Journal.)

Digitized by

Google

2 A. E. Kennelly and Edy VelaxVder [J- F. I.

phase of the two induced emfs. at one and the same frequency,
could be determined.^

An improved a-c, potentiometer was described by Dr. C. V.
Drysdale^ in 1909. This instrument has come into fairly exten-
sive use. It measures an a-c. potential difference in polar coordi-
nates, over the complex plane; i,e., in size and in slope or phase,
with respect to a certain phase standard. Its readings are there-
fore presented in the general form E/. i^°, such as 1.500 Z 125.3°
volts. Its range, without any auxiliary multiplier, is from o to
1.8 volts in size, and o to 360^ in slope. The range in frequency
which it claims is from 25 to 1000 ~ . The Drysdale a-c. potenti-
ometer has filled a great need for a laboratory instrument capable
of measuring planevector ^ voltages. For many such purposes
its use is invaluable. When, however, the source of testing
current is an oscillator, and not an alternator, there is a difficulty
in using this instrument, because the excitation of the necessary
phase-shifting transformer requires more than 60 watts. When
an oscillator is used as the source of alternating currents, it is
necessary to reduce the power absorbed in the measuring instru-
ments to the lowest available limits. The use of oscillators for
such purposes is steadily increasing. It then becomes imperative
to adopt such a form of a-c, potentiometer as will avoid the use
of an electromagnetic phase-shifting device.

Prof. A. Larsen described in 1910/ a form of two-dimensional
potentiometer, the connections of which appear in Fig. i. It con-
sists of a non-inductive resistance AB, in series with the primary
winding of an induction coil BC. an adjustal)le portion of the

* " Die elektrichen Vorgange in den Fernsprechleitungen und-Apparaten,"
by Ad. Franke, Berlin, 1891. Thesis towards the Doctorate at Berlin Uni-
versity.

' " The Use of the Potentiometer on Alternating-Current Circuits." PhiL
Mag., Vol. 17, p. 402, Mar., 1909; also Proc. Phys. Soc, London, Vol. 21, p. 561,
1909; also The Electrician, Vol. 63, p. 8, April 16, 1909; and Vol. 71, pp. 687-
690, Aug. 1, 1913-

■ " A planevector " may be defined as a geometrically directed complex
quantity in a plane of reference, and subject to the laws of complex arith*
metic, as distinguished from a "vector " which is subject to the laws of vector
arithmetic and is not necessarily confined to a plane. In this paper, the term
*' vector " is used as an abbreviation for " planevector."

* A. Larsen : " Der Komplexe Kompensator, ein Apparat zur Messung von
Wechselstromen durch Kompensation." Elek. Zeitschrift, 13th Oct., 1910,
Vol. 31, pp. 1039-IC41 ; also The Electrical World, Vol. 56, Nov. 3, 1910, pp.
1085-1088.

Digitized by

Google

July, i9ig.] An Alternating Current Potentiometer. 3

secondary winding being connected in series with an adjustable
portion of the resistance AB, so that the vector sum of the resist-
ance drop in AB between Mi and Ki, and the mutual reactance
drop between Mz and /Cg, shall be equal to the planevector p.d.
to be measured, between leads PiP2f as determined by silence in
the telephone.

The construction of a resistance-mutual-inductance poten-
tiometer, on the Larsen principle, was taken up in 19 16, in the
electrical-engineering research laboratories of the Massachusetts
Institute of Technology, by Mr. Alfred E. Hanson, in his thesis

Fig.

Connections of Laraen potentiometer.

work towards a master's degree. In connection with this thesis,*
the new type of potentiometer here described was designed.

New Instrument. — The electrical connections of the new
instrument are indicated in Fig. 2, and are in all essentials the
same as in Fig. i. The resistance OA contains 50 ohms, in short
coils, of la-Ia wire, wound both anti-inductively and anti-conden-
sively, and also a short length of slide wire of 0.5 ohm. The
mutual inductance coil has two equal copper windings, each having
8.8 ohms resistance at 20° C, and 3.9 millihenrys self -inductance.

•"The Design and Construction of an Alternating-Current Potentiom-
eter," by Alfred E. Hanson, September, 1916 ; a Thesis towards the degfree of
M.S. in Electrical Engineering at the Mass. Inst, of Technology.

Digitized by

Google —

A. E. Kennelly and Edy Velaxder.

[J. F. I.

The mutual inductance between the two windings is approximately
3.85 millihenrys. The p.d. to be measured is connected to the
terminals pp\ A vibration galvanometer V.G. serves as the
balance indicator.

Fig. 2.

/o o.sc
"M-a.bs mh.

Diagram of connections in new potentiometer.

Fig. 3 shows the general appearance of the Hanson form of
potentiometer. The dial switches A and B control the resistance
taps; while the slider C, moving over the resistance wire, serves
for a fine adjustment of resistance. The dial switches E, F, and
G, control secondary taps in the mutual inductor, E being for
200 turns per step, F 20 turns per step, and G 2 turns per step.
A fraction of one turn may be added, by turning the handle /, as
will be described later.

The interior of the mutual inductance box is shown in Fig. 4.
The winding is toroidal in form, comprising 41 wooden sectors
of suitable taper, as shown in Fig. 5b. The dimensions of one
sector appear in Fig. 5a.

Each sector is first wound with a primary winding of 50 turns
of No. 21 B. and S. gage double silk-covered copper wire (bare
diam. 0.72 mm.) in 2 layers of 25 turns each. Over this primary
winding is laid one layer of varnished cambric insulation. Over
this insulation is a secondary winding, also 50 turns of the same
size wire, in 2 layers of 25 turns each. In some of the bobbins,
taps have to be brought out from the secondary winding. The
mean diameter of the toroid is 36.8 cm. When all the sectors
are assembled, and connected in series, the winding forms a

Digitized by

Google

July, 1919] An Alternating Current Potentiometer. 5

Fig. 3.

General view of potentiometer.

Fig. 4

Interior of mutual inductor.

Digitized by

Google

A. E. Kennelly and Edy Velander.
Fig. 5a.

[J.F.I.

Details of one sector of the mutual inductor. Dimensions in millimeters.

Fig. 5b.

Plan diagram of toroidal mutual inductor. Dimensions in millimeters..

Digitized by

Google

July, 1919.] An Alternating Current Potentiometer. 7

closed circular solenoid with wooden core, devoid of screws or
other metallic attachments. A wooden disk dd. Fig. 4, serves to
support all the individual sectors in their proper places, when
glued in position at DD. The advantages of the toroidal form of
winding are, first, that the external magnetic field is then negligibly
small, so that the primary current produces no appreciable stray
field in the neighborhood of the apparatus; and second, that with
accurate mechanical construction, the mutual inductance between
the primary winding and the secondary coils should be propor-
tional to their number of turns. One of the individual wooden

Fig. 6.

01 K

Range of impedance covered by the potentiometer, at •» xo.ooo radians per second.

sectors is shown at e, held in a winding clamp. The handle /
connects mechanically, by a spindle, with a single turn of second-
ary winding, situated in a hollow space at the centre of the core,
between two adjacent coil sectors. The range of rotation of /,
between the limits of -90° and +90°, or half a turn, provides the
same total change of mutual inductance as one step in the
lowest dial.

Rectangular Range of Instrument. — Fig. 6 is a rectangular-
coordinate diagram, indicating the range in impedance available
with the apparatus for potentiometer measurement. The resist-
ance 0/? = 5O.5 ohms, and at «= 10,000 radians per second
(/= 1 591 wn), y Mw = y 38.5 ohms. At any other frequency, the
value of the mutual reactance will be varied proportionately.

Digitized by

Google

A. E. Ken NELLY and Edy Velander.

[J.F.I.

Any impedance at <i>= 10,000, wrthin the area ORAX on the
diagram, can be covered by the simple series connection of resist-
ance and secondary winding shown in Fig. 2.

Fig. 7 is a similar rectangular coordinate diagram, indicating
the range in planevector voltage available with the apparatus for
potentiometer measurement. If the r,m.s. current Ip supplied
to the instrument, is o.i ampere, or 100 milliamperes, taken at
standard phase, and also at the frequency of reference (w =
10,000), the voltage that cah be covered in the first quadrant is

Fig. 7.

j.x

>
to

c nc V

■ 6

D.OO >
1/

3
1

^ 5.05 •

C 1

,i ]

Rectangular range of planevector voltage covered at w— 10,000 and I^—o.i ampere.

comprised within the rectangle ORAX, and so the maximum
p.d. within reach of the potentiometer is 5.05 +•; 3.85 volts.
At any other current strengtli, the voltage developed in the
apparatus will be varied proportionately. Any voltage within
the field ABCD, Fig. 7, can similarly be covered at w = 10,000,
and /p = o. I ampere, by suitably reversing either the R or jX
components, or both. These reversals are easily made, by means
of switches ; and k, Fig. 4.

Electrical Connectiotis. — The full connections of the instru-
ment are indicated in Fig. 8. The coil C is the secondary wind-
ing of an oscillator of adjustable frequency, which supplies testing
current to the apparatus. The resistance /?' and the condenser C
are used to adjust the potentiometer current in size and in slope.

Digitized by

Google

July, 1919.] An Alternating Current Potentiometer. 9

The switch ; serves to reverse both R and jX. The switch k reverses
jX separately. £ is a compensating rheostat, so arranged as to
keep the total resistance in the circuit constant, while changing the
resistance between the tapping points. The tinknown p,d. is
connected to the terminals pp\ The vibration galvanometer, by
means of which a balance is secured between the adjusted and
unknown vector p.d,s, is indicated at V,G,

Method of Measurement — The vibration galvanometer is at
first heavily shtmted, and is tuned to maximum response for the
impressed frequency. The correct quadrant to employ is first
found by using switches / and k. Successive adjustments are then
made in R and jX, until the vibration galv^ometer deflection is a

gc5£±4

J c

0.5 ohms.

Detailed connections of the potentiometer.

minimum. The galvanometer shunt is now reduced, and the
adjustments of R and jX repeated, tmtil a sufficiently satisfactory
zero balance has been obtained on the galvanometer.

Absolute and Relative Measurements of P.D. — Two general
methods are available for use with potentiometers such as the
one here described ; namely,

( 1 ) The method of absolute potential differences, secured by

passing a measured constant current through the
potentiometer, which current is taken as of standard
phase.

(2) The method of relative potential differences, secured by

passing a constant, but unmeasured current, through
the potentiometer, whose readings are then uncali-
brated, but which become capable of calibration, by
being compared with the reading across a certain im-
pedance which is maintained as a standard of
reference.
The first method has the advantage that it enables the potenti-
VoL. 188, No. 1 123— a

Digitized by

Google

A. E. Kennelly and Edy Velander.

[J.F.I.

ometer readings to be stated directly in rectangular-coordinate
volts. It has, however, the disadvantage of requiring the meas-
urement of the potentiometer current to an even greater degree
of precision than that aimed at in the potentiometer work.

In most laboratory measurements of alternating pA., relative

Fig. 9.

GROUND

simplified diagraxn'of connections, showing the rectangular potentiometer P arranged for
exploration of the potential distribution over the working circuit W.

values only are required, and thus it is the ratio of two measured
voltages which is of immediate importance. Such ratios can be
determined by the relative method, without the necessity of
measuring the potentiometer current. The absolute method has,
however, to be resorted to, when, as in iron-cored instruments
carrying alternating currents, the impedance is a function of the

Digitized by

Google

July, 1919.] An Alternating Current Potentiometer. 1 1

current strength, and therefore departs from Ohm's law. In all
measurements of p,d. in circuits which obey Ohm's law, the
second or relative method is to be preferred. Both methods of
using the new instrument have been tried.® In the absolute
method, the potentiometer current was measured by a differen-
tial dynamometer.^ This plan was found to work well, although
a considerable amount of care was required for the measurement
of the potentiometer current. In the progress of the experimental
work, however, the relative method was found to be increasingly
advantageous.

The essential connections of the second or relative method are
presented in Fig. 9. The oscillator coil or source of alternating
emf, is marked O. This coil is inductively connected with each
of two circuits; namely (i) the potentiometer circuit P, and (2)
the tested or working circuit W, The P circuit contains the
tuning condenser C\ and the adjustable resistor R\ as well as
the potentiometer abc. The W circuit may contain any set of
apparatus in which potential differences are to be measured. As
shown in the figure, the p,d, at the terminals AD is being led to
the potentiometer through the tuned vibration galvanometer VG.
In the second or relative method of testing, the drop of potential
between terminals B and C on resistance r may be used as the
standard p,d. Then if the device to be tested in the working cir-
cuit is the condenser c, the terminals AB can be connected imme-
diately afterwards to the potentiometer. As will be shown later,
it is important to maintain a gfround connection at the point A,
Consequently, the drop across any single element, such as BC,
is obtainable as a vector difference between that across AC and
that across AB.

Let r be the standard impedance of known slope (which in the case
of a strictly non-inductive resistance would be zero) (ohms Z )
Z be the unknown impedance of the condenser c to be measured
(ohms Z )

Ip be the r.w.j. current in the potentiometer circuit (amperes Z )
/pjrbc the r.m.s. current in the working circuit (amperes Z )
R^ -f jXi the reading of the potentiometer across terminals AC,
Rt-\-]Xt the reading of the potentiometer across terminals AB.' *

• " Alternating-Current Potentiometry at Telephonic Frequencies," by Edy
Velander ; a thesis towards the A.M. degree at Harvard University, June, tOtS.

^" Precfse Measurements of Alternating Currents," by C. O. Gibbon, fiier-
trical World, May il, 1918, pp. 979-981. , .• ^,..'.

Digitized by

Google

12 A. E. Kennelly and Edy Velander. (J- F- 1.

Then the drop across the standard resistance r will be

/p(/?i + yx,)-/p(/e, + /x,)-/p(/2, + /X,)-/Hr.. volts ^ (i)

In the AB connection, we have

/p iR% + yx.) - Ij^Z volts z (2)

Dividing (2) by (i)

T-trf: --"*=^C3)

This procedure assumes that /p remains the same in both
tests, and also ly^. When, however, a high degree of accuracy is
required, this assumption cannot be made. Suppose that in the
first test/'p is the vector potentiometer current, and / '^the vector
working current. Next suppose that when the second measure-
ment is made, both the sizes and the slopes of these currents may
have slightly changed, so that /"pis the new potentiometer cur-
rent, and /'V the new working current. Then rewriting ( i ) and
(2) accordingly, we have

— -J^-^l^/T^ numeric Z (4)

If, however, the potentiometer current and the working current
vary together, so that the vector ratios remain equal :

V w I' p

J77^ "jTTp numeric Z (5)

. Then equation (3) will still hold. If, then, the mutual inductances
between the primary coil, and each of the two secondary coils
/Sl p and ATur remain constant, also the mutual inductance between
Kp and K^ » likewise the impedance in each of these circuits ;
then any variation of current in the primary coil, due to unsteadi-
ness in the oscillator, will not affect the vector ratios of equation
(S), and will therefore not affect formula (3). If, however,
the frequency impressed by die oscillator varies, then the above
reasoning will not hold, and the method will be vitiated. It is
therefore necessary that the frequency should be maintained
constant within satisfactorily close limits. It should be noted
that during OrC potentiometer tests, no appreciable change should

Digitized by

Google

July, ipig.] An Alternating Current Potentiometer.

be made in the load upon the oscillator; because any change in this
load produces some corresponding change in the oscillator
frequency.

Frequency Measurements. — It will be evident from the fore-
going, that careful measurements of the impressed frequency
are necessary in the use of the OrC potentiometer.

Probably the simplest device for the measiu*ement of the
impressed frequency is the Campbell condenser and mutual induct-
ance branch circuit ® of Fig. 10. Here n condenser of C farads
is shunted by the secondary coil of a mutual inductance of M
henrys and a vibration galvanometer VG. One or both of these

Fig. 10.

Campbell frequency-measurinR arrangement.

elements is varied, until the galvanometer shows no current. We
then have, if / is the vector current in the circuit (amperes Z )

jMtoI+I

whence

juC

Vmc'

=0 volts/(6)

.radians /sec. (7)

Strictly speaking, this zero current in the vibration gal-
vanometer can only be secured if (i) there is no effective resist-
ance in the condenser, and (2) no effective capacitance in the
secondary coil. Owing to the great difficulty of securing these
conditions, to the necessary degree of precision, a sharp zero
balance is hard to obtain. The modification of connections shown
in Fig. 1 1 enables this difficulty to be overcome, A large resist-
ance R, of say 2000 ohms, is connected through an adjustable
small inductance I, as a shunt to both the condenser and mutual-
inductance primary. The secondary is led through the vibration

•A. Campbell. Phil Mag,, May, 1908, Vol. 15, p. 166.

Digitized by

Google

14 A. E. Kennelly and Edy Velander. [J- F- 1.

galvanometer to an adjustable tap on the resistance. If the con-
denser current is represented by I cf.m.s. amperes Z , and the cur-
rent in the resistance by I j^ r.m.s. amperes Z , then withF^^r.m.s.
volts Z as the p,d. between A and B, at balance,

Vab
^'^ r+jf^Lu-L"^ amp^esZ(8)

and

^^ " R^ amp^es Z (9 )

r being the effective resistance of the secondary winding in ohms.
The p.d, in the galvanometer circuit will be

jMt^Ic-^kRIj^^O volts Z (10)

where kR is the resistance included between B and the tapping
point. After this zero balance has been obtained, first by assign-
ing k and C, with a final adjustment in M and /, we have

V<'^r)

jii\ radians /sec. (11)

with the further condition that / has had to be adjusted to

l=^CRr(i +^\ henrys (12)

This method enables a sharp balance to be obtained at the expense
of the additional adjustments. Moreover, since i/k may con-
veniently be made a large number, C and M can both be kept
reasonably small, even at low frequencies.

The same connections are presented in Fig. 12, under the
form of a generalized Heaviside bridge. Formulas (8) to (12)
apply equally well to this case.

In both Figs. 11 and 12, a ground connection is indicated in
the frequency measuring set, at the point B. As will be men-
tioned in connection with sources of error in the use of the
potentiometer, the selection of a proper ground point is vital to
the accuracy of the measurements. At frequencies higher than,
say, 100 cycles per second, parasitic alternating currents, due to
distributed capacitance in the apparatus, play an increasingly
prominent part. At very high frequencies, such parasitic cur-
rents may even swamp the working current. Either the point A,
or the point B may be grounded in Figs. 11 and 12; but prefer-

Digitized by

Google

July, 1919.] An Alternating Current Potentiometer. 15

GROUND

Preferred modification of frequency measurer.

Fig. 12.

GROUND

Bridge arrangement of connections in Pig. ii.

Fig. 13.

rnmit-

4-00 VOLTS.

Pliotron connections; skeleton plan of connections.

Digitized by

Google

A. E. Kennelly and Edy Velander.

[J.F.I.

ably B^ owing to the preponderating distributed capacitance of
the mutual inductor.

Oscillator, — ^A convenient set of vacuum-tube generator con-
nections appears in Fig. 13. F is a 3-electrode vacuum-tube of
a pliotron oscillator or similar type, with its plate, grid and fila-
ment. The main oscillation circuit consists of the adjustable
condenser C and inductance L. The grid-coil secondary winding
FG supplies the oscillating excitation to the grid. The secondary

Fig. 14.

SECONDARY
COUPLING
COILS

POTENTIOMETER.

PLIOTRONw
BULb ^

MOTOR

GROUND

Arrangement of the pliotron as a generator.

winding AB may be connected to the potentiometer circuit. Sev-
eral such secondary coils may be used. The continuous emf,
may be supplied by a small dynamo generator. If possible, this
generator should be driven by a motor actuated by storage battery
for steadiness of action. An auxiliary condenser of 2/Lt/ serves
as a high-frequency bridge across the inductance of the generator.
A more detailed set of connections, showing an actual arrange-

/-\

Digitized by

Google

July,i9i9.] An Alternating Current Potentiometer. 17

ment employed, appears in Fig. 14. In this case, 240 volts of
continuous plate emf. was derived from a storage battery, and 160
volts from a generator which was storage-battery-motor driven.

A Vreeland oscillator was also used in the earlier measure-
ments. This apparatus is too well known to need special descrip-
tion. With the Vreeland oscillator employed, the available range
of frequency, without external auxiliary apparatus, was from
400 «/> to 2^00^, With the pliotron oscillator, the available range
of frequency was limited only by the capacitances and inductances
employed in the oscillation circuit.

Vibration Galvanometer. — In nearly all of the measiu^ements
made with the apparatus, a Duddell bifilar vibration galvanometer,
adapted for use up to a frequency of 2000 i^, was employed as
the balance detector. This served the piupose satisfactorily
when properly tuned to the impressed frequency. When p.d.
measurements are made upon apparatus of high internal impe-
dance, al detector of greater sensitivity and corresponding
impedance would be preferable. A pair of head telephones of
suitable impedance were found to work well in such cases. A
crystal detector with d-c. galvanometer was also used successfully.

Example of the Use of the Instrument in a Simple A-C. Cir-
cuit, — ^As an example of the measurements that may be made
with the instrument, we may consider the simple series circuit
ABCDEF in Fig. 15, consisting of a fixed mica condenser AB
of i.o microfarad, in series with an anti-inductive metallic resist-
ance EC of 200 ohms, followed by a non-ferric inductance CD
of 100 millihenrys and 22.2 ohms, followed again by an anti-
inductive resistance DE of 200 ohms similar to EC, and finally
by a second mica condenser EF of i.o microfarad.

The electrical connections for exploring the potentials along
the work series AF, Fig. 15, are indicated in Fig. 9. When
using the absolute method, the differential dynamometer, Dy,
measures the r.w.j. alternating current strength supplied in the
potentiometer circuit, and thus furnishes the voltage scale E = IR
^-jIX, obtained for any reading of R and jX. Fig. 16 shows the
results actually obtained in this way, at an impressed frequency
of 500-^, with a current of 0.020 ampere in the potentiometer
circuit. The grounded point A was kept fixed, and measurements
were made by shifting the lead of the tuned vibration galva-
nometer along the points B, C, D, E and F in succession. These
vector p,d,s are indicated in Fig. 16 by the vectors AB, AC , . .

Digitized by

Google

A. E. Kennelly and Edy Velander.

[J.F.I.

AF, respectively. The straight lines connecting the adjoining
pairs of points BCj CD, DE and EF on the diagram, then become
the inferred vector potential drops in the successive elements of
the circuit, all presented to the particular phase of the potentiome-
ter current as standard.

It will be observed that the lines BC and DE are parallel.
The direction of these lines shows the phase of the current in the
working circuit, assuming that the anti-inductive resistances BC
and DE may be regarded as pure resistances, at the test frequency

Fig. 15

C«l juf.

R«2oo ohm.

L« 0-10 h.
It« 22.2 ohm.

R=2oo ohm.

Simple series circuit explored.

of 5000^. The lines AB and EF on the diagram are also parallel
to each other, and are perpendicular to the lines BC and DE.
This shows that the voltages at the terminals of the condensers lag
substantially 90° behind the current in the working circuit, accord-
ing to the regular theory. The line CD is the drop in the induct-
ance coil, and may be analyzed into two mutually perpendicular
components; namely, D'D in phase with the current, due to the
presence of resistance, and CD' in leading quadrature with the
current, due to the inductive reactance of the coil.

If we replot the diag^m to working-current standard phase,

Digitized by

Google

July, 1919.] An Alternating Current Potentiometer.

as in Fig. 17, we rectify the diagram by a virtual rotation of
approximately 65^ in the clockwise direction. The various volt-
age drops are then read off, to rectangular coordinates, in the
customary manner.

The diagram of Fig. 17 gives a correct presentation of the
voltage drops in each or any series combination of the elements
in the working circuit, provided that the potentiometer current
Ip has been measured. In order to evaluate the impedance of the

Fig. 16.

j VOLTS

i 1 jk

•

""l

L<^

.1 A C .

'-^

0.i

1.5

VOLTS

-J 0.5

Distribution of planevector voltage along series AF, Fig. I5t at 500 cr . to potentiometer
current standard phase.

corresponding elements, it becomes also necessary to know either
the magnitude of /^, the working current; or, the vector impe-
dance of one of the elements. Thus, if the resistance BC is
a standard resistance of 200 ohms, the scale of the entire diagram
can be interpreted in ohms. It should be observed that the
measurement of /p, the potentiometer current, with R and jX, is
insufficient to determine the impedances of the elements in the
working circuit, and that while it would be possible to measure
both Ji7 and Jp, this double operation becomes burdensome and

Digitized by

Google

A. E. Kennelly and Edy Velander.

[J.F.I.

unnecessary, so that the use of the instrimient naturally leads to
the relative method of measurement, in which no current strength
has to be determined, but a standard impedance — ^preferably a
standard pure resistance — is included in the working circuit
Measured potential drops on unknown impedances are then
referred to the measured drop on this standard, as a working unit.

Fig. 17.

j VOLTS
4-O.S

5d 1.

0' . 1.!

> VOLTS

-JO.5

E Iw

'Jl.O

Distribution of planevector voltage in Fig. 16, referred to working current standard phase.

Sources of Error and Their Elimination. — It is impossible
to work for any length of time with any a-c. potentiometer at a
telephonic frequency, without encountering discrepancies in the
measurements, which are attributable to the well-known disturb-
ance from parasitic currents in the distributed capacitance of
the tested apparatus. The first step in the elimination of these
superposed parasitic currents is to ground a suitable point in
the working circuit, so as to bring that point to zero potential,
and prevent the distributed capacitance in the immediate neigh-

Digitized by

Google

July, 1919.] An Alternating Current Potentiometer. 21

borhood of that point from producing a parasitic condenser cur-
rent. In general, the ground should be established at one end
of the range of the elements in the working circuit to be measured.
As an example, Fig. 9 shows a ground established at the point A.
Suppose that the groimd is established at the junction B of two
impedances AB and BC to be compared, such as Z^ and Z^ in
Fig. 18, and that Jp^ is the working current in the absence of
distributed capacitance, and therefore equal in the two impe-

FlG. 18.

W "W

*fe

GFIOUND

Diagram illustrating the effect of improper grounding.

dances. The current i\ in Z^ represents a small parasitic current
of a certain magnitude and phase escaping to ground at B, while
the current i"© in Z^ is a similar small parasitic current which, in
general, will have a different magnitude and phase, also escaping
to ground at B. The resultant working currents in the two
impedances will then be the vector sums {Jw-^-V^ and (Iw-i'^)
amperes, respectively. The ratio of the potential drops in the two
impedances will then be

(Iw-'i"c)Zt

which, in general, will differ from the required ratio, _^ by an
unknoMm amount. ^*

In cases where the quantity to be determined is a potential
difference distribution, rather than an impedance comparison, the
importance of a proper grounding point in the working circuit is
equally great. It is evident that, as a general rule, during a set
of p.d. measurements on the same working circuit, the grounded
point should not be shifted. This is for the reason that when
the ground connection is shifted, the potential of all points along
the circuit with respect to the ground is varied, thereby changing
the entire distribution of parasitic currents.

Digitized by

Google

A. E. Kennelly and Edy Velander.

[J.F.I.

An experimental example of the effect of shifting the ground
connection in a working circuit appears in Fig. 19. Here a
standard resistance box of 100,000 ohms, in 10 series coils of
10,000 ohms each, was inserted in the working circuit, as shown
in Figs. 20a and 20b. In Fig. 20b, the vibration galvanometer
connection to the potentiometer is carried permanently to the
end B of the resistance box. Since it is manifestly inadmissible
to establish a ground connection on this lead, as it would bring
parasitic current directly through the galvanometer, the ground
has to be established at f, the travelling lead to the potentiometer.

Fig. 19.

j MILLIVOLTS

i «PA

J. 150

1 rt\

V'"''

>"-*■■

--<

;/,

^^^^'^

\
\

— ^

5 It

10 ti

fl *

""—i'

iOMLUVOIXS

Distribution of planevector voltai^e along loo.ooo-ohm resistance box. Small circles in-
dicate observed values, crosses indicate computed values, assuming that each section of
the box subtends a hyperbolic angle of 0.08 ^45° hyp. zadian.

This involves, however, a change in the distribution of potential
and capacitance current at each change in the position of T. The
result is shown in the broken curve i', 2', 3' of Fig. 19. The
curve of p.d. between A and B, Fig. 20, should evidently be a
uniform straight line Oio' in Fig. 19. The presence of the
changing parasitic current distribution appears to have been
responsible for the erratic curve shown. Assuming that the pA,
across the entire resistance box is correctly represented by thfe
vector Oio\ Fig. 19, then all of the intermediate* />.rfij should bfe

Digitized by

Google

July, 1919.] An Alternating Current Potentiometer.

situated along this straight line; whereas the actually measured
p.d.s from to the successive points i, 2, 3, etc., Fig. 20b, follow
the bending line i\ 2', 3' . . ., etc.

The connections were then changed to those of Fig. 20a, in
which the ground connection is kept fixed at B, and the travelling

Fig. 20a.

GROUN O

Ezploration by means of the potentiometer P, of the voltage drop along a high-resistance box
A B. of X 00.000 ohms. Note correct position of ground-connection at B.

lead contains the vibration galvanometer. The corresponding
vector curve of p.ds is shown at i, 2, 3, 4, Fig. 19, and is a much
closer approximation to a straight-line vector OA, representing the
p,d. over the entire resistance. This curve resembles in form
that presented by an artificial cable when an alternating emf.,

Digitized by

Google

A. E. Kennelly and Edy Velander.

[J.F.I.

such as OA Fig. 19, is impressed on the sending end, while the
distant end is grounded. The curve indicates that each section of
the box subtends a small hyperbolic angle.

Applications of the New Form of A-C. Potentiometer. — ^A
large field of experimental investigation in the laboratory lies

Pig. 20b.

Incorrect arrangement of ground-connection giving rise to the erroneous results
i'. 2', 3' in Pig. 19.

open to the o-c. rectangular potentiometer. The power it con-
sumes is a fraction of i watt, while its range of voltage is
extensive. It enables the vector p.d, on different parts of an alter-
nating-current instrument, or on different sections of an alternat-
ing-current line, to be measured conveniently. The results are
also of considerable educational value to the student. It is pro-

Digitized by

Google

July, 1919.I An Alternating Current Potentiometer. 25

posed to communicate in another paper a number of the results
obtained experimentally at various telephonic frequencies.*

It should be pointed out that the degree of precision obtainable
with the instrument, although very satisfactory from an alternat-
ing-current standpoint, is not to be compared with that readily ob-
tainable from the d-c. potentiometer. This relatively low precision
is attributable to parasitic currents from distributed capacitance,
and also to stray alternating magnetic fields. If these two sources
of error could be eliminated, the precision of the instrument might
be of the same order as that of the d-c. potentiometer.

Suggestions for Improvements in Construction. — A weak
point in the design of the new instnmient is the relatively high
internal capacitance between the primary and secondary windings
of the mutual inductor, which, at high frequencies, tends to
produce impurity in the vector mutual reactance /X. This defect
could be reduced by increasing the insulating spacing between the
concentric primary and secondary windings on the toroid. At
2000*^, the discrepancy due to this mutual capacitance appears by
measurement, in this instrument, to be (0.25+; 1.2) per cent,
in voltage, but rapidly diminishes as the frequency is reduced.
There is also a weak point in the toroidal form of mutual inductor,
that although there is negligibly small stray alternating field
produced in the apparatus by an exciting primary current, yet
the secondary winding is not exempt from the influence of stray
magnetic fields from external sources at testing frequency. Pre-
cautions should therefore be taken to remove the apparatus from
the vicinity of alternating magnetic fields.

SUMMARY.

(i) The principle of the chc. rectangular potentiometer here
described is not new, but the form of the instrument
appears to be new.

(2) By the use of this instrument, alternating p.d.s can be

measured, to rectangular coordinates, up to at least
2000C0, with only a small expenditure of power.

(3) The use of the instrument shows the marked influence of

distributed capacitance in a^c, apparatus, and the
importance of reducing this disturbing effect when
measurements are made.

* Proc, American Philosophical Society, 1919.
Vol. 188, No. 1123— 3

Digitized by

Google

26 A. E. Kennelly and Edy Velander. [J- F- 1-

(4) The importance of a proper ground connection in the

working circuit is emphasized.

(5) The a-c. rectangular potentiometer escapes the necessity

of measuring the strength of alternating current in
either the potentiometer circuit, or the working cir-
cuit, provided that the relative method is used, and
that the impressed frequency is maintained constant.

(6) Owing to the effects of distributed capacitance, the volt-

age distribution in a simple series resistance box,
carrying alternating currents, fails to follow a vector
straight-line law. The deviation tends to increase with
the impressed frequency.

(7) The importance of reducing the mutual capacitance

between the concentric primary and secondary wind-
ings of the toroidal induction coil, at high frequen-
cies, is emphasized as the result of experimental tests.

Analysis of Statically Indeterminate Structures by the Slope
Deflection Method. M. W. Wilson, F. E. Richart and Camillo
Weiss. (Bulletin No, 108, Engineering Experiment Station, Uni-
versity of Illinois, 1919.) — In recent years rectangular steel frames
with riveted joints have been used, and many types of monolithic
reinforced concrete frames have been developed. The use of stati-
cally indeterminate stresses cannot, accordingly, always be avoided.
Structures are frequently made of an indeterminate type to secure
economy of material. It is felt that analyses of statically indetermi-
nate structures are desirable since such information will do much to
inspire confidence in the reliability and in the economy of such
structures.

An investigation of statically indeterminate structures has been
conducted by the Engineering Experiment Station of the University
of Illinois to obtain a convenient method of analyzing the moments,
stresses and deflections for a number of typical structures. The
analyses were based upon the assumptions that the connections are
perfectly rigid, that the length of a member of a rectangular frame
is not changed by axial stress and that the shearing deformation
is zero. The method has been explained in sufficient detail to enable
the designing engineer to use it in the solution of his problems.
It is believed that the fundamental principles presented may be
readily coordinated with the ordinary principles of mechanics so
that the more complex and even the simpler problems may be
studied from a new viewpoint.

Digitized by

Google

THE PHENOMENA OF DRYING WOOD.*

An Analysis of the Internal Stresses Which Occur in
Wood During the Progress of Drying from the Green
Condition, with a Brief Discussion of the Physical
Properties Which Affect These Stresses.

HARRY D. TIEMANN, M.E., M.F.

Physicist And Dry Kiln Specialist. U. S. Forest Service.
IlTTRODUCTIOir.

But little knowledge exists, either among skilled artisans
working with wood or among scientists, concerning the phenom-
ena which take place accompanying the extraction of moisture
from the green condition to the perfectly dry state. The U. S.
Forest Service has devoted years of study to this subject and
has derived many interesting facts and conclusions, although there
is still much to be learned.

I will attempt to present here a complete summary of the
main facts as far as known, together with a brief attempt to
show the relationship of the stresses mathematically. Just how
the water passes through the wood, from the centre to the surface,
whether by capillary action, flow, or by repeated vaporization and
condensation or a combination of these is still unknown, and I
will not attempt at the present writing to burden the reader with
a discussion of the theory concerning this process. Suffice it for
the present to accept the fact that this action must take place in
some manner in order that a solid block of wood dry. The physi-
cal factors influencing this transfusion of moisture, however, must
needs be considered.

In order to get a clear conception of what takes place during
this transfusion and evaporization of moisture, a knowledge of the
wood substance itself and its relationship to moisture is absolutely
essential. I must, therefore, prevail upon the patience of the
reader by first setting forth as briefly as possible a description
of this complex material with which we have to deal.

* Communicated by the Director of the Forest Products Laboratory,
Madison, Wisconsin.

Digitized by

Google —

28 Harry t). Tiemann. [J- F- 1-

THE WOOD SUBSTANCE.

The substance of which wood is composed being organic is,
therefore, very complex. It is half again as heavy as water, with
a specific gravity of 1.56. It is thought to be built up of small
particles closely laid together, the interstices being capable of
filling up with moisture. The foundation part of this substance
is known as cellulose. Cotton is almost pure cellulose, but in
wood there is another material combined with the cellulose called
lignin. This has never been isolated by itself, but is known only
in combination with other substances. Just how it is combined
with the cellulose is not well known. It adds to the strength
of the cell walls and gives them a color. The elements of which
cellulose is composed are combined in the same proportion as in
starch, to which it is closely allied, although the molecule is
differently arranged. Both are represented by the formula
(CeHioOg)*!, the hydrogen and oxygen being combined in the same
proportion as in water. Sugars, gums, and resins are all closely
related and it is probable that the living protoplasm is capable of
transforming one into the other by the addition or subtraction of
water from the molecule. This accounts for their common occur-
rence in living trees. For example, addition of hydrogen and
oxygen in the proportion of water to the molecule of cellulose
yields cane sugar, 2(CflHio05)+H20 = Ci2H220ii. This con-
version, however, does not take place in the simple manner indi-
cated by the above equation, but the equation is given in order to
show the relationship.

THE STRUCTURE OF WOOD.

Wood is made up of minute cells, arranged somewhat as the
cells in a honeycomb except that the cells in wood are very much
longer in proportion to their width than in a honeycomb and they
are not as uniform. In the " softwoods " (gymnosperms) the
vertical cells are fairly uniform in shape and size but in the hard-
woods (angiosperms) they vary greatly, some being fifty times
as wide as others, the wide ones being termed " vessels " and the
narrow ones " wood fibres." Interspersed between these vertical
cells and fibres and lying in a horizontal radial direction are the
medullary rays, appearing as the *' silver grain " on quarter-sawed
oak. The medullary rays are composed of short, blunt, thin-
walled cells, similar to pith tissue, and are shaped like two-edged
swords set edgewise.

Digitized by

Google

July, 1919.] The Phenomena of Drying Wood. 29

Fig. I.

Microscopic section of a Gymnosperm ("Softwood"), a piece of shortleaf pine (Pinus
echinaia) ; at mnction of two annual rinffs. The vertical lines are the medullary rays (radial).
The centre of the tree is below. A resin duct'D is visible in the "summerwood." Magnified
250 diameters.

Fig. I is a cross-section of a gymnosperm (Pinus echinata),
and Fig. 2 of an angiosperm (Quercus minor), both magnified
the same amount, 250 diameters.

Digitized by

Google —

30 Harry D. Tiemann. [JF- I-

Fig. 2.

Microscopic section of an Angiosperm ("Hardwood"), a piece of post oak (Quercus minor)
at junction of the annual rings. An open vessel or "pore V is shown in the springwood
and a large medullary ray M (radial) on the left. The centre of the tree is below. Magnified
250 times.

THE FIBRE SATURATION POINT.

Water exists in green wood in two forms: As liquid water
contained in the cavities of the cells or pores, and as " imbibed "

Digitized by

Google

July, 1919.] The Phenomena of Drying Wood. 3 1

or hygroscopic water intimately absorbed in the substance of
which the wood is composed. The removal of the free water
from the holes or pores will evidently have no effect upon the
physical properties or shrinkage of the wood,^ but as soon as
any of the " imbibed " moisture is removed from the cell walls
shrinkage begins to take place and other changes occur. The
strength also begins to increase at this time. The point where
the cell walls, or wood substance, become saturated is called the
"fibre saturation point," and is a very significant point in the
drying of wood. In some cases the free water can be readily
removed by heating above the boiling point, but in many cases
this would injure the wood, and as a rule the water contained
within the cells themselves can not be forced out in this manner,
only that from the open vessels or pores (see Fig. 2) passing oflF
in vapor. The chief difficulties, however, come in evaporating
the free water where it has to be removed through its gradual
transfusion through the cell walls instead of by boiling. The
problem arises in the danger of drying the surface below its fibre
saturation point while free water still remains in the interior.
As soon as the imbibed moisture begins to be extracted from
any portion shrinkage begins and stresses are set up in the wood
which tend to cause checking. The fibre saturation point lies
between moisture condition of 25 and 30 per cent, of the dry
weight of the wood, depending on the species.^ Certain species
of eucalyptus, oak, and probably other woods, however, appear to
be exceptional in this respect in that shrinkage begins to take
place at a moisture condition of 80 to 90 per cent, of the dry

*An exception to this statement occurs in certain species, notably in
western red cedar (Thuja plicata) and in redwood (Sequoia sempervirens) ,
in which a collapse of the cell walls takes place in spots or bands during the
evaporation of the free water. This collapse occurs only in excessively wet
regions and when the wood is dried at too high a temperature. The explana-
tion of this peculiar phenomenon appears to be that the cell walls, which are
practically impervious to air while wet, but through which water may readily
pass, become soft and plastic when heated. Under this condition those cells
which are completely full of water to start with are subjected to an internal
suction or tension produced by the depletion of the water in the cavity by its
evaporation through the cell walls. The cells then collapse like rubber tubes,
one layer after another.

* Sec Forest Service Circular 108 — The Effect of Moisture on the Strength
of Wood.

Digitized by

Google

32 Harry D. Tiemann. [J.F.I.

weight. It is possible that this apparent shrinkage may in reality
be a form of collapse.

SHRIRKAGB AND XOISTURB.

Wood in the living tree contains a great amount of moisture,
varying from 30 per cent, in the heartwood of some conifers to
over 200 per cent, of the dry weight in some of the hardwoods.
This moisture must be removed before the wood is fit for use for
most purposes.

Wood shrinks differently in different directions — ^as a rule it
may be considered to shrink twice as much circumferentially as
it does radially and about one-fiftieth as much longitudinally.
Shrinkage continues until this substance is perfectly dry (" oven
dry"), and the wood begins to swell again by absorption of
moisture as soon as it is exposed to moist air. Alternate shrink-
ing and swelling is inevitable with corresponding changes in the
relative humidity of the surrounding air. This causes the so-called
" working " of the wood. Different species vary greatly in this
respect.

Now in the living tree the wood is always above its fibre satu-
ration condition, so that dry wood may be looked upon as in a
unique condition, in that it has never been dry since it was
first formed.

DRYING.

The operation of removing the moisture from wood does not
consist simply of evaporation. This, of course, would be merely
a matter of supplying the necessary heat and removing the excess
vapor. Wood is a complex substance and the removal of the
moisture is accompanied by physical and chemical changes.

In order to pass out from the interior of a board or timber
the water must ordinarily pass transversely from cell to cell and
evaporate from the surface. It is true that it can travel length-
wise very much more rapidly, as is evidenced by the end checking
of lumber, but end drying cannot be counted upon for removal
of moisture from the centre of a long stick. This process of.
transfusion from cell to cell is very slow, so that it takes one-
inch boards from six months to three years to thoroughly air dry,
according to the species, the amount of water they contain when
green, and the conditions of drying, such as method of piling, air
conditions, etc. Even then, unless it is in an exceedingly dry

Digitized by

Google

July, 1919] The Phenomena of Drying Wood. 33

climate, the wood will rarely dry below 12 to 14 per cent. For
thoroughly dry wood this must be supplemented by kiln drying.
Were it not for the unequal shrinkage and the slow. rate of
transfusion of the moisture from cell to cell, the kiln drying of
lumber would present no more difficulty than the drying of wet
cloth or clay. The problem would be merely one of conducting
the requisite amount of heat to thematerial to supply that required
for vaporization, which at 163° F. is 1000 British thermal units
of latent heat plus a small additional amount (about 30 B.T.U.
per pound of dry wood *) required to overcome the attraction of
the hygroscopic material for the moisture. By use of a low pres-
sure or a temperature higher than the boiling point the moisture
would pass off directly in proportion to the quantity of heat
supplied.

PROPERTIES OF THE WOOD WHICH AFFECT DRYIRG.

In the first place let us consider the physical properties of
the material, which must be recognized in order to intelligently
study the drying problem. Different species differ very greatly
with respect to the relative proportions of these properties, but
all possess them more or less.

1. The rate of transfusion of moisture through the wood sub-
stance has already been discussed. It is very slow in some woods,
as oak, and fairly rapid in others, as pine. It is supposed that the
rate is accelerated by increase in temperature.

2. Wood shrinks differently in different directions, and shrink-
age usually begins only when the drying falls below the fibre
saturation point, although with some species, as Eucalypttis glo-
bulus and some oaks, the point is not well defined.

3. Wood substance becomes soft and plastic at high tem-
perature under moist conditions. The effect of temperature upon
plasticity varies greatly with different species, some, as western
red cedar, redwood, and eucalyptus, becoming excessively soft
even as low as 150° or 170° F.

4. Cohesion between the fibres easily breaks down with
increase in temperature in such woods as western larch, and the
southern swamp oaks, thus permitting internal stresses to cause
checking with great readiness.

5. Tendency to warp is due to a warped direction of the fibres.
Cupping of slab cut boards is simply explained by geometrical

"Frederick Dunlap, Forest Products Laboratory.

Digitized by

Google

34 Harry D. Tiemann. [J- F.I.

relations due to unequal shrinkage radially and circumferentially.
6. Wood shrinks more when dried slowly under moist con-
ditions than when dried rapidly, and the higher the temperatures
under moist conditions the greater the shrinkage.

Fig. 3.

Badly honey-combed oak wagon felloes. Produced by too severe casehardening in drying.

7. Excessive drying causes brittleness.

8. Wood absorbs or loses moisture in proportion to the relative
humidity of the air, varying slightly according to the temperature.
This property is known as " hydroscopicity."

Digitized by

Google

July, 1919] The Phenomena of Drying Wood. 35

9. Change of color occurs in some species in drying. This is
distinct from sap Stain or colors caused by fungus or bacteria.
This is notable in hard maple sapwood and in sugar pine. In
the maple, a moist warm atmosphere is conducive to this coloration.

10. Collapse of the cells may occur in some species while the
wood is hot and moist. This collapse is distinct from the shrink-
age which takes place in the wood substance and is due to a
different cause.

These properties of the wood give rise to certain resultant
internal stresses which are the main cause of warping, checking,
and honey-combing (see Fig. 3). " Washboarding " is due to
unequal shrinkage or collapse of adjacent layers of the annual

Fig. 4.

"Washboarding" in an inch board of blue gum (Eucalyptus globulus) due to the alternative
collapse of the annual rings. This board was i)erfectly flat when placed in the kiln as is evi-
denced by the band saw marks running across the surface.

rings of wood and appears on radially sawed lumber (quarter-
sawed). (Fig. 4.)

It is chiefly with the analysts of these internal stresses that this
article has to do.

IRTBRNAL STRESSES AND «< CASEHARDENING."

The term " casehardening " is used to describe the condition
of wood which contains stresses brought about by drying. It is
somewhat ambiguous but commonly used. As the derivation of
the word implies, it signifies in general a hardened case on the out-
side of the wood — derived probably from analogy to the term as
used in metal tempering where the outer surface of the iron
casting is changed to steel. The analogy, however, is not a very
good one and should not be followed too closely.

As applied to wood it is sometimes used to refer to two dif-
ferent, although interrelated conditions. One has to do with the
moisture condition alone, and the other with the internal stresses
resulting from the hardening of the fibres and the relative shrink-
ages. In both cases the wood contains internal stresses brought

Digitized by

Google

36 Harry D. Tiemann. [J- F- 1-

about by unequal shrinkages and a stiffening of the fibres as the
wood dries below its fibre saturation point.

A temporary condition of internal stress may be brought
about merely by a difference in moisture content between the
inside and the surface, which may entirely disappear when the
moisture is equalized provided the fibres have not hardened
unequally. Permanent stresses, on the other hand, may result
from the unequal moisture distribution whenever the outer and
inner fibres become set or hardened at different stages of shrink-
age or under different stresses. In such cases the internal stress
in the wood remains even after the moisture has been uniformly
distributed. This condition is dependent upon the stresses which
exist in the fibres at the time they reach their fibre saturation
point and begin to harden or receive a " set " as it is termed.

There are four variable factors to consider which affect the
result, namely : moisture content of the wood, degree of shrinkage,
internal stress, and period at which the fibres become hardened
or set. Moreover these factors are partly dependent one upon
the other. Temperature is still another factor but may be treated
as an independent variable.

When a piece of wet wood dries rapidly, the outer surface
necessarily becomes considerably drier than the interior. Under
ordinary conditions the outside dries considerably below its fibre
saturation point while the interior of the wood is still in a
green or wet condition. Normally wood begins to shrink at its
fibre saturation point, but inasmuch as the interior of the block
of wood has not undergone any shrinkage, the outer fibres are
consequently held in what might be considered an abnormally
distended condition. Inasmuch as the wood hardens or becomes
stronger as soon as it dries below its fibre saturation point, these
outer fibres may become hardened in this distended condition to
such an extent that if this outer shell were now removed from
the block of wood this shell would no longer shrink down to
its normal condition. In other words, the outer fibres have thus
become hardened or set in such a condition that they will not
subsequently shrink the normal amount.

Let us again consider the block of wood in which the interior
is still wet and the outer fibres have thus become set in this
expanded condition. The outer fibres of the block are then in
tension and the inner ones in compression. As the drying now

Digitized by

Google

July, 1919.] The Phenomena of Drying Wood. 37

progresses the inner fibres subsequently begin to dry and will
tend to shrink their normal amount. The inner fibres, however,
are prevented in turn from shrinking their normal amount by the
hardened, expanded condition of the outer case or shell. The
result will be a reversal of stresses, the inner fibres now being
thrown into a state of tension and the outer into a state of
compression. Now, it may occur under certain conditions that
the inner fibres will also harden in this somewhat expanded con-
dition and the slight residual shrinkage of the outer fibres niay
be sufficient so that when the wood has become uniformly dry
throughout, all of these stresses will disappear. The caseharden-
ing so produced is then of a temporary nature and disappears
upon redistribution of the moisture. In the majority of cases,
however, where rapid drying takes place, the inner fibres, when
they harden up due to drying, remain in a state of tension and
the outer fibres remain in a state of compression from the fact
that the residual shrinkage of the outer fibres is not sufficient
to relieve these stresses. Permanent casehardening therefore
results. The question of whether casehardening is temporary or
permanent is dependent upon the relative degree of hardening of
the outer and inner fibres and the relative amounts of residual
shrinkages when they become uniformly dry.

From a consideration of the stresses which occur during rapid
drying of a piece of wood, it will be seen that the total shrinkage
of the entire block will ordinarily be less in the case of the
severely casehardened wood than it will be in the case of a block
of wood where normal shrinkage of all of the fibres can take place.

It will also be observed that the first stages of casehardening,
in which the outer fibres are in tension and the inner in compres-
sion, will tend to produce external checking if these stresses
exceed the cohesion of the fibres. Secondly, after the reversal
of stresses takes place the result will be that the internal fibres
will tend to be pulled apart by the internal tensile stresses provided
these exceed the cohesion of the fibres. The outer checks, if they
have occurred, will consequently close up due to the compression
stresses introduced in the external fibres by the subsequent shrink-
age of the internal fibres. This condition of internal checking is
commonly called " honey-combing !'

The analysis of the phenomena of casehardening is rendered
complex, on account of interrelation of the four factors mentioned

Digitized by

Google

38 Harry D. Tiemann. U- F. I-

above — ^moisture, shrinkage, stresses, and hardening — since all
these variables must be considered at the same time. For this
reason also the determination of the condition of wood with
respect to casehardening is equally complex.

The method commonly used is to cut a thin disk across a stick
of wood and slot this disk in the form of a tuning fork, but
having, instead of two, a number of prongs. This slotted disk indi-
cates, by the bending of the prongs, the condition of stresses
existing at the time of cutting and also the residual shrinkages
which may take place during the subsequent drying of the block.
For example, let us consider a piece of green wood which is being
rapidly dried and suppose the casehardening disk is cut at a period
when the outer surface has just dried below its fibre saturation
point and the interior is still green, the outer surface being in
tension and the inner portion in compression. The prongs of
such a disk will bend outwardly when cut on the saw, but when
subsequently dried in an oven these prongs will reverse and
bend inwardly, due to the fact that the outer fibre has already
hardened somewhat in the expanded condition so that its normal
shrinkage is less than the normal shrinkage of the inner side of
the prongs.

Again suppose that a disk be cut at a period after the reversal
of stresses when the outside is in compression and the inside in
tension. Such a disk will immediately bend on the saw ; that is
to say, the outer prongs will tend to bend inwardly. Subsequent
drying will only tend to increase the curvature.

It is apparent that there is a period somewhere between these
two at whidi, if a disk be cut, the prongs will neither turn inwardly
nor outwardly on the saw, but nevertheless they will subsequently
turn inwardly when the disk is dried.

In introducing this subject the assumption was made that
the stick of wood was rapidly dried. Ordinarily the more rapid
the drying the greater is the casehardening effect. It will be
evident that this is brought about entirely by the unequal moisture
distribution during the drying of the stick of wood. Were it
possible to extract the moisture from the interior of the block at
the same rate that it is being extracted from the outer surface,
casehardening would not occur either temporary or permanent.
Furthermore it will be observed that the more rapid the drying
rate, the greater will be the factors producing this condition.

Digitized by

Google

July, 1919.] The Phenomena of Drying Wood. 39

These factors will therefore be reduced to a minimum by the
slowest possible method of drying. Consequently, in very slow
air drying of lumber, where the lumber is shielded fr^m both
winds and dry air, casehardening will be at a minimum, other
things being equal. The reason for this is that in very slow air
drying the differential in moisture distribution in a block of
wood is very nearly equalized. There is not produced the exces-
sive differential in moisture between the interior and the surface
which is necessitated by any practicable process of enforced drying.
In kiln drying the aim is to retard the rate of surface drying
by a high humidity in the surrounding medium in order to pre-
vent the casehardening from becoming excessive at any time, but
some casehardening is inevitable. The condition, however, can be
relieved or even entirely reversed as shown in Fig. 8, by subject-
ing the wood to a high humidity and high temperature (steaming)
for a brief time so that the hardened outer fibres are rendered soft
and plastic and yield to the stresses.

ANALYSIS OF STRBSSBS DURING PROORBSS OF DRYING
AND OF CASBHARDBNING.

In analyzing the internal stresses which occur during the
progress of drying a square stick of wood, and the amounts of
" setting " and shrinkage which take place, suppose that in Fig. 5,
p mn represents a disk cut transversely across the stick so that
mn is the centre line. Let half the disk be assumed to be cut
into 8 narrow strips numbered i to 8, strip 8 being next to the
centre line of the disk. For convenience of conception, suppose
that each strip consists of a spiral spring of equal strength
attached to two horizontal bars mn and op, which are so arranged
as to always remain parallel. Let the stresses produced in these
springs be directly proportional to the amounts they are stretched
or compressed from their neutral position. For the sake of the
analogy drying of the wood is to be considered as equivalent to
a shortening (not a compression) of the springs. This shortening
may readily be accomplished by screwing up a nut on the lower end
of each, the ends projecting through holes in the bar mn. If the
springs are all independent, screwing up the nuts will merely
shorten them an equivalent amount, but if they are all fast to
the upper bar op, and only the outer springs are shortened,
these will be stretched or placed in tension, pulling the bar down-
ward and throwing those springs which have not been shortened

Digitized by

Google

Harry D. Tiemann.

[J.F.I.

into a state of compression. This is exactly what occurs when
the outer layers of a block of wood begin to dry below the fibre
saturation point.

Notice now that if the springs be shortened one after another
until all are finally shortened the same amount, the bar op will
merely descend the same amount that the springs have been
shortened and the stresses will disappear. This is what takes
place in a piece of wood when dried without casehardening to a
point where the moisture content is uniformly the same in each
layer. This may be considered as normal shrinkage and is prob-

FiG. 5.

-ir-
D

ably directly proportioned to the amount of hygroscopic moisture
removed. Rarely if ever is this condition realized in drying any-
thing but very thin material.

What generally happens is that the outer layer tends to shrink
in drying but is considerably stretched by the resistance of the
inner layers. Being a somewhat plastic material, it soon hardens
in the stretched condition, so that it no longer tends to shrink
die normal amount. Upon complete drying the inner layers will
tend to shrink their normal amount, but will be slightly stretched
(less so than was the outer layer), thus throwing the outer layer
into compression and the inner layers into tension ; they will also
harden in their slightly stretched condition, but the stresses,

Digitized by

Google

July, 1919.] The Phenomena of Drying Wood. 41

although less than they were at the first stages of drying, may
remain in the wood. The wood is then permanently casehardened.

Going bock to the analogy of the springs. When the outer
spring has been shortened, say half the amount which would
correspond to normal shrinkage, suppose it be annealed and
rehardened, so that without altering its present stress, it then
requires a greater force to stretch or compress it the same amount
as before, and that approximately one-half of the total amount
which it formerly might have been shortened (normal shrinkage)
has already been removed. As the inner springs are then short-
ened in turn the outer " set " spring is thrown into compression
and behaves very much as it would if it had been adjusted back
again to its original length (as though it were resoaked in the
case of wood), although this outer layer continues to be in a
drier state than the inner layers. As a matter of 'fact the outer
layer of wood not only acts as though starting again at its original
length, but it has also become greatly stiffened at the same time.
Here, however, the analysis becomes too complicated to follow
clearly, and we will therefore disregard for the present the increase
in stiffness which takes place in the drying of the various layers,
and assume the springs to remain the same strength.

Having attempted to illustrate the behavior of the wood by
the hypothetical analogy of the springs, let us follow the line of
reasoning a few steps farther. For convenience of reference, let
us assume each spring to be 100 inches long. Suppose the nut
on No. I be screwed up 8 inches, it will be thrown into a state
of tension which will accordingly bring the other seven springs
into a state of compression. The whole bar op will then evidently
be lowered one inch, thus compressing the seven springs each
I inch and stretching No. i a total amount of 7 inches. This is
what happens when the outer layer of a piece of wood dries below
its fibre saturation point, while the interior still retains some
free moisture. Now suppose that No. i becomes " set '* in its
shortened but expanded condition, that is to say, in this position
it no longer exerts the tensile pull which it exerted before, but its
stress is neutral at the i inch shortened position. The bar op
will therefore rise sufficiently to bring about a balance of stresses
and this will cause a new tension in No. i and new amount of
compression in the rest ; No. i is then neutral at 99 inches and not
at 92 inches as when first shortened. In other words, the effect
Vol. 188. No. 1123— 4

Digitized by

Google

42 Harry D. Tiemann. [J. FI-

of shortening it the 8 inches has been done away with and it now
acts the same (disregarding its increased stiffness) as though it
had originally been shortened by one inch. If detached from
the bar it will remain 99 inches in length, and when the disk is
completely dried (all springs shortened 21 inches), it cannot be
shortened its normal amount, as the others will be. Assuming
the normal shrinkage (total possible shortening of the bars) to be
21 inches. No. i having already been shortened 8 inches and being
neutral at 99 inches, it can therefore be shortened only (.99 x 13)
= 12.87 inches. So in the final state, the seven springs will be
79 inches long and No. i will be (99 - 12.87)= 86. 13 inches. (The
total possible shortening of all springs from their original lengths
having been assumed as 21 inches. )

In this way we may analyze the progressive conditions of
the stresses in the eight springs and their corresponding shorten-
ings, corresponding to the progress of drying of the wood from the
outer surface inward and the successive casehardening of the
outer layers, when first separated from the bars, and when finally
shortened the complete amount representing a state of complete
dryness after separation. To make this system of analysis
clearer, let us follow a single case for an example. Let springs
I, 2, 3, 4 each be shortened respective amounts a, b, c, d, by screw-
ing up nuts on their bottom ends, and let the rest remain the
original length of 100 inches. Let D be the distance the bar (?/^
will descend (equals the shrinkage of the entire disk as a whole).
Let n be a factor by which if the distance the spring is shortened
be multiplied it will g^ve the stress existing in that spring, and let
n^ative signs indicate tension and plus signs compression. Then
the following equation will represent the stresses in all of the
springs :

(D-a)n + {D-h)n + {D"c)n + {D-d)n + A{I>-0) = O (1)

Since the summation of all these stresses must equal zero

Now we are at liberty to shorten each spring an assumed
amount (corresponding to the degree of drying out of the succes-
sive layers). For instance, suppose

then the relationship of Z? and c may be calculated.

Digitized by

Google

July, 1919.I The Phenomena of Drying Wood. 43

Substituting in the equation ( i ) :

Suppose Z? = 6 inches then

c «7, 6 = 14 and a -21 inches, and the stresses are No. i = I5n No. 2 =-8n,
No. 3 = -in, No. 4 =0 and each of the others = +6n.

Spring No. 4 having been shortened (shrunken) the same
amount as the bar is lowered will neither be compressed nor elon-
gated and will have no stress.

Suppose now that spring No. i be extended to its original
length by unscrewing the nut on the bottom the full amount
(swelling to its original condition by wetting in cold water or
saturated air). The others remain shortened the same amounts
as before.

Let Z?i be the new position assumed by the bar

81>,=0+2c+c-|-i. 8Z?i=3c+Z?«2i +6 = 27. £>,»=3 3/8
No. I No. 2 No. 3 No. 4 Nos. 5, 6,7,8
+3 3/8n - 10 5/8n - 3 5/8» - 2 5/8» +4(3 3/8)n = O

The stress in No. i has changed to compression, and the
tension in Nos. 2 and 3 has been increased and No. 4 has now
been placed in tension.

Without following further the calculations in detail, the
various relative stresses and the total shrinkages of the disk are
set forth in Table I for several assumed progressive conditions
of casehardening and reabsorption (neglecting the increased stif-
fening of the springs, as explained before).

The first column after " Conditions " gives the shrinkage of
the disk as a whole in inches (a wholly conventional unit assumed
for convenience of discussion) and the next eight columns show
the relative stresses in each of the respective strips. They repre-
sent the actual stresses existing in the disk at the horizontal centre
line mn, ( In the unslotted disk the stresses decrease as the ends are
approached, becoming zero at the end, due to the shearing stresses
between the adjacent strips. )

A careful study of Table I will reveal many interesting facts
and will explain the peculiar and apparently anomalous behavior
of the prongs of the test disk when slotted at different periods of
the drying and when cut into different thicknesses.

The progress of the stresses in the eight layers from the outer
surface to the centre of the stick of wood during drying may be

Digitized by

Google

Harry D. Tiemann.

[J- F. I.

.2 8

.S-o

.SSg .2^

c c . •* c S
•» a - .. •

2^ as

SI
is

S'S ^^ ♦* •2-41

\00

X-f

v«

N»0

:5f

x««

*»

\«0

v*«

«\

«N

is?

NUB
•ON

<*5
1

«*«

\S0

:2t

:5:

f*>

*r>

::?

>*>

O
1

\«8

o
1

•e\

J< 2 *

C/3

« «> SAC'S « ^ , ''^

5 ^"V

^.2

-*>"«

•^^^^^ .

^ O "~ „^
MOO o ^^2;^ «

3 t« "'

u lojx^ uu; ee u 10 o V. M o

"ti '^ "^ tJ

.2-^ ■

CO CO

g.2 S g 8

•C O S «i^-

"• c 2 w

'•5 rt 5t3
c V. o a>

O O^J3
u C (0 ♦<

- do 2

Digitized by

Google

July, 1919.] The Phenomena of Drying Wood.

CO
•-.SJ5

2*^ <^

C to ro

=— c . I I
2 ^^ •- « «

£ ^ C I

*J^t; OB r^
^ {»J3— * »-<

V M

— o

^•3

CM s

:5:

:«

:j?

(>«

;«

«
i

Nf.

::ie

;sf

•d

«>

::^

;s^

::f

iou,:s?

•<*

1 -C

O_|_io

-U

-4

■

•«\

«rt

:5t

•*

-r

cd ^

. ^

• 09^ -c

80 g

"."ill

•"^

K.^.5?

a ea

. Mm

^ . « 4>

•li

III

•Is

lto'3

e.li||

■*j

•^

■^

Digitized by

Google

46 Harry D. Tiemann. [JF. I-

g^phically indicated as in Figs. 6 and 7, in which tension is
shown by distances below the horizontal lines and compression
by distances above. This also shows relatively the lengths which
the strips will assume if the disk be slotted at the condition under
consideration. In the diagrams the combined area above the
horizontal line always equals the area below.

Let us consider what happens in a few cases illustrated in
Figs. 6 and 7.

If a disk be cut and slotted in Case A, the outer prongs will
at once bend out on the saw, although no casehardening has yet
occurred. If then dried slowly the prongs will become parallel
again and of the same length.

In the Case B the outer prong will have a slight tendency to
bend in on the saw, but if the disk be pven a single cut through
the centre the two prongs will bend outwardly on the saw. When
subsequently dried, however, in both cases the prongs will bend
inward. In Case F the same is true to a greater degree. In
Case G, however, the prongs cut anywhere after the third strip
will at once bind on the saw and will still further bind when
finally dried. In Case H, if slotted up at any point, the outer
prongs will at once bind on the saw, and remain so. The inner
prongs 5 to 8, however, will remain straight.

If Case A be steamed at a low temperature or placed in cool,
damp air, the outer portion will swell and offer a compression
effort which will have the effect at first of increasing the tension
on the inner layers, which is a bad effect as it tends to develop
internal checking or cause external checks to run in deeper.
Successive stages are shown in Cases B, C and D. Since the
outer layer is not softened at the cool temperature, it will not
intercrush (or crunch) under compression, and therefore no
advantage is gained, since the same tendency to caseharden
is again set up when it is dried again. If it be steamed,
however, at a sufficiently high temperature to render it plastic,
the outer layer will intercrush slightly as shown in Case E,
and when further drying of the stick is resumed, it will not offer
so great a resistance as it would formerly, as in Case H. Case-
hardening has thus been slightly reduced.

The most salubrious effect of steaming, however, is obtained
after the Case F has been reached, and this reaches its maximum
in the Case H. The effect of high temperature steaming is here

Digitized by

Google

July, 1919.] The Phenomena of Drying Wood.

Fig. 6.
1 2 3 4 5 6

Dr) log Just started. Nos. 1 and 9
have dried some, all the rest

Case A. Strips z, 3. 3, 4 have a
dried some. Strips 5. 6. 7, 8
are still wet.

•• BeRinniiig to casehardeii.

Case F. Reversal ul stresses be-
winning. No. x has case-
hardened. All liave dried
some.

Case G. Further pruifress in case-
hardening. Nos. X, a, 3 have
casejiardened. All have
shrunken.

Case H. Completely dry. The
stresses completely reversed.
Permanently casehardened.

Diagram showing stresses in wood while drying.

Digitized by

Google

Harry D. Tiemann.

Fig. 7.
1 2 3 4 5 6 7s!

[J.F.I.

Cafe I. I mmedlate effect of steam-

Case J. Reversed caseharden-
iag, final result of I when
completely dried.

Ca.se B. E ffect of reabsorption of
strip I cold.

Case C. Nos. i and 2 realisorbed
cold.

Case D. Nos. i. 2. 3 reabsorbed
cold.

Case E. Steamed at high tem-
perature. Compare with B.

Diagram showing stresses in wood while drying.
(Continued from Figure 6.)

Digitized by

Google

July, 1919] The Phenomena of Drying Wood. 49

to completely eliminate the compression stress in the layers
affected, as is illustrated in the single Case I. The ultimate result,
however, provided the effect has not penetrated to all layers under
compression stresses, will inevitably be a reversal of caseharden-
ing, shown in Case J. In this case, if the disk be slotted between
2 and 3, the outer prong will turn out slightly on the saw in
Case I, and much more so in Case J. On the other hand, the
next prong, consisting of strips Nos. 3 and 4, will still turn

Fig. 8.

Discs cut from casehardened maple and oak boards. The alternate ones on the left show the
condition of the boards when first dried; those on the right show reversal of stresses brought
about by steaming the same boards at a slight pressure.

inward, the same as in Case H. If sawed in the middle, however,
there is much less cupping in J than in H ; in fact, it might easily
be that the stresses are balanced so there would l^e no cupping at
all of the half-disk.

If the effect of the steaming be sufficient to penetrate all the
layers under compression, all stress may be removed thereby.

While the cases chosen for illustration are largely empirical,
and actual conditions will vary therefrom not only in relative
intensities but in distribution, it seems probable that the maximum
total stresses are very apt to occur in the first stages of drying
as in Case A. The tension inside the block is at no time as

Digitized by

Google

50 Harry D. Tiemann. [J. FI-

intense as on the surface. It may be that honey-combing starts
initially with a small surface crack, which then follows inwardly
as the wave of tension moves to the centre, somewhat in the
manner that a crack in a pane of glass will follow the progress
of a comparatively slight stress, much less than that whidi would
be necessary to initiate the crack in the unbroken piece. If this
is the case, cold reabsorption or steaming at a low temperature,
before true casehardening has taken place to a considerable
extent, is of no advantage but positively detrimental, as such
treatment is here shown to intensify the tension in the adjacent
layers progressively. High temperature steaming, on the other
hand (Case E), may be beneficial in relieving the ultimate case-
hardening (external compression effect) at the stage indicated in
Case A, and it is certainly beneficial after decided casehardening
has taken place at Cases F and H.

For aeroplanes, unequal moisture distribution, which means
temporary stresses, is undesirable for any purpose. Permanent
casehardening, such as illustrated in Case H, is not of itself very
serious for wingbeams and small parts provided it is not severe;
it may, however, presage an improper drying treatment which
would be ground for rejection of the material. For propellers,
however, any appreciable casehardening is detrimental as the
internal residual stresses may cause changes to take place in the
shape of the finished parts. Moreover, these stresses may change
with time, which may introduce unknown stresses in the blades
or tend to shear the glue joints. Or they may even cause checking
or internal cracking to take place at some future time.

Shock-proof Tungsten Lamp. Anon. (Scientific American,
vol. cxx, No. 25, p. 649, June 21, 1919.) — Despite the many improve-
ments introduced in the manufacture of tungsten lamps, they have
remained delicate until the present. There was a time, of course,
when tungsten lamps had to be handled with extreme care to avoid
jarring and shattering the delicate filament ; but in more recent times
the tungsten lamps have come to be fairly rugged and available for
almost all purposes save in mills, printing plants, and other places
subject to intense pounding or shocks. It has remained for one of
our leading electric lamp manufacturers to introduce a new type
of tungsten lamp which incorporates a shock-absorbing feature.
The filament mounting, instead of forming an integral part of the
glass stem as is usually the case, is spring-supported. This feature
makes this lamp serviceable and preferable under almost all con-
ditions where carbon lamps have been used heretofore.

Digitized by

Google

INDUSTRIAL LIGHTING.*

C. E. CLEWELL.

Aasistant Profesaor of Electrical Engineerins, University of Pennsylvania.

If every working man in the industries of this country lost
one minute per eight-hour day, each day, due to inadequate work-
ing facilities, the economic loss to the country, based on certain
statistics, might approximately be set down as equal to $10,000,000
per annum. Similarly, a loss of one hour per day by the total
employees in all industries would mean roughly a loss well on
toward a half billion dollars per annum. These figures are based
on the estimated wages in this country per annum as reduced to the
total wages per minute or per hour, these factors then being
employed as a basis for the determination of the losses just
mentioned.

Reference will be made later to losses due to poor light and,
conversely, to gains made possible by highly adequate light, and
when the loss of a minute or an hour per day due to poor light is
mentioned, while it may seem trivial in itself, its importance to
the industrial economy of the country will be more evident from
the foregoing general figures, while its relatively large magnitude
when compared to the costs of the best lighting will appear
subsequently.

DBYELOPM EHTS IH GAS AND ELECTRIC LIGHTING CONTRASTED.

Those who have followed the developments in electric and
gas lighting during the past years have probably been impressed
by the apparent rivalry between the manufacturers of gas and
electric lamps and appliances. This rivalry may, it is true,
be only apparent, but it is interesting as throwing into relief
some of the possible influences back of the rapid developments in
these two fields. Gas lighting, as the older of the two, was
employed in about the same way in the form of the old fish-tail
burnefs for a number of years with little or no attention to
reflectors or the scientific distribution of the light. Later, the

* Presented at a joint meeting of the Section of Physics and Chemistry
and the Philadelphia Section, Illuminating Engineering Society, held Thurs-
day, February 6, 1919.

Digitized by

Google

52 C. E. Clewell. [J- F- 1-

electric lamp appeared and the many developments in electric
lamp efficiency and in the effective use of the light from such
sources, has been paralleled by similar developments in gas lamps
and in auxiliaries for the highly efficient utilization of the light
from these sources.

In somewhat the same manner the developments in the means
for securing light in factory buildings has witnessed a contrast
between natural and artificial illumination. There may or may
not have been an actual rivalry between building constructors,
on the one hand, in the design of windows and monitors for admit-
ting daylight, and those who have been responsible for effective
artificial lighting on the other hand, but the past ten to fifteen
years have witnessed marked advances in both of these fields. Not
only has there been an awakening to the needs of the case but
new methods and new types of artificial lighting equipment have
been applied to industrial buildings in recent years and along with
them has come a higher appreciation for buildings so designed as
to admit plenty of daylight and in such directions as to reach the
working surfaces effectively. In what follows, it is the intention
to dwell to some extent on both of these phases of industrial light-
ing, partly by way of pointing to individual characteristics of the
illumination from both natural and artificial sources, and to
some extent in contrasting the two.

SOME CAUSES FOR POOR LIGHTING IN EARLIER PRACTICE.

It might seem at a first glance that the importance of the best
form of illumination for industrial processes is so fundamental
and obvious that there would be little or no need to emphasize
the relations of good lighting to effective and accurate workman-
ship. The widespread neglect of such facilities indicates, how-
ever, that lighting is one of those things in the factory equipment
which can readily be overlooked and concerning which there is
still much ignorance on the part of industrial managers and shop
owners. These conditions make it necessary to dwell repeatedly
upon such things as the value of good light to production, and
also upon the physical means now available for the accomplish-
ment of successful illumination at the working surfaces in the
industries.

Going back fifteen to twenty years, the inadequate illumina-
tion in many older industries may easily have been the result not

■\

Digitized by

Google

July, 1919.I Industrial Lighting. 53

so much of neglect, as of an inability to secure suitable lamps.
The older arc lamps, representative of the larger sizes, and the
carbon filament lamps, of the smaller sizes, each had their own
limitations for the attainment of success in factory lighting.
Large lamps were not adapted to low ceilings and the apparent
difficulties in the v»'ay of providing general and uniform illumina-
tion over the entire floor areas where high ceilings existed, either
with arc lamps or with groups of small carbon filament lamps,
often made localized lighting the logical result in earlier practice.
Intermediate ceilings, falling between low and high clearances,
constituted an unusually large proportion of some factory areas,
and such locations, in earlier practice, sometimes presented greater
difficulties from the viewpoint of general illumination, than either
the low or the high spaces.

The successful use of tungsten and of mercury vapor lamps
for factory lighting purposes marked a new era in this field of
artificial illumination and solved many problems which previously
had been difficult to handle with the very limited lamp sizes in the
arc and the carbon filament types. In fact, the very obvious
advantages of a lamp of medium size, whether tungsten or mer-
cury vapor, are so great in the successful illumination of many
factory spaces, that it is an open question whether the recent
development of nitrogen-filled lamps with very high efficiencies
in the large lamp sizes is an advance equal to the appearance
some fifteen years ago of the older tungsten lamps in medium
sizes, at least so far, as the industrial lighting field is concerned.
In other words, it may be found desirable to illuminate many fac-
tory interiors with less efficient tungsten lamps of the intermediate
sizes so as to secure better distribution of the light through the
larger number of units thus required than to adopt the larger
lamp sizes merely to obtain a unit with a higher candle-power per
watt rating.

REASONS FOR DEYELOPMEKTS IK FACTORY LIGHTING PRACTICE.

In spite of the widespread neglect of the ideas of good lighting
in many industries, there has been a notable development in the
way of better lighting among the plants of the more progressive
class during the immediate past. This development may be
ascribed to the newer types of lamps and to more carefully
designed reflectors, with the possibilities for the highly effective

Digitized by

Google

54 C. E. Clewell. (J- F- 1-

lighting results they have made available, but other factors have
doubtless contributed to this development. One of these perhaps
has been the ideas back of scientific management and the higher
appreciation which these ideas have emphasized for a favorable
working environment for employees. The advantages of good
working facilities, of which lighting is a type, have come to be
looked upon in recent years as tangible and very real factors in the
successful management of American industries, and additional
attention has been directed toward this phase of the subject by
the stress of the recent war emergency, which will be referred to
again later on.

Another influence which has undoubtedly been back of these
developments in factory lighting is the keen interest which has
been taken in the subject by lamp and reflector manufacturers.
Aside from any commercial considerations, this active and pains-
taking work by the manufacturers has been such as to merit the
approval of all of us who view the problem from just as interested
although a less commercial point of view. The need for con-
tinuously keeping these high ideals in mind on the part of the
lamp and reflector manufacturers is, however, increasingly great
because of the effect upon any industry of the law of supply
and demand. People generally to-day confuse good lighting with
extremes in glare and brilliancy from high candle-power lamps.
For reflector and fixture manufacturers to give way to this popu-
lar prejudice favoring brilliancy of lighting units would be a step
backward, and it is to be hoped that light users may in time be
educated up to that point where they will appreciate good illiunina-
tion and the freedom from glare in such a measure as to supply the
necessary commercial demand for equipment which meets these
primary requirements in good lighting practice. It is hardly
necessary to add that the industrial field is one of the important
cases where these comments apply very generally.

Finally, as a fourth cause for the increasing attention to better
lighting in recent years, there may be mentioned the slowly
growing emphasis which is being placed upon the subject by state
labor departments through codes and other legislative enactments
covering industrial lighting. These state regulations, although
drafted primarily with the view of safeguarding employees
through better lighting, and hence not directing attention to any
extent to the economic advantages of good light, except perhaps

Digitized by

Google

^^9] Industrial Lighting. 55

indirectly, have undoubtedly become quite a potential factor in
this field. Some of the developments in state codes will be
referred to later.

RULE OF THUMB VERSUS EXPERT METHODS.

To the popular mind, the duties of the industrial lighting engi-
neer probably consist merely in the choice of lamps and in hanging
these lamps at certain locations. In fact, the actual conduct of
industrial lighting design, or planning, as it might more properly
be termed, by many architects and others, depends to such an
extent upon rule of thumb methods, that such a conclusion may be
valid when referred to such methods. The design of a truly
successful factory lighting system, however, often presents pecul-
iarities and special problems which merit individual attention not
only to given sections of the plant from the standpoint of the
kinds of work conducted, but sometimes to the particular needs
of individual workmen. Hence, it is apparent that the whole
subject can either be looked upon, on the one hand, as one sus-
ceptible to solutions by rule of thumb methods, or, on the other
hand, as one in which highly specialized talent can well be utilized
by the plant management.

To my own mind, the latter method is the best if not the only
safe course to follow. Eyesight is too valuable an asset to the
millions of wage earners of this country, and also to the economic
interests of industry, to neglect the light under which vision must
function in seeing such an infinitely wide variety of industrial op-
erations, where the personal element combines, under both physio-
logical and psychological influences, to still further complicate the
problem. Therefore, merely from the standpoint of providing illu-
mination which is correct both in quality and quantity, expert
assistance is warranted in the making of such plans. Moreover,
there is a wider aspect of the matter, and to give a general idea
of the variety of additional problems which the industrial illu-
minating engineer may be called upon to handle, it may be in place
to enumerate very briefly several items which have constituted a
part of his duties under actual working conditions.

ITEMS CLOSELY ALLIED TO INDUSTRIAL LIGHTING.

These include such things as the study of distribution circuits
and transformer capacities for the supply of constant voltage to
the factory lamps, the study of the proportion of motor load to
lighting load on given circuits, in its relation to voltage variations

Digitized by

Google

56 C E. Clewell. I J- F. I

on the lighting part of such combined loads, and the factors in-
volved in the possible subsequent recommendation that such com-
bined loads on a given circuit be separated. Again, in one factory
I recall steps that were taken to establish the minimum voltages
to apply to given rated lamps for the maintenance of approxi-
mately white light. Other important items have been the estab-
lishment of proper lamp arrangements and suitable intensities for
each class of work and for each location, such as the office, the
drafting room, the foundry and the machine shop. Maintenance
work must be standardized, -since no industrial lighting system
can be expected to keep up to its original excellence unless lamps
and reflectors are cleaned, and burned out lamps are renewed
regularly and promptly.

Many other problems may present themselves, such as the
prevention or, at least, the reduction of theft of lamps in the
large factory; campaigns among the superintendents and the
employees looking towards the intelligent economy of light; the
prevention of polarity reversal on direct current circuits, where
such a reversal may cause instant injury to given types of lamps ;
the large question of voltage drop in the distributing circuits,
which may sometimes include the factor of mutual inductance
where lamps are supplied from two phase alternating current
power mains. Then there is the important point of the most
economical method for producing a given quantity of illumination
at the working surfaces, which includes such factors as light walls
and ceilings ; also the selection of those types of reflectors, whether
glass or metal, most suitable for factory conditions, and at the
same time capable of increasing the proportion of the total light
from the lamps which reaches the working surfaces; the study of
the effects of good light upon rates of production and upon accu-
racy of workmanship; the methods of wiring best suited to the
various types of factory building construction; the best ways to
provide light for stairways and passageways and the relations
of such light to accident prevention; the very special study of
particular cases and operations where unusual requirements are
imposed upon vision ; the relative advantages of clear and of trans-
lucent glass for factory windows from the illumination stand-
point; color effects upon various kinds of material, important in
textile establishments and sometimes in such special cases as the
assortment of metals like copper, brass and iron with their charac-
teristic differences in color.

Digitized by

Google

July, 1919.] Industrial Lighting. 57

RBSPOHSIBILITT OF THB SHOP ELECTRICAL DBPARTMBHT.

Problems of peculiar interests, and sometimes correspondingly
difficult, arise from time to time in such work, and among these
is that of the proper illumination of the instruments on the switch-
boards of the shop power-house, or the faces of time-clocks located
overhead in the aisles of some factories, the illumination of boiler-
room gauges, and of coal bunkers, and that fundamental problem
of providing enough of a side component in the resulting illu-
mination properly to light vertical or side surfaces of the work.

It is readily recognized that many of the foregoing items which
may confront the industrial lighting engineer have received suffi-
cient attention during the past few years to have become in a way
standardized. Furthermore, some of the things mentioned may,
in certain cases, fall under the jurisdiction of other departments
of the plant. The list is given, however, to show that industrial
lighting constitutes a problem of fairly broad possibilities, and
that it touches a variety of the items which go to make up the
shop equipment. Perhaps the close alliance of shop lighting with
so many divisions of the factory equipment may be one of the
reasons why it is neglected or overlooked, through the assignment
of the lighting problem to the care of a factory foreman or super-
intendent in charge of the electrical department or possibly of
the power-house and distributing circuits as well as the motors
and general power conditions, with so many interests that there
is little time available for specialized study of the lighting con-
ditions and their effect upon vision and upon production. How-
ever, there is this compensation even where such conditions exist,
that the shop man directly concerned with the supervision of the
lighting, although often entirely incapable at the outset, through
ignorance of the principles involved, of successfully handling the
problem, will often be found most receptive when suggestions are
made and often develops an aptitude for the work which enables
him to handle it very eflfectively.

THB PERSONAL EQUATION AMONG EMPLOYEES.

The matter of supplying light for the employees of an indus-
try is thus complicated by the infinite variety of operations and
the kinds of things pertaining to the work handled in the various
classes of establishments, which make it utterly impossible to
assign rules, for the simple reason that while they may perhaps
Vol. 188, No. 1123— 5

Digitized by

Google

58 C. E. Clewell. [JFI-

be adaptable to one kind of work, they may at the same time be
entirely inadequate for another. Moreover, the illumination of a
piece of work is not only a matter of furnishing so and so many
units of illumination intensity upon that work, but its effect in
rendering the work visible will be governed very largely by
physiological and psychological characteristics of the workman
himself. It is not surprising, therefore, to find a person dissatis-
fied with an ideal lighting system, not because of any difficulties
in seeing the objects illuminated, but because the lamps " are
too high," or ** the quality of the light is too cold," or " the bowls
of the lighting fixture are too dim./'

On the very face of it, therefore, where light must be fur-
nished to many employees in large office or shop sections, it is
almost fundamental to the successful handling of the problem
first, to know what is the right and proper method to adopt and
then to adhere to this in spite of criticism on the part of employees
until such time as the system has been given a fair trial, and
individual rather than collective comments can be sifted out.
When this time arrives, say after a month of trial for the new
system, then individual complaints can well be investigated and,
where necessary, remedied.

In this connection, I have seen large factory sections where
individual lamps were depended upon solely for the light, and
where a new system of general illumination with overhead lamps
was about to be installed, when the foremen and superintendents
foresaw a distinct need for the retention of the local lamps close
to the work. A general complaint in advance of the new installa-
tion was forestalled by the simple expedient of agreeing to remove
all drop lamps at the time the new system went into effect under
the condition that those drop lamps which might be called for
after, say a six weeks' trial of the new system, would be rein-
stalled if found actually necessary. The success of such an expe-
dient can be wtry gratifying to those responsible for the new
system, if the new system is really a superior one, but the designing
engineer should never be so sure of himself as to neglect proper
attention to individual complaints, which are aften entirely
justified by special circumstances. It is a cause for regret that
there is a notable tendency to turn down such complaints after
a new system is installed which the proprietors consider first-class,
and I have run across cases of this kind where such a policy

Digitized by

Google

July, 1919] Industrial Lighting. 59

worked a real hardship upon certain employees, for whose work
the new system did not meet the needs for good vision.

PHYSICAL ASPECTS OF THE PROBLEM.

To these subtle physiological and psychological factors there
must be added the physical part of the problem, which is concerned
with such things as the surroundings of the location to be lighted,
the class of things to be seen, the intensities of illumination to
provide, and the types of lamps and of reflectors to use and their
suitable arrangement. To take all of these factors into account
obviously calls for the assistance of specialists in a number of
fields, and, conversely, thus indicates why those interested in illu-
mination constitute such an exceedingly wide variety of profes-
sions. The personnel of the membership of the Illuminating
Engineering Society is a reflection of this interesting feature, and
the presence in its membership lists of physicians, ophthalmologists
and psychologists, as well as of physicists and engineers, is an
index to the ramifications of the field.

Turning now, however, to some of the effects of surroundings
and of working conditions generally upon the industries as a
whole, we find, first, that light holds an important place in what
may be termed the factors which determine the character of the
shop environment; and second, that light, as one of the factors,
is closely related to the employee through its effect on his ability
to see clearly, and thus, in turn, to the production rate, to the
amount of defective workmanship, and to the likelihood of
accidents.

INDUSTRIAL LIOHTIHO AND THEjWAR INDUSTRIES.

This close relationship between good and bad light, as the case
may be, and the welfare of the employee, together with what has
seemed for years to be a more or less close relationship between
good light and normally rapid production, between good light
and better workmanship, and between good light and a low acci-
dent rate, may be taken as an indication of why the question of
highly adequate light for the industries was looked upon during
the recent war as an item of fundamental importance to war work.
In fact, one of the departments of the War Industries Board,
known as the Employment Management Division, committed itself
during the past year, prior to the signing of the armistice, to the
preparation of instruction courses, for employment managei^s

Digitized by

Google —

6o C. E. Clewell. [J- F- 1-

throughout the country, which contained plans for advancing
the ideas of such men, by intensive instruction, in the relations of
just such factors to the employee, to production and to the
accident rate.

This is a significant point. To aid the industries under the
pressure of a war emergency, natural and artificial lighting were
considered an important part of an intensive war program. The
campaign to gather information for these purposes last year forms
an interesting commentary upon the necessities and urgency of
work under the pressure of war needs. It was my own privilege
to gather a large amount of data for the Employment Manage-
ment Division of the War Industries Board, at its suggestion and
by its authority, on natural and artificial lighting last year before
the close of the war, and the cessation of hostilities has led this
Division to place at my disposal practically all of the files of data
and other information thus accumulated, so that I am privileged
in a part of what follows to comment on certain interesting points
and on some conclusions based on the information gathered during
the past year as a part of the war program.^

RBLATXOirS OF GOOD LIGHT TO PRODUCTXOir.

The exact relations of good light to industrial management
are important for several reasons. First, and perhaps foremost,
is the necessity of convincing the factory manager that the expen-
diture for a highly adequate system is warranted by the eflfects it
is likely to have upon the management of his employees; and
second, in the assurance which such relations give to the industrial
lighting engineer or salesman that his eflforts to raise the standards
of factory lighting are warranted by the results. These relations
of good light to management have been expressed in a variety
of ways on a basis of the more or less obvious effects it is likely
to have on increased production for the same labor cost in a plant,
in the greater accuracy of the workmanship in the well-lighted
shop, in the reduced accident hazard, in the avoidance or the
minimizing of eye strain, and the healthy reaction upon the
working force due to the more cheerful surroundings and the
more comfortable conditions afforded by the light versus the
gloomy interior. Adequate general illumination also removes

*Thc Employment Management Division of the War Industries Board
now forms a part of the Federal Board for Vocational Education.

Digitized by

Google

July. 1919.] Industrial Lighting. 61

dark corners, and it is commonly observed that such a shop is likely
to be kept cleaner than companion spaces which are relatively
dark. Greater attention to janitor service promotes neatness on
the part of the employees and thus tends to raise the tone of
the plant.

These advantages of good light are all valuable as showing
its importance to any plant and they have often formed the basis
for decisions to install better lighting in places formerly very
poorly illuminated. However, to say that good light promotes
production and reduces accidents is a qualitative statement. The
average shop manager is receptive to such ideas ; but, in themselves,
such abstract statements are difficult to translate into actual returns
for the expenditure involved and hence lack the definite character-
istics which would so often convince the manager that his judg-
ment concerning the need of a new lighting system is correct.

ANALYSIS OF LIGHTING COSTS.

One of the first steps towards a more definite basis for setting
forth the advantages of good shop lighting was the now well-
known type of analysis suggested by Chas. F. Scott in an editorial
in the Electric Journal in May, 1910, in which he emphasizes a
new viewpoint in the consideration of industrial lighting, by
suggesting that the cost per day for the best lighting system in a
given factory section may conveniently be evaluated to the equiva-
lent wages per day in that same section. At a first glance it does
not appear just what such an evaluation may amount to, but since
Professor Scott's suggestions in 1910, this relationship has com-
monly been found to be on the order of two to six minutes. In
other words, the entire cost for lighting a shop section per day
will usually be found to be the equivalent of the wages in that
section for several minutes of the entire working day.

The foregoing figure has often proved to be most conclusive
in the survey of an old system and one which has been entirely
inadequate, because of the relative ease with which time losses
due to inadequate light may be observed by inspection of the shop
and by inquiries of the foremen and others in charge. Any shop
section, therefore, in which time losses of, say a half an hour per
day, occur because of poor light, should obviously reap quite a
reward by the adoption of a new and improved system at a cost
for operation of one-sixth of the daily loss in wages due to the
old system.

Digitized by

Google

62 C. E. Clewell. [J- F- 1-

BZPBRT OPINIOirS ON THB LIGHTING NEEDS OF THE INDUSTRIES.

This form of analysis, coupled with personal investigations
in the field, have long been used as the basis for the commonly
accepted idea that good lighting aids factory production, and that
the average lighting conditions in the industries could well be
raised to standards considerably in excess of present values. In
fact, during the past year, that is to say, before the close of the
war, a canvass was made among leading illumination experts in
this country ^ to ascertain by how much industrial lighting ought
to have been adjusted or changed from standards existing before
the war in view of the fuel shortage and of the war, with the result
that opinions favored an increase of 50 per cent, in industrial
lighting in spite of an opinion that it ought to be decreased in
every other branch of the lightihg field, such as street, public
building and commercial lighting. The figure of 50 per cent,
increase appears to have been a conservative opinion because of
the opinion of these same experts that without regard to the war
conditions and the recent fuel shortage, industrial lighting stan-
dards could well be increased by 175 per cent. These opinions,
it will be noted, favored marked increases in the quantity of light
used for factory operations.

Now the codes of lighting recently issued by the several states
who have given this matter special attention, contain tables of
the quantities of light as a minimum and as desirable for given
classes of work. These quantities have been based on the objec-
tive feature of safeguarding the workmen. They have not been
based directly on the values desirable from the standpoint of
maximum production at the least labor expense, for the simple
reason that the state departments of labor are primarily concerned
in regulations for the protection of labor, physically speaking.
If a table of quantities of light for various classes of work were
to be prepared on the basis of the most favorable production rates,
there would be a strong tendency materially to increase the values
found in these state lighting codes. In the past the magnitude
of the increases in the quantities of light over and above the
minimum values required by considerations of safety to the eye-
sight of employees and as a safeguard against accidents, has

* Paper on " Lighting Curtailment," by Preston S. Millar, Trans. Illumi-
nating Engineering Society, Vol. xiii, No. 2, p. 126.

Digitized by

Google

July. 1919] Industrial Lighting. 63

largely be'en based on individual experiences in various cases. To
a large extent this condition prevails also at the present time.

RBCElfT TESTS ON LIOHTXITG AND PRODUCTION RATES.

To ascertain the desirable quantities of light to use on a
basis of production rates calls for study of the rates of production
under different quantities of light ranging from lower to higher
values, keeping all other factors in the management of the plant
as nearly unchanged in the given section as possible while the
investigations are under way. Obviously, this is a task of con-
siderable difficulty and data of this nature have been slow to
materialize. Reports * on tests in a number of plants in the
Chicago district show what appears to be an interesting relation
between the production rate and the intensity of illumination
provided at the work^ In one plant, for example, increases in
production of 8 to 27 per cent, in various operations followed
an increase in the intensity of illumination from 4 to 12 foot-
candles, the lower and higher values having been in use for two
consecutive months. These figures tend to verify the close rela-
tionship existing between adequate light and the rate of work,
and the figures just quoted also contain the further interesting
commentary on costs of light in that a general figure is given in
the report that by the expenditure for better lighting of about
5 per cent, of the pay roll in a plant section, a 15 per cent, increase
in production can usually be secured, this conclusion being based
on the above and other tests in the Chicago district.

RELATIONS OF GOOD LIGHT TO ACCIDENTS.

The above relations of good light to production contain the
basis for much help in the education of shop management up to a
higher appreciation of the advantages of such facilities. There is,
however, the other important aspect of light as a factor in indus-
trial accidents. For adequate data on this phase of the subject
we may turn profitably to the Casualty Insurance Companies,
because their interests are intimately connected with accident pre-
vention, and if lighting is a material factor, it would naturally be
one of the items of the shop equipment to engage the attention
of such casualty companies.

From such sources reports from time to time have shown

• A Paper on " Productive Intensities," by Wm. A. Durgin, Trans. Illu-
minating Engineering Society, Vol. xiii, No. 8, p. 421.

Digitized by

Google ^

64 C. E. Clewell. [J- F- 1-

that the industrial accident rate in this country is influenced
to quite an extent by improper or inadequate light. In fact, the
extent of this influence has been expressed as equal to about i8
per cent, at the present time; that is to say, about i8 per cent,
of all industrial accidents are said to be due directly or indirectly
to poor, or what may be termed defective, lighting conditions.*
This may be interpreted as the quivalent of so much labor loss per
annum and estimates place this loss as the equivalent of removing
about 100,000 workmen from American industries for an entire
year each year. The similar estimate for the labor loss due to
accidents from all causes has been set as the equivalent of remov-
ing about 600,000 men for an entire year each year, so that the
loss due to poor light is seen to be about one-sixth of the total.
In 19 10 the per cent, of total industrial accidents chargeable to
poor light, directly or indirectly, was set at about 24 per cent.,
although the investigation of the records of the particular Casualty
Insurance Co., on which the figure was based, resulted in a
figure of about 10 per cent, in 1910 for the accidents due pri-
marily to poor light, whereas the remaining 14 per cent, repre-
sented cases where poor lighting was merely a contributory cause.^
Apparently the figure of about 24 per cent, for 19 10 may be com-
pared roughly with the more recent figure of 18 per cent, for
19 18, on the basis of which the conditions seem to have improved
slightly in the eight-year interval.

HIGH ACCIDENT RATE IN WINTER MONTHS.

An interesting conclusion has been drawn from the well-known
curves of Mr. John Calder, first published in the Transactions
of the American Society of Mechanical Engineers, as showing
the increase in the number of accidents in the industries which
are fatal for that part of the year in which normal day hours from
7 A.M. to 6 P.M. are partially dark. This conclusion® indicates
that the number of accidents in the months of December and
January are usually greater than the number that would be
expected from the curves if the same amount of light (daylight)

*A Paper on "The Relation of Light Curtailment and Accidents," by
R. E. Simpson, Trans. Illuminating Engineering Societ>% Vol. xiii, No. 8, p. 431.

• A Paper on " Illumination and One Year's Accidents," by R. E. Simpson,
Trans. Illuminating Engineering Society, Vol. x, No. 9, p. 870.

• See reference given in footnote 5, p. 869.

Digitized by

Google

July, 1919] Industrial Lighting. 65

existed in winter as in summer. In fact, the increase based on
the given curves has been set at 40 per cent.

To the foregoing figures there might be added many con-
vincing descriptions of specific cases where poor lighting has been
the primary cause of accidents, both fatal and less serious, as
compiled from the experiences of the Casualty Insurance Compan-
ies, and these would tend to confirm the general conclusions just
mentioned concerning the relation between light and industrial
safety. The fact that poor light is a large factor in accident
hazard has probably been covered sufficiently, however, to indicate
why state labor departments have begun to include lighting
regulations among their industrial rules as one of the important
factors in the whole campaign of accident prevention and the
safeguarding of the life and limb of industrial employees.

ENGINEERIITG DETAILS OF NATURAL LIGHTIITG.

The engineering details involved in planning for natural
lighting facilities are fundamentally more difficult than those for
artificial illumination because of the extremely variable nature
of the daylight throughout given days and for the same hour of
the day at different times of the year. Furthermore, many factors,
such as the use of side windows which supply natural light in a
manner not symmetrical to the floor space, and the presence of
nearby structures to impede the light, make it very difficult to
assign definite rules for daylight planning.

The general trend of development in the desgin of modern
factory buildings has been to employ larger and larger proportions
of window space, until extremes have been reached in some cases
and the natural illumination has been made excessive and uncom-
fortable to the employees housed in such structures. Architects
and other factory construction designers tend to work towards
constants such as certain ratios of window area to floor area in
their plans, and this can be made a good basis, provided such
constants are used with due regard to the fundamental points
involved. Without using proper care in the application of such
constants, window planning reduces to little more than a rule of
thumb calculation, and the results may be good or bad, depending
on the nature of the factors which surround the structure.

To illustrate the attitude taken towards the use of such con-
stants it may be in place to mention a very caustic letter which I
received some time ago from a party interested in the problem

Digitized by

Google

C. E. Clewell.

[J.F.I.

of reducing structural daylight plans to a simple formula basis.
I had taken the attitude that due to the large number of factors
involved, set rules were difficult to formulate. This I still feel
to be the case, although the tendency of well-designed factory
buildings to adhere to fairly well-defined ratios of the window
to the floor space may be taken to indicate the possibility of using
such figures for new structures with proper precautions.

Fig. I.

Plan

SOME FACTORS IlfVOLVED VR DAYLIGHT PLANITING.

I shall endeavor in the following paragraphs to show, first,
some of the factors which the plans for interior natural lighting
include, and then to point to the basis which may be taken in the
formulation of simple rules for such work. First, consider the
eflFect of adjacent structures. A window which might admit a
generous supply of daylight is often rendered more or less useless
by the presence of a taller building located only a short distance
away. This is shown in the upper part of Fig. i by the line

Digitized by

Google

July. 1919] Industrial Lighting. 67

passing from the upper part of the structure on the left, through
the top of the window to the floor within. Any point on the
bench surface to the right of the intersection of this line with
the surface receives no direct light from the sky through the left
window. Similarly, no point on the floor to the right of a in the
diagram receives any light directly from the sky through the left
window. This does not mean, of course, that those parts of the
floor to the right of a are in darkness, but the light must come
from reflections from the opposite building face or from reflec-
tions from those parts of the building interior which receive light
directly from the sky, as far as the left window is concerned.
The actual daylighting effect in such a building might be decidedly
different from that in an exactly similar structure where such an
obstruction (that is to say, the building on the extreme left) did
not exist, and it is just such a factor that the constants of ratio
of window to floor area cannot in themselves well include.

XULTIPLB STORT BUILDIHOS.

Similar obstruction effects are of'ten very pronounced in the
lower floors of multiple story buildings. Note in Fig. 2 the fact
that the window to the right in the fourth floor admits light
directly from the sky all the way across the room, whereas the
effect of the taller structure to the left is to curtail to a considerable
extent the effectiveness of the fourth floor window on the left.
Left windows on the first floor are practically useless as far as
any light directly from the sky is concerned. Effects of this kind
are experienced daily in the offices of tall office buildings in con-
gested parts of the city, where artificial light is required contin-
uously throughout many days in spite of the normal window areas
provided.

An inspection of Fig. 2 will show that if the ratio of window
area to floor area is specified from tables of such constants with-
out regard to differences in the effectiveitess of the windows for
the various floors, the actual illumination will vary considerably
for different floors unless some special devices, such as suitable
prisms, are used for the lower floors to re-direct the light over
wider floor areas than is possible with plain window glass. ' Put
in another way, a set rule for the ratio of window area to floor
area, in a case like Fig. 2, might give adequate interior lighting
for the upper floors but it might be very inadequate for the lower
floors.

Digitized by

Google

C. E. Clewell.

[J.F.I.

LIOHT TRANSMITTED THROUGH WIITDOW GLASS.

Fig. 3 indicates the decrease in the per cent, of light trans-
mitted through plain window glass in terms of the light incident
upon the outer surface of the window for various angles of inci-
dence, the definition of angle of incidence as here employed being
expressed by the small auxiliary diagram at the top of the figure.^

Fig. 2.

This diagram illustrate§ the importance of rather low angles of
incidence for plain window glass if the per cent, of transmitted
light is to be large. Where the angles of incidence are high,
as with the lower story windows of tall buildings with other tall
buildings opposite, the amount of transmitted light for plain glass
is reduced, in general, according to this curve, and the necessity

* See " Principles and Design of Interior Illumination," by L. B. Marks.
" Lectures on Illuminating Engineering," Johns Hopkins Press, Vol. ii, p. 663.
S-ee also Metal Worker, Plumber and Steam Fitter, Jan. 4 and 18, and
Feb. I, 1918.

Digitized by

Google

July, 1919.]

Industrial Lighting.

of special types of glass for the re-direction of the light into the
building becomes relatively greater. This curve starts with 10
per cent at zero angle of incidence, meaning that plain window
glass is assumed to absorb about 10 per cent, of the light normally

Fig. 3.

G/09S

Incidence^

/OOr-

fO 20 30 40 S> 60 70 90 90

Angles af Incidence 'Degrees

incident upon its surface. I am indebted to Dr. Peter A. Callan,
of New York City, for a reference to the work of Sir William
Crookes, about 1909, on glass. He mentions what is termed glass
No. 187, made up of fused soda flux 83 per cent., and cerium

Digitized by

Google

yo C E. Clewell. [J- F- 1-

nitrate crystallized 17 per cent., for which the claim is made that
99 per cent, of the light incident to the surface is transmitted/

TTPBS OF FACTORY WINDOW GLASS.

The use of types of glass other than plain glass for factory
windows has received considerable attention. The well-known
tests of Prof. Chas. L. Norton, of the Massachusetts Institute of
Technology, along this line, may be summarized as follows : (a)
That the common rough plate or hammered glass has very little
action as a diffusing medium, giving no perceptible change in
the effective light within the building; {b) that the light in a room
30 or more feet deep may be increased from 3 to 1 5 times its pres-
ent effect by using factory ribbed glass instead of plain glass in
the upper sashes; (c) that of the ribbed glasses, the factory ribbed
with 21 ribs to the inch is distinctly the best, and not, in all proba-
bility, because of the fineness, but because of the greater sharpness
of the corrugations; (d) that ribbed wire glass is about 20 per
cent, less effective than the ordinary factory ribbed glass \ {e) that
prism glass, like the factory ribbed, is more effective in increasing
the light when the light is restricted, as in a narrow alley or light
shaft, than when the window has an open exposure with a wide
sky angle; and (/) that rooms with windows opening upon light
shafts and narrow alleys with very limited sky, where the available
light is now small, may have the light 20 feet back from the
windows increased ten to twenty times by using prisms.®

The Aberthaw Construction Company has derived the follow-
ing conclusions from information they have gathered, namely,
that ( I ) the ribbed glass, prices being equal, is under all conditions
better than the rough or hammered glass, giving more light under
favorable conditions and as much light under all conditions;
(2) the objection due to dirt and dust collection on the rough
surfaces can be obviated; (3) prism glass is really worth while
and will positively increase the amount of light under certain
conditions; and (4) ribbed wire glass is about 20 per cent, less
effective than ordinary factory ribbed glass.

" Philosophical Transactions of the Royal Society, London, Series A,
Vol. ccxiv, pp. I, 25.

" From information submitted by the Aberthaw Construction Company,
for the use of the Employment Management Division of the War Industries
Board, 191 8.

Digitized by

Google

July, 1919- ]

Industrial Lighting.

RBFLECTIOirS FRQH OPPOSITE BUILDING FRONTS.

The effect of reflections from opposite building fronts has
been investigated and the curve in Fig. 4 shows the results for
various reflection constants of the adjacent or opposite building
faces. ^*^ The curve here shown is based on three reflections from

Fig. 4.
I/lumtnat/on in foof Candies - 10 ft from Sround Lere/

^ s s » * » s ^ ' "■;

I JlluminafionDue
'ZDfrectJ/fi)ff)e5ky'

the opposite building front, and indicates the importance to in-
terior lighting in relatively narrow streets faced on each side by-
high buildings of having the fronts of the building light colored.
Factors of the kind just discussed show that various factory
buildings of the same general outlines and with equivalent ratios
of window to floor area may have widely different daylight illu-
mination effects throughout their interior working surfaces.

THE DAYLIGHT FACTOR.

It is of interest at this point to consider the natural illumination
within a factory in comparison with that at a point outside the
building under the open sky. These differences have been com-
mented upon from time to time by various writers, but their
significance to the interior lighting problem, particularly in older

" See reference quoted in footnote 7, p. 665.
C O. Basquin.

Based on original tests of

Digitized by

Google

C. E. Clewell.

[J.F.I.

structures, may readily be overlooked. The ratio of the illu-
mination intensity at a point within a factory to the intensity at
the same point, if it were exposed to the open sky, may be termed
a measure of the daylight efficiency of a building for the given
point, and it is sometimes called the " daylight factor " for the
given point." A simple suggested method for determining the

Fig. 5.

VfindO¥f

y^ Floor

• in* Floor

Make a Slmulfaneous
Afeas urmmmnf of theJDc/'
liohl flluminafhn oof
Under th9 Open Sky

Measure the Dq/llah t Tlhrni-
nation of the Shfen Pointy

Eleration

daylight factor for a given point within a building is shown in
Fig. 5. Average values of the daylight factor in a report issued
by the British Government range from 0.25 to 2.3 per cent, for
given cases investigated, of course with values above and below
these averages, and the lowest values referring to day lighting
with side windows only.

The extreme variations of exterior natural illumination inten-
sities are suggested by Fig. 6,^^ which shows the conditions for
June, September and December in one geographical location. It is
now possible to work out for any given daylight factor correspond-
ing to one or more points within a factory, what the intensities of

" Suggested by A. P. Trotter and subsequently developed by P. F. Wal-
dram. See the First Report of the Departmental Committee on Lighting in
Factories and Workshops, London, 19 15, p. 38.

"See footnote 11, p. 64, of the Report referred to. Some daylight meas-
urements in this country may be found in Trans. L E. S., Vol. xi, No. 3.

Digitized by

Google

July, igig.]

Industrial Lighting.
Fig. 6.

4&00

'4000

JSbe

Typtcalflune

nnu

JOOO

:>»

lyptcc

Day

yfem6er

^ fSoo

JOOO

Typ

ica/Decei

■nber

Joo

r €

} II

? /

-f

S 6

-J.M.-

P.M.

Fig. 7.

IVl

ZA.M. Noon 3RM, BA.M, Noon 3PM, SAM. Noon 3PM.

Vol. i88. No. ii2j— 6

Digitized by

Google

C. E. Clewell.

IJ.F.r.

natural lighting will probably be at different hours of the day and
for different days of the year. This liiay be done in conjunction
with a set of curves similar to those in Fig. 6 corresponding to
the geographical location in question. Fig. 7 indicates the intensi-
ties for 8 A.M., at noon and at 3 p.m. for what may be called typical
December, September and June days and shows that for the as-
sumed daylight factor the intensities fall below 3.5 foot-candles
all day on typical December days and for a part of the day on
tjrpical September days. Values worked out on this basis could
readily be used to show roughly the number of hours per day for
various months when the daylight should be supplemented by arti-
ficial light.

XODERir FACTORY BUILDINO CONSTRnCTIOir.

The structural developments in factory building design have
been quite marked in recent years. Fig. 8 indicates, for example.

Fig. 8.

ryM9h

the section of a patented Pond truss of the David Lupton's Sons
Company, where the problem of ventilation has been combined
with that of the natural illumination. The dotted lines in this
figure show the ventilation air currents, while the under concrete
surfaces of the V-shaped structure furnish reflecting backgrounds
for re-directing the daylight, admitted through the upper win-
dows, to the floor beneath, and thus tend to distribute the daylight
uniformly on the working surfaces throughout the shop. Fig. 9
indicates one of these buildings in the process of construction,
while Fig. 10 shows the interior of such a structure after com-
pletion. Some ideaiof the uniformity of the interior illumination
miay be gained from this view.

The expense of steel sash for factory windows is roughly
equal to the equivalent wall area under certain assumptions as
to the thickness of the walls and the types of construction in-

Digitized by

Google

July, iQig] Industrial Lighting. 75

Fig. 9.

Fig. io.

Digitized by

Google

76 C E. Clewell. [JF-L

volved. As the area of window space increases for given floor
space, however, the heating facilities for the maintenance of a
given temperature during winter months also increases and tends
to offset the advantages which might be claimed for indefinitely
increasing the sash area. Thus it has been found in one given
case that the use of side wall windows instead of continuous sash,
with a decrease in glass surface and a corresponding increase in
solid wall area, would result in a less costly heating plant, the

Fig. II.

heating plant with continuous sash and the increased glass area
for this particular case costing about lo per cent, more than where
side wall windows with a decreased glass area are employed.
These figures apply, of course, to one given case only. (Reported
byMr. E. U. Smith.)

The regulation of windows and continuous sash for venti-
lation purposes is of course important, and in Fig. ii the ability
to open the long lines of so-called Lupton continuous sash is
demonstrated, such motion being possible either by hand or by
power operated devices.

The possibilities of highly adequate daylight facilities through

Digitized by

Google

July, 1919.] Industrial Lighting. 77

properly designed buildings are probably apparent from the fore-
going notes. Specific rules would be desirable for window plan-
ning in factory buildings, but the above shows that the problem
is complicated by factors of design. Simple rules will doubtless
materialize, and in fact it would be possible here to append ratios
of window area to floor area for a great variety of factory struc-
tures, but they may readily be obtained by anyone interested in
the problem from the sash manufacturers and, moreover, it is
well to remember that such figures, in themselves, may at times
be misleading and should only be applied to a proposed new build-
ing if they include in their application such important considera-*
tions as typified by (a) adequate daylight in all parts of the
building during normal daylight hours ; that is to say, the suitable
distribution of the light; (&) the avoidance of extremes in glare,
and (c) proper limits, without prejudice, of course, to the ade-
quacy of the natural illumination, governed by heat losses where
window areas are made too large and where the heating costs
increase correspondingly.

EITGIirEBRIirG DETAILS OF ARTIFICIAL LIGHTIITG.

The comparative simplicity of the design of artificial lighting
systems in contrast to those for natural lighting has already been
referred to as being due partly to the possibility of a more sym-
metrical arrangement of lamps, when mounted overhead, and
when referred to the working surfaces which are distributed
through the floor space, than where side windows are depended
upon as the sole source of the natural light. This is made clear
by a comparison of Figs. 12 and 13. In Fig. 12 it will be noted
that there is a lack of symmetry in the distribution of the daylight
on the floor area, the intensities being greater near the side wall
windows and fairly deep shadows being cast on the floor near the
centre of the room. Of course, it is apparent that if roof lighting
is employed, the distribution of daylight can be made much more
uniform than in Fig. 12, but roof lighting is limited to single
story buildings or to the top floors of multiple story structures.
Fig. 13 shows a factory space with the artificial lighting system
in use at night. It will be noted in Fig. 13 that the distribution
of light over the entire floor and working areas is unusually good,
due to the symmetrical arrangement of the mercury vapor lamps
over the ceiling area. This view also indicates in an exceptional
manner the great advantage in the use of medium-sized lamps for

Digitized by

Google

78 C E. Clevvell. (J- F.I.

Fig. 12.

Fig. 13.

Digitized by

Google

July, 1919] Industrial Lighting. 79

Fig. 14.

Fig. 15.

Digitized by

Google

8o C. E. Clewell. [J.F.L

factory sp^^ces with intermediate ceiling heights such as here
shown.

TYPES OF LAMPS.

The principal types of electric lamps now used for factory
lighting are the Mazda and the mercury vapor types. Arc lamps,
although used to some extent in earlier practice, have given way
in many cases for interior industrial purposes to the other types.
A typical Mazda lamp installation is shown in Fig. 14, while
Fig. 15 shows a section of the Gould and Eberhardt works at
Irvington, N. J., equipped with mercury vapor lamps. In addition
to the lamps down the central part of this aisle, it will be noted
that the same type of lamp is employed under crane runways on
either side of the aisle for the illumination of benches and nearby
floor space. Either system, that is to say, with Mazda or with
mercury vapor lamps, can be planned so as to give excellent
results, and quite a number of industries make use of both systems,
employing the mercury vapor lamps in those parts of the shop
where the particular quality of light from such sources is con-
sidered as meeting the special needs of the work, and the Mazda
lamps in other departments.

REFLECTORS FOR MAZDA LAMPS.

With the Mazda lamps the need of reflectors is particularly
great on account of the character of the distribution of the light
from the bare lamp, and also because of the great brilliancy of
the lamp filament. In fact, the design of any industrial lighting
system should be based upon a careful study of the reflectors to
be used with such lamps, if the system is to be effective and
highly efficient in the utilization of the available light. Fortu-
nately, a good deal of attention has been given to reflector design
and the types now on the market are sufficient to meet ordinary
needs provided they are selected intelligently. Standards, which
take into account the factors which the reflector should accomplish
and the proper points in the design of the reflector to meet these
factors, have been developed, and it is planned to market such a
standard line of lamp auxiliaries under the trade designation of
the R L M standard.

An interesting development in recent reflector design has been
worked out in the so-called " Reflecto-Cap " type, in which a small
cap is placed beneath the lower part of the lamp bulb, thus protect-
ing the eyes of employees from the brilliancy of the filament itself.

Digitized by

Google

July, 1919.] Industrial Lighting. 81

The inner surface of this close-fitting cap is finished so as to be
a good reflector and thus re-directs a fair proportion of the light
that would ordinarily go downward to the under side of a large
metal reflector placed above the lamp. This scheme approximates
an increase in the area of the light source and produces a less
harsh effect than that of a system in which the bare filament of
the lamp is visible. A system of lighting making use of this
Reflecto-Cap unit is shown in Fig. 16, and the excellent quality

Fig. 16.

and distribution of the light is evidenced, to some extent, by the
freedom of shadows on the floor space, in spite of the numerous
machines in this shop.

THE OVERHEAD VERSUS THE LOCALIZED SYSTEMS OF LIGHTIITG.

In Fig. 17 a good example is shown of what may be termed the
overhead or the general system of factory illumination, these terms
being used to distinguish it from the older, although frequently
used system of local lamps placed close to each machine or directly
above and close to each bench surface. In older practice, it was
often found that some general illumination from overhead lamps
was desirable in addition to that of lamps close to individual

Digitized by

Google

82 C. E. Clewell. [JF I.

machines. The function of the general illumination in such cases
was to furnish some light to the spaces between machines and
in the aisles, the latter spaces ordinarily being provided with a
less intensity than the points of work directly under the local
lamps. The possibilities of using Mazda and mercury vapor lamps
overhead and in such density of numbers as to furnish highly
adequate illumination over the entire floor area, has led to quite
a general adoption of this method of lighting by many pro-
gressive plants.

Fig. 17.

The illumination of the entire floor space of a factory section
to an intensity adequate for accurate workmanship might seem at
first to l3e an uneconomical procedure inasmuch as a part only
of the floor space is usually so used at any one time. However, the
following advantages commend it as worth while : (a) With every
part of the floor space equally well lighted, work may be con-
ducted at any point of the floor without regard to the location
of the lamps. This makes it possible to arrange the work, the
benches, assembly and other operations, in such a way as to
facilitate the sequence of operations and so as to accommodate
the best scheme of routing materials, without any regard to the

Digitized by

Google

July, 1919] Industrial Lighting. 83

lamps. If it becomes desirable from the standpoint of manufac-
ture to move a bench or to rearrange the location of some of the
machinery, local lighting nearly always requires some readjust-
ments of the lamps and the wiring, which is not only expensive
but a decided inconvenience. (&) The prevalence of shop acci-
dents in aisles and spaces adjacent to machines rather than at the
machines themselves, indicates the importance of adequate light
not only at the machinery but also in the adjoining spaces. The
general overhead system obviously takes care of this point, (c)
Moreover, the idea that machine tools should have a local lamp
or lamps close to the working position of the operator is often
erroneous. Where the general lighting is made adequate in inten-
sity and where the side component of the illumination is sufficient
from overhead lamps to illuminate successfully the sides of the
work in such machines, the problem may readily be solved, in
many cases by the overhead scheme^ without resorting to individ-
ual or local lamps.

IITTBHSITIES OF ARTIFICIAL LIGHTING.

Three principal points stand out in the design of any factory
lighting system, namely, the quantity of the illumination to use
for given classes of work, the proper distribution of the light,
and the az'oidance of glare. These points, without regard to other
items which must often also be taken into account, are funda-
mental to the success of the average system. Although the quantity
of light is often popularly looked upon as the item of, greatest
importance, at the present time the avoidance of glare may be
taken as probably more vital to the interests of eyesight than
either of the other items just mentioned. This statement is
based upon the unusual neglect of factory .owners to employ
shielding devices, such as reflectors or shades, with the brilliant
Mazda lamps which are now so commonly used. It may be noted,
however, that while the use of reflectors is practically fundamental
to the avoidance of glare with Mazda lamps, the use of reflectors
also bears very closely upon the other two factors of quantity
and of distribution of light.

It is well to note that a comparison between natural and
artificial lighting indicates that the ordinary intensities of natural
light are far in excess of those which can economically be looked
for, or which are even necessary with artificial lighting. Thfe
eye possesses a marked degree of flexibility in the illumination

Digitized by

Google

84 C E. Clewell. [JF.L

intensities with which vision is possible and comfortable. A
simple test of this is to read a newspaper in the elevated or sub-
way surface cars just before entering the subway from daylight
conditions and to note that little effort is required to continue
reading comfortably under the electric car lamps, although the
intensity of the artificial light may be very small in comparison
with the intensity of the previous daylight. Another impression
may be gained of these large differences by noting that interior
intensities of 50 or more foot-candles are common near windows
by day, whereas at night, reading may be done comfortably with
artificial lighting intensities of, say, two or three foot-candles;
that is to say, only 5 per cent, of the foregoing daylight value.
This means that due to the peculiar adaptability of the eye to
lower intensities of artificial illumination at night, it is not neces-
sary to provide nearly as high intensities with an artificial lighting
system as would at first be supposed based merely upon what might
be termed daylight standards. When artificial light is required
to supplement inadequate daylight, however, then it becomes
more important to consider higher intensities of the artificial illu-
mination because of its direct competition under such circum-
stances with daylight values.

IITTEirSITY STANDARDS.

The whole question of intensity values to employ for any
given demands upon vision, such as those imposed by various
classes of work or different degrees of refinement in the discrim-
ination of detail in the objects looked at, is one which does not
yet seem to have been conclusively demonstrated. Illuminating
engineers, and in fact practically anyone who is called upon to
decide how much Hght to furnish for gpiven working operations,
usually depend upon their judgment, which is often based upon
conditions which have seemed satisfactory in other similar loca-
tions. This scheme is safe as far as it goes, but it is very difficult
to tell when a given system is satisfactory from every standpoint
of vision. I have seen a lighting system installed which was far
superior to the older system that it superseded, but which, at the
same time, was inferior to a still better system that was later
proposed. Here the employees thought the second improved sys-
tem was very satisfactory because of its comparison with a very
much inferior system. The judgment of , the employees here, if
taken on a basis of what was considered satisfactory, might have

Digitized by

Google

July, 1919.] Industrial Lighting. 85

been materially different from what it would have been had they
been asked for an opinion under a still more nearly ideal arrange-
ment of lamps.

I feel strongly that the specification of the proper quantity
of illiunination to use for varying visual demands is a matter
which is far from solved, and that probably the only way in
which it could ever be solved positively would be to take ophthal-
mological observations upon given observers under a given class
of work for different degrees of illumination intensity and over
sufficiently long periods to take into account the effects of the
illumination upon permanent depression of the eyesight. Tem-
porary judgments based on casual observations do not take into
account this factor of long continued use of the light and hence
lack at least one element involved. The excellent work of Ferree
and Rand at Bryn Mawr College has given to the lighting art
a good deal of useful information along this general direction.

SAFETY STAVDARDS OF IVTEITSITY.

There is another side of intensity specifications, however,
which can be approached with somewhat more confidence, and
this is the matter of providing enough light to safeguard employees
against accidents and to specify minimum values below which
manufacture^ cannot well be conducted without a likelihx)od of
time losses and inaccuracies in workmanship. The state codes
now in force in several of the states, which have been based on
the code prepared by the Committee on Lighting Legislation of
the Illuminating Engineering Society,^^ have included specifica-
tions on this minimum basis, and then usually add for each class
of work a higher value, which is headed as a desirable intensity.

In the preparation of tables of suitable intensities of illumina-
tion for all classes of work, and for the various ramifications of
manufacture, two difficulties present themselves, the one being
a lack of information on just what the illumination requirements
are for these almost infinite operations, with their varying shades
of form, color and detail, and the second being the cumbersome
extent of such a list which would endeavor to cover all cases.
In the original code of the Illuminating Engineering Society, all
industrial processes were summarized under the four heads: (a)
Storage, passageways, stairways, and the like; (&) rough manu-

" Mr. L. B. Marks, of New York City, Chairman.

Digitized by

Google —

86 C. E. Clewell. [JFI-

facturing and other operations ; (c) fine manufacturing and other
operations; and (d) special cases of fine work. Later, these
lists of classification groups have been elaborated somewhat,
although the Illuminating Engineering Society's code has been
based on this general scheme of classification through its revisions,
with the addition of several groups. There is a tendency m one
and another of the state codes to amplify the lists of operations
and to specify intensities for a larger number of detailed cases.

DISTRIBUTIOir AHD GLARE.

The question of how the light should be distributed over a
factory floor area is one which must be determined by the density
of the work and how near an approach may be desired towards
a perfectly uniform condition throughout the entire floor space.
Reflectors perform an important function in the correct dis-
tribution of light from lamps, which, by themselves, might not
result in nearly so satisfactory a lighting system.

The avoidance of glare is of the utmost importance, and has
already been touched upon. In its simplest form, the avoidance
of glare is approached by the workman when he surrounds his
otherwise bare local lamp with a piece of paper, or hangs up a
piece of cardboard in front of the lamp so as to prevent the strong
light of the lamp from shining directly into his eyes. From
several' standpoints, the proper attention to this feature in the
lighting system is one of the most important items of all, and
one authority has gone so far as to say, in effect, that if no other
improvements were made in existing systems of factory lighting
than the equipment of each lamp with a suitable reflector so as to
cut off from the eyes all direct rays from the brilliant filaments,
that considerable improvement would probably be made in the
reduction of industrial accidents. Obviously, the reduction of
eye strain and the improved workmanship, which such a course
would promote, would also be decided advantages.

XAINTBITAirCE OF THE SYSTEM.

The effects of light colored surfaces for walls, ceilings and
columns have long been recognized as quite a factor in the effec-
tiveness of lighting conditions, both natural and artificial. White
or light-tinted paints and frequent cleaning are two factors to
consider. The reader is referred to the lecture on the " Principles
of Interior Illumination," by Cravath, Harrison and Pierce, in

Digitized by

Google

July, 1919] Industrial Lighting. 87

the volume of lectures given under the joint auspices of the Uni-
versity of Pennsylvania, and of the Illuminating Engineering So-
ciety,** in which valuable data are given regarding the variations
in the utilization efficiency of various systems of light in its depend-
ence upon wall and ceiling conditions. One of the paint manu-
facturers has recently issued a readable bulletin under the heading
of " Barrelled Sunlight " which very appropriately emphasizes this
phase of factory lighting.

It will, perhaps, be seen that no lighting system can maintain
its original effectiveness unless the lamps and reflectors are cleaned
at proper intervals and unless burned-out lamps are renewed
promptly. This is of such fundamental importance to the con-
tinued success of any lighting system that some space might well
be devoted to the importance of maintenance and to methods for
conducting such work, in preliminary reports submitted to build-
ing owners on proposed lighting systems. Lamp and reflector
cleaning are items which are so readily overlooked that the average
user of light requires education along this line if his appreciation
of the needs of the case is to result in systematic adherence to the
work. One of the best plans I have ever seen of this kind is that
adopted some years ago at the East Pittsburgh Works of the
Westinghouse Electric and Manufacturing Company, where the
maintenance of the very large lighting system is conducted by a
special Division of the electrical department. Here, the original
plans of the work included systematic inspection of all lamps
each day for the purpose of locating every burned-out lamp and
ior noting equipment in need of cleaning. On the basis of these
daily inspection reports, the maintenance work may be conducted
effectively and a record can be kept of the costs for such work
which forms an interesting basis for a comparison between the
costs of the maintenance work and the gains produced by the
higher standard of illumination thus maintained.

STATE REGULATIOirS.

The original code of factory lighting issued by the Illuminat-
ing Engineering Society several years ago has since been used as
the basis for state regulations in Pennsylvania, New Jersey, Ohio,
New York and Wisconsin. Furthermore, the Committee on
Labor of the Advisory Council for National Defense issued

" Published by the McGraw-Hill Book Company, New York, 191 7.

Digitized by

Google

88 CE. Clewell. iJF.I.

through its Divisional Committee on Lighting ^* a code based quite
largely on that of the Illuminating Engineering Society. Many
of these codes contain modifications in the general arrangements
or in the addition of explanatory matter not found in the original
Illuminating Engineering Society's code, but the three funda-
mental items of intensity, distribution and the absence of glare
form, for the most part, an important place in all of these
regulations.

The issuance of the state codes has, of course, been based
on the safeguarding of employees and they have sought to reduce
accidents and to prevent premature eye trouble by the stipulation
of safe methods and amounts of illumination for various factory
operations. In one of the recent state codes, the factor of con-
serving time by permitting employees to do more and better work,
without additional effort, in a given time, through the medium
of better light, was emphasized as a factor which might influence
the wealth of the state.

Realizing that the state factory inspectors, upon whom the
application of these codes fall, would probably find difficulty in
gasping the full meaning of such rules because of the newness
of some of the ideas they contain, the University of Pennsylvania
invited state factory inspectors of Pennsylvania and of New Jer-
sey to a series of lectures on factory lighting at the University
in the spring of 191 8, and these proved to be very acceptable to
the state labor departments concerned. I am informed that the
Department of Labor of New Jersey is planning to continue this
general scheme of education among its factory inspectors by
lectures within the state from time to time.

Where intensity of illumination is specified, as in these rela-
tively new codes, the need of a simple device for the measurement
of illumination by relatively inexperienced people has been keenly
felt. The appearance of the small and very convenient " Foot-
Candle-Meter " (see Fig. 18), as a result of the work of Dr. C H.
Sharp, of New York City, has, in a way, met this need, and it is,
I believe, employed to a limited extent by the Departments of
Labor in Pennsylvania and New Jersey.

PROBLEMS ADDED BT THE WAR.

While the stress of war conditions is now largely over, it is
"Of which Mr. L. B. Marks, of New York, is chairman.

Digitized by

Google

July, 1919] Industrial Lighting. 89

interesting to review, in conclusion, a few of the things which
affected lighting practice due to those unusual conditions. One
of these, of course, was that of protective lighting about industrial
plants as a safeguard against damage to the plant, and this type
of illumination received a good deal of attention and was em-
ployed very effectively in many cases. Another was that of
lighting curtailment, as one of the points taken up by the Federal

Fig. 18.

Fuel Administration, and here, as previously stated, it was found
that of all the divisions of lighting, the industries were the one
field in which increases rather than curtailment in lighting were
desirable, thus emphasizing the importance with which the problem
of industrial lighting was viewed during the war as a strictly
war problem.

The emphasis which was placed upon good light by the Em-
ployment \Ianagement Division of the War Industries Board in
its efforts to educate employment managers under the intensified
training scheme then in vogue, and the hope which was entertained
that a high standard of working environment — that is to say, good
light, fresh air, adequate heat, cleanliness and neatness about the
Vol. 188. No. 1123—7

Digitized by

Google

90 C. E. Clewell. IJ- F- 1-

plant, and the like — would all go to prevent the excessive turn-
over of labor during the progress of the war in the war indus-
tries, all go to demonstrate the important place which industrial
lighting holds in the industrial field.

The foregoing notes, while not in any sense a scientific analysis
of factory lighting from the quantitative side, have given a general
outline of the factors involved in the problem. With these in
mind and thoroughly accepted and appreciated, the actual detailed
planning for industrial lighting systems possesses the possibility of
an interesting field for study and certainly contains an element
of compensation for those who devote time to such work, through
the beneficial effects which good lighting may accomplish for those
whose vision and whose workmanship depend to such an extent
upon facilities of this general nature

Salt Deposits of the United States. W. C. Phalex. ( U, S.
Geological Survey Bulletin No, 66p.) — The Delaware Indians made
salt from brine springs in New York State and sold it to settlers as
early as 1670, making probably the first commercial production of
salt in this country. The manufacture of salt by white people in the
United States was begun near Syracuse, N. Y., about 1788. Salt is
the most commonly used mineral in the world, and no useful mineral
except coal, perhaps, occurs in greater abundance or is more widely
distributed in the United States.

The Federal and State Surveys and private establishments have
published a great deal about the occurrence of salt in parts of the
United States, but not until now has so much information on the
salt deposits of the whole country been assembled in a single volume.
The distribution and character of the salt deposits are described
by States and a brief history of the industry is given, together with
a record of the output since 1797. The report also contains a dis-
cussion of the origin and formation of valine deposits and many
chemical analyses of brines and bitterns.

Wood Waste. (Weekly Nezvs Letter, U. S. Department of
Agriculture, vol. vi, No. 47, p. 5, June 25, 1919.) — A particularly
interesting field of possibilities for greater utilization of wood and
wood waste as a result of the Forest Products Laboratory's war work
is the use of built-up and fabricated construction. This is merely
utilizing small pieces of wood and a glue which will make a joint
as strong or stronger than wood, and building them up in the forms
desired. It was found, for example, that a laminated wing beam for
airplanes could be constructed as strong as a solid beam, and this at
once made possible a great increase in the utilization of spruce
material which otherwise had to be eliminated from aircraft
construction.

Digitized by

Google

HIGH FREQUENCY CURRENTS ON WIRES.*

J. O. MAUBORGNE, Lieut. Col., Signal Corps, U. S. A.

Attention was first directed, in 191 1, to the practical utility
of employing high frequency electric waves for transmission of
energy along wires by Major (now Major-General) George O.
Squier. The discussion following the publication of his results
indicated that, in the minds of many, the opinion prevailed, that
because of the excessive attenuation obtaining at the " ultra
audio " frequencies, the systeiji would be inoperative over great
distances. This was thought to be particularly the case if fre-
quencies greater than 100,000 cycles per second were employed.

Recently this subject has assumed an important aspect from
a military standpoint and it was decided to conduct further
experiments with the object of examining the possibility of adapt-
ing certain existing types of radiotelephone and telegraph appar-
atus to multiplex operation. The results of the few preliminary
tests which have been made recently by First Lieut. R. D.
Duncan, Jr., and Radio Engineer Samuel Isler of the Engineer-
ing and Research Division, Signal Corps, Washington, D. C,
are of interest because they have shown that not only is it possible
to transmit energy, at least in sufficient amounts to actuate stand-
ard " radio '* receiving apparatus, over comparatively long lengths
of wire circuits, but -that frequencies considerably in excess of
the value hitherto named as the upper limit could be employed.

The apparatus used in these tests is known as the SCR-67,
which is the ground set of the standard ground-airplane radio-
telephone equipment. It comprises two, three-electrode vacuum
tubes, of the transmitting type (Type VT-2. One oscillator and
one modulator) and connected circuit, a receiving tube (Type
VT-i) and circuit, and a two-stage audio frequency amplifier.
The method of modulation, that devised by Heising, is based
on the fact that, to a very close approximation, the amplitude of
the high frequency current is directly proportional to that of the

* Communicated by Maj.-Gen. George Owen Squier. An abstract of this
paper was presented at the Washington Meeting of the American Physical
Society, April 25, 1919.

Digitized by

Google

92 J. O. Mauborgne. [JF.I.

emf applied between the plate and the common filament terminal
of the oscillating tube; any variation of the emf, for example,
at an audio frequency, will modulate or mould the continuous
flow or high frequency energy in a corresponding manner, which
when received by a tuned receiving circuit and rectified, manifests
itself as an audible sound in a telephone receiver. The means
by which the modulation is accomplished is by a second tube,
whose plate filament path resistance is varied in accordance with
the speech frequencies applied to its input terminals. By prop-
erly interconnecting the plate or output circuits of the oscillating
and modulating tubes, and by further converting the high voltage
plate power supply to the two tubes from a constant potential
to a constant current system the variation in amplitude of the high
frequency current may be made to follow out faithfully the
variations impressed by the modulating source. This system is
advantageous since the completeness and purity of modulation is
practically independent of the frequency of the oscillating system.

The line may be connected to the source of oscillations in a
number of ways, of which probably the most convenient is by
inductive coupling.

To provide a practical means for carrying out of the tests, a
wire, running from Washington, D. C, to New York City, was
placed at the disposal of the Signal Corps by the Postal Telegraph
Company. This line was duplexed and was in continuous opera-
tion by the Postal Company. In the first series of tests one multi-
plex station was established at the Signal Corps Radio Laboratory,
Bureau of Standards, Washington, D. C, and a second at Dixon's
Park, Curtis' Bay, Md., approximately three miles from the Postal
office in Baltimore, the total wire distance between the two
approximating 60 miles. The multiplex apparatus was connected
to the line at these two points.

Satisfactory two-way communication was obtained; speech
was received at lx)th stations, loud and with exceptional clearness,
the distortion common and inherent to long distance wire tele-
phony being completely absent. The tuning at the receiving
stations was quite definite, comparable in every respect to that
when receiving signals of a " sharply '' tuned radio station. This
last fact permits of the operation of a number of multiplex units,
each tuned to a different frequency and without the use of filter
circuits on the same wire line. The carrier frequency employed
in these tests was 600,000 cycles per second (wave length 500

Digitized by

Google

July, 1919] High Frequency Currents on Wires. 93

metres) ; the effective line current, measured at each of the trans-
mitting stations, averaged 60 mil-amperes. Throughout the tests
the operation of the multiplex apparatus in no way interfered with
that of the wire telegraph apparatus nor. was interference experi-
enced from the latter.

The satisfactory range of an SCR-67, when operating as a
ground " radio-telephone " set, in communication with a corre-
sponding SCR-67, is, under ordinary conditions, 10 miles. Thus
by confining and directing the flow of energy to a definite direc-
tion, the range is materially increased.

The advantages of multiplex telephony and telegraphy are
many. From a military standpoint alone, it is obvious that in
time of war, any means of increasing the traffic handling capacity
of already overburdened telephone and telegraph lines will be of
inestimable value. There is a further advantage from an eco-
nomical standpoint, in that certain of the existing types of Signal
Corps radio-telephone and telegraph apparatus, large quantities
of which were purchased during the war and which are now
idle, with only slight changes in construction, may be adapted
to either radio or multiplex operation. The increased range
obtained makes possible the connection of outlying military posts
and establishments with low power units where ordinarily com-
paratively high power and consequently heavier apparatus would
be required if strictly radio communication were solely relied upon.

Office of the Chief Engineer,

Engineering and Research Division, Signal Corps.
Washington, D. C, April 5, 1919.

Tunneling Under the East River. (Scientific American, vol.
cxx, No. 26, p. 681, June 28, 1919.) — A very interesting bit of tunnel-
ing was recently done on the 14th Street tube under the East
River, New York. The heading was being run in rock and at one
point test holes showed a thickness of only eight inches of sound
dry rock above the line along which the top of the tunnel was to run.
As the tunnel was being driven without the use of compressed air
it was decided to drop the upper heading four feet until this thin
cover of rock was passed. The cast-iron lining was set in place at
each side of this section and then the rock was removed very care-
fully by using a great many holes each loaded with about one-eighth
of a stick of dynamite. As each bit of rock was removed to the
arch the tunnel fining was set in place. By this means the dangerous
section was tunneled without breaking through the thin shell.

Digitized by

Google

Current Topics. IJFI-

Simple Gage for Measuring Compressions. Axon. (Scien-
tific American, vol. cxx, No. i8, p. 453, May 3, 1919.) — One of the
most common causes of lost power in an automobile is that the
force of the explosion pressure depends upon compression pres-
sure before the gas is ignited. If the compression is 80 pounds
the explosive force acting against the piston top and imparting
power to it will be about 400 pounds per square inch. If worn
piston rings or leaky valves allow gas to escape when the piston
is rising on its compression stroke, the resulting decrease to 50 or
60 pounds means a reduction of explosive pressure to about 300
pounds per square inch. Besides this diminution in pressure, there
is a loss due to further leakage through the faulty retaining members.

A simple compression pressure indicating gage may be made
by taking an old spark plug body, from which the porcelain has
been removed and fit in a valve from a discarded inner tube by
pouring melted babbit metal or solder in to fill the space between
the spark plug shell and the valve. When the metal has set, the
valve is found to be firmly imbedded in the soft metal. The spark
plug is removed from the cylinder to be tested and the combina-
tion plug body and valve stem put in its place. As the engine is
turned over briskly by either the hand crank or self-starter by an
assistant, or the engine run slowly on the other cylinders, a tire
pressure recording gage held against the valve will record the
compression pressure just as it does air pressure inside a tire. If
the pressure is low on all cylinders it is a good indication that the
entire engine needs attention. It can be determined whether the
compression is adequate by comparison with the same tests on a
new car of the same model.

Failure of Concrete Stacks. Anon. (Power Plant Engineer-
ing, vol. xxiii, No. 12, p. 543, June 15, 1919.) — From the day con-
crete made its advent in building construction, its merits were
fully recognized. It must be admitted that for a large number of
structures there is actually no better material than concrete. It
became evident very soon, however, that it is an entirely unsuit-
able material for any purposes where it is subject to attack of
heat, products of combustion, or undiluted acids. One of the best
structures in which such conditions prevail is the chimney.

For the moment, we do not want to discuss those where the
structure collapsed during the construction or soon after. We
refer for the present only to those which decayed rapidly soon
after being put in use. The thin walls of the stack permitted
rapid radiation of heat. Condensation took place on the inner
side of the stack, and the condensate worked its way into the
fissures, rapidly destroying the texture of the material, and attack-
ing the reinforcing steel. The stacks started to lean, to burst
open, or collapsed entirely. Recently this inherent defect has
been in part overcome by using a lining of burned clay, extend-
ing the full length of the stack.

Digitized by

Google

RADIO TRANSMISSION FORMULAS FOR ANTENNA
AND COIL AERIALS.*

J. H. DELLINGER,

Bureau of Standards.

The aerial of a radio transmitting or receiving set is either a
condenser or an inductance coil of large dimensions. It effects
the transfer of power between the radio circuits and the ether.
The coil aerial has the inherent advantage of serving as a direction
finder and interference preventer, but is less effective quantitatively
as a transmitting or receiving device than the condenser aerial
commonly called the antenna. The practical question, how far
can communication be maintained by a coil in comparison with an
antenna, is answered by the following formulas, derived from
electromagnetic theory. A flat-top antenna is considered, and a
rectangular coil. Let h = height of antenna or coil, / = horizontal
length, and N = number of turns of wire of coil aerial, / = cur-
rent, A = wave length, d = distance apart of transmitting and re-
ceiving aerials, /? = resistance of receiving aerial circuit. The
subscripts s and r refer to sending and receiving, respectively. All
lengths are in meters.

Antenna to antenna:

1 88. hshrls

J. r

RXd

Antenna to coil:

/r =

1 184. hshMNrh

Coil to antenna :

/r =

1 184. UshrNsIs

RKH

Coil to coil :

,, _ 7450. hAshrlrNsNrls

R\*d

These formulas were derived by the author two years ago and
have been found useful in the Signal Corps and Navy work since

♦ Communicated by the Author. Complete paper to appear as a Scientific
Paper of the Bureau of Standards.

Digitized by

Google

96 J. H. Bellinger. [JF. T.

that time. Either the equations as here given or the component
equations giving the field produced by a given antenna or coil
aerial and the received current produced by a given field, lead to
the solution of questions of design which it would be difficult to
settle by experiment. Such quantitative experiments as have been
made have verified the formulas to 25 per cent, or better, some
observed values of received current being higher and some lower
than the theoretical values.

The actual current received when a coil aerial is used is fre-
quently greater than the formulas indicate, because such an aerial
acts both as a coil and as an antenna by virtue of its capacity to
ground. This double action of the coil structure is likewise indi-
cated by values obtained for radiation resistance and by the ob-
served directional properties.

The use of the coil aerial is particularly advantageous, as may
be seen from the formulas, for short waves. In most cases, the
usefulness of the coil increases as its dimensions are made to ap-
proach the order of magnitude of the wave length. An advantage
of the coil not apparent from the formulas is that its resistance
can usually be made lower than that of the corresponding antenna.

Bureau of Standards,
April 25, 191 9.

Waterproof Glues in Automobile Manufacture. Anon.

(Forest Products Laboratory, Madison, Wisconsin, Technical Notes
No. F-14.) — Some of the new waterproof glues developed pri-
marily for aircraft purposes during the war offer the possibility
of overcoming a difficulty that has proved very annoying, both to
the automobile owner and to the manufacturer, wherever lino-
leum is used on the running boards or as a covering for the floor
of the car. Ordinary glues which are soluble in water are not
very effective in cementing linoleum, and most automobile
owners have soon discovered that the glue disintegrates and the
linoleum comes loose after the car has been washed a few times.
Casein glues are admirably adapted to this purpose, and if
the quality is right and they are properly applied the linoleum
should give no trouble during the life of the car. Casein glues
are exceedingly resistant to the action of water and retain 9
very high percentage of their original strength, even after lonf
immersion under water. They are comparatively inexpensive,
and the materials from which they are made are readily available
in the market. They are applied cold and will set w^ithout the
application of heat.

Digitized by

Google

PRESENTATION OF THE FRANKLIN MEDAL.
MAY 21, 1919.

At the Stated Meeting of the Committee on Science and the
Arts, held March 5, 1919, the following resolutions were adopted:

" Resolved, That the Franklin Medal be awarded to Sir James Dewar, of
London, England, in recognition of his numerous and most important contribu-
tions to our knowledge of physical and chemical phenomena, and his great
skill and inventive genius in attacking and solving chemical and physical
problems of the first magnitude."

" Resolved, That the Franklin Medal be awarded to Major General George
Owen Squier, in recognition of his valuable contributions to physical science,
his important and varied inventions in multiplex telephony and telegraphy and
in ocean cabling and directing the Air and Signal Services of the United States
Army in the World War."

CORRESPONDENCE WITH MEDALISTS.

The Franklin Institute

of the state of pennsylvania

Philadelphia

OFFICE OP THE SECRETARY

April 8, 191 9.
Major General George Owen Squier,
Chief Signal OMcer, U. S. Army,
War Department,

Washington, D. C.
Sir:

I have the honour to inform you that The Franklin Institute has awarded
you The Franklin Medal, founded for the recognition of those workers in
physical science or technology, without regard to country, whose efforts in
the opinion of the Institute have done most to advance a knowledge of physical
science or its applications. The award is minuted as follows:

" That The Franklin Medal be awarded to Major General George
Owen Squier, in recognition of his valuable contributions to physical
science, his important and varied inventions in multiplex telephony
and telegraphy and in ocean cabling, and his eminent success in or-
ganizing and directing the Air and Signal Services of the United
States Army in the World War."

The medal and accompanying certificate are being prepared, and I am
requested, on behalf of our Management, to extend to you a cordial invitation
to come to the Institute on the afternoon of Wednesday, May 21st, to receive
this medal and certificate from our President.

A second medal has been awarded to Sir James Dewar, of the Royal
Institution, London, and the Earl of Reading has been asked to come to the
Institute at the same time to receive it for Sir James.

Digitized by

Google

98 Presentation of Franklin Medal. [J- ^' I-

MAJOR-GENERAL GEORGE OWEN SQUIER. Ph. D.
.Chief Signal Officer. U. S, Army.
FRANKLIN [MEDALIST. 1919.

Digitized by

Google

July, 1919.] Presentation of Franklin Medal. 99

You and Lord Reading will be asked to be guests of honour at a dinner
to be given on the same evening, but in this connection our President, Dr.
Walton Clark, will communicate further with you.

/ I am, ~ ~ "

Respectfully,

(Signed) R. B. Owens,
RBO :S Secretary.'

The Franklin Institute 1

of the state of pennsylvania
Philadelphia

OFFICE OF THE SECRETARY ApRIL 9, I9I9-

Sir James Detvar, D.Sc, LL.D., F.R.S.,
The Royal Institution,
Albemarle Street,

London, Wi, England.
Sir:

I have the honour to inform you that The Franklin Institute has awarded
you The Franklin Medal, founded for the recognition of " those workers in
physical science or technology, without regard to country, whose eflForts. in the
opinion of the Institute have done most to advance a knowledge of physical
science or its applications." The award is minuted as follows : ,

" That The Franklin Medal be awarded to Sir James Dewar, of
London, England, in recognition of his numerous and most important
contributions to our knowledge of physical and chemical phenomena,
and his great skill and inventive genius in attacking and solving chemi-
cal and physical problems of the first magnitude."

The medal and accompanying certificate are being prepared, and the Earl
of Reading, your Government's Ambassador Extraordinary and Plenipoten-
tiary at Washington, has been requested to come to the Institute on the after-
noon of Wednesday, May 21st, to receive this medal and certificate, on behalf
of his Government, for you. j

I am,' ;

Respectfully,

(Signed) R. B. Owens,

RBO:S Secretary,

1
The Franklin Institute I

OF THE state OF PENNSYLVANIA i

Philadelphia •

OFFICE OF THE SECRETARY ApRIL 9, I9I9.!

The Earl of Reading, Ambassador Extraordinary,
and Plenipotentiary of His Britannic Majesty,
British Embassy,

Washington, D. C.
Your Excellency:

I have the honour to inform you that The Franklin Institute has awarded
to Sir James Dewar, of London, England, The Franklin Medal, founded for
the *' recognition of those workers in physical science or technology, without

Digitized by

Google

lOO Presentation of Franklin Medal. [J. F.I.

SIR JAMES DEWAR. D. Sc, LL.D.. F. R.S.

Jacksonian Professor of Experimental Philosophy, University of Cambridge ;

Fullerian Professor of Chemistry. Royal Institution, London.

FRANKLIN MEDALIST, 1919.

/^^

Digitized by

Google

July, 1919.] Presentation of Franklin Medal. loi

regard to country, whose efforts in the opinion of the Institute have done most
to advance a knowledge of physical science or its applications." The award
is minuted as fellows :

"That the Franklin Medal be awarded to Sir James Dewar, of
London, England, in recognition of his numerous and most important
contributions to our knowledge of physical and chemical phenomena,
and his great skill and inventive genius in attacking and solving chemi-
cal and physical problems of the first magnitude."

The medal and accompanying certificate are being prepared, and I am
requested, on behalf of our management, to extend to you a cordial invitation
to come to the Institute on the afternoon of Wednesday, May 21st, to receive
this medal and certificate from our President, on behalf of your Government,
for Sir James.

A second medal has been awarded to Major General George Owen Squier,
Qiief Signal Officer, United States Army, in recognition of his scientific and
technical achievements, especially with relation to communications.

You and Major General Squier will be asked to be guests of honour at a
dinner to be given on the same evening, but in this connection our President,
Dr. Walton Gark, will communicate further with you.

I am, "

Your Excellency's very humble servant, ^

(Signed) R B. Owens,
RBO :S Secretary.

War Department

office of the chief signal officer

Washington

April ii, 1919.
Major R. B, Owens,

Secretary, The Franklin Institute,
Philadelphia, Pa.
Sir:

I have the honor to acknowledge the receipt of your communication of
April 8, 1919, advising me that The Franklin Institute has made an award to
me of The Franklin Medal.

Allow me to express my deep appreciation of the very great honor con-
ferred upon me by the Institute through this award.

It gives me great pleasure to accept, subject to the exigencies of the public
service, the very cordial invitation which you have extended to me, to come
to the Institute on the afternoon of Wednesday, May 21, 1919, to receive this
medal and certificate from your President.
I remain.

Faithfully yours,

(Signed) George O. Squier,

Major General,
Chief Signal Officer of the Army,

Digitized by

Google

I02 Presextatiox of Franklin Medal. U- f • ^^

British Embassy
Washington

April 12, 1919.
Dear Mr. Owens :

I beg to acknowledge the receipt of your letter of April 8th in which you
are so good to inform me of the award of The Franklin Medal to Sir James
Dewar. It is naturally a great pleasure to me to learn of the decision of The
Franklin Institute to confer this honour upon Sir James Dewar, and I trust
you will be good enough to convey to the members of the Institute the appre-
ciation which I am sure will be generally felt in Great Britain at this recog-
nition of the work of a British man of science.

I fear that it will not be possible for me to accept your kind invitation to
visit the Institute on May 21st in order to receive the Medal and Certificate
for Sir James, as I shall have left this country by the date in question unless
some unexpected alterations should be made in my plans. The Embassy will,
however, be only too glad if they can be of service to you for forwarding this
Medal to London.

Believe me,

Very truly yours,

(Signed) Reading.
R. B. Owens, Esq.,

Secretary, The Franklin Institute,
Philadelphia,

Pennsylvania.

Western Union Cablegram.

London, April 21, 1919.
The Secretary Major Ozvens,

The Franklin Institute (15 S. 7st),
Philadelphia,

Convey to Council grateful appreciation for award of The Franklin
Medal. Regret cannot receive it personally owing to poor health. Will write.
Accept personal regards.

Dewar.

The Franklin Institute
of the state of pennsylvania
OFFICE OP THE SECRETARY Philadelphia

April 25, 1919.
Major General James Douglas McLachlan.
Military Attache, British Embassy,
Washington, 1). C.
Sir:

I have the honour to inform you that The Franklin Institute has awarded
to Sir James Dewar, of the Royal Institution, London, England, The Franklin
Medal, founded for the " recognition of those workers in physical science or
technology, without regard to country, whose efforts in the opinion of the

Digitized by

Google

July, 1919.] Presentation of Franklin Medal. . 103

Institute have done most to advance a knowledge of physical science or its
applications." The award is minuted as follows:

" That The Franklin Medal bs awarded to Sir James Dewar, of
London, England, in recognition of his numerous and most important
contributions to our knowledge of physical and chemical phenomena,
and his great skill and inventive genius in attacking and solving
chemical and physical problems of the first magnitude."
The medal and accompanying certificate are being prepared, and I am re-
quested, on behalf of our management, to extend to you a cordial invitation
to come to the Institute on the afternoon of Wednesday, May 21st, to receive
this medal and certificate from our President, on behalf of your Government,
for Sir James.

A second medal has been awarded to Major General George Owen Squier,
Chief Signal Officer, U. S. Army, in recognition of his scientific and technical
achievements, especially with relation to communications.

You and Major General Squier will be asked to be guests of honor at a
dinner to be given on the same evening, but in this connection our President,.
Dr. Walton Clark, will communicate further with you.

I am.

Respectfully,

(Signed) R. B. Owens,
RB0:S _ Secretary^

The Military Attach fe
BRmsH Embassy

Washington, D. C, 28 April, 1919.
My dear Mr. Owens :

Owing to my temporary absence from Washington on duty your letter of
the 25th of April has only just reached me. I am very pleased to learn from
it that The Franklin Medal has been awarded to Sir James Dewar, of the Royal'
Institution, London, England; and I am very flattered at being invited to
receive from your President on behalf of the British Government the medal and
certificate awarded to Sir James Dewar.

I much regret that Lord Reading, the present British Ambassador, sails for
England on the 3rd of May, and is therefore unable to represent the British
Government at Philadelphia on the 21st of May. I should esteem it a
favour if you would convey to the President and Members of the Franklin
Institute my high appreciation of the honour they have done me in selecting^
me to take Lord Reading's place on the 21st of May, and my grateful ac-
ceptance of their kind invitation.

With the assurance of my high esteem,
I am.

Yours very sincerely,

(Signed) James D. McLachlan,
Major General.
Mc/P British Military Attache

R. B. Owens, Esq.,

The Franklin Institute,
Philadelphia, Pa.

Digitized by

Google

I04 Presentation of Franklin Medal. [JF. I.

PROGRAMME OF MEETING, MAY ai, 1919.

Presentation of The Franklin Medal to Major General James Douglas
McLachlan, C.B., D.S.O.. on behalf of His Britannic Majesty's
Government for Sir James Dewar, D.Sc, LL.D., F.R.S.; Jack-
sonian Professor of Experimental Philosophy, University of
Cambridge; Fullerian Professor of Chemistry, Royal Institution,
London.

Presentation of The Franklin Medal to Major General George Owen
Squier, Ph.D., Chief Signal Officer, United States Army.

Address :

" Some Aspects of the Signal Corps in the World War." By
Major General Squier.

PRESENTATION OF THE FRANKLIN MEDAL TO SIR JAMES
DEWAR AND MAJOR GENERAL GEORGE OWEN SQUIER.

In calling the meeting to order the President of the Institute
announced that the business of the meeting would be the annual
presentation of the Institute's highest award, The Franklin Medal,
in recognition of distinguished scientific and technical achieve-
ment, and recognized Dr. Harry F. Keller, who made the follow-
ing statement relative to the work of Sir James Dewar :

Mr, President: It was at the May meeting of the Institute,
1 9 14, that you presented the first impressions of the beautiful
Franklin Medal to two illustrious men of science. This precedent
has since been followed, and so we meet here today for the fifth
time to pay our tribute to a pair of savants who in the judgment of
the Institute have done most to advance our knowledge of physical
science. As chance would have it on the present occasion the time
could not have been chosen more happily ; for in these days of May
our Nation is jubilantly celebrating the return of her heroic sons
and exultantly looking forward to the early conclusion of a glor-
ious peace.

And I regard it as a very special and rare privilege, Mr. Pres-
ident, to have been asked to present to you as The Franklin
Medalists two scientists who have not only made abundant contri-
butions to our knowledge of physical phenomena, but who also by
their great achievements have so conspicuously helped our countr}-
and its associates in winning the war. It seems, moreover, pecul-
iarly fitting that one of the medalists should be a native and
citizen of Great Britain, while the other was bom and bred an
American.

Digitized by

Google

July, 1919] Presentation of Franklin Medal. 105

In accordance with its established custom the Committee on
Science and the Arts has based its recommendations upon the
recognition of work in both pure science and applied science, with-
out, however, drawing a sharp line of demarcation. For, well-
defined as this line appeared before the war began, it has been
largely obliterated during the years of the war, when scientists
made patriotism their highest aim, and unstintingly gave their
services to their Governments, accomplishing feats which in other
times would have seemed impossible.

The first of these medals is to be conveyed to a man whose
name for two generations past has been one to conjure with in the
camps of chemists and physicists. Sir James Dewar is universally
recognized as one of the foremost leaders in the two branches of
physical science, and the great wealth of contributions he has made
to both includes discoveries and inventions of the highest value
and in many fields of research.

Like so many famous men of science, he is a native of Scotland.
Bom at Kencardine-on-Forth, September 20, 1842, he received
his training in the sciences at Dollar Academy and the University
of Edinburgh. It was in the latter institution, in 1863, that he
became assistant to Sir Lyon Play fair, the Professor of Chemistry.
In 1868 he spent a few months at the University of Ghent, Bel-
gium, where the brilliant researches of A. F. Kekule were then
attracting the attention of all workers in organic chemistry.

The scientific career of Sir James Dewar presents itself as a
long, unbroken, and almost unparalleled series of triumphs in
experimental research. It would be difficult indeed to name an-
other investigator of our time who has to his credit a like rich
harvest of discoveries and inventions. The time allotted me here
is scarcely sufficient to permit even the briefest reference to his
more important achievements. He is one of the few great scien-
tists who have not been hampered in devoting their careers
entirely to experimental inquiry. As I have already stated, the
subjects of his pursuits lie in the fields of chemistry and physics,
or on the border-lands of these sister sciences.

In the earlier years of his career he directed his attention
mainly to the coal tar bases, and among the researches he made at
this time those on pyridine, quinoline, and their numerous deriva-
tives, were the most notable and important. With the experience
Vol. i88. No. 1123— 8

Digitized by

Google

io6 Presentation of Franklin Medal. [JF-I.

gained in this line of work he tlien engaged in the study of modern
high explosives, and as a member of the Government Explosives
Committee, he invented, jointly with Sir Frederick Abel, the
smokeless powder, cordite, which is the powder used by the British
Government.

But the most extended and most fruitful researches of our
medalist are undoubtedly those in which the effects of low temper-
atures were brought to bear on the properties of matter. Not only
was he one of the pioneers but in many respects also the most suc-
cessful experimenter in the field of low-temperature research. He
was the first to liquefy atmospheric air on a larger scale and it
was he also who made liquefied gases, like oxygen, nitrogen, hydro-
gen and fluorine, available for scientific use. By evaporating
liquid hydrogen under reduced pressure he succeeded in obtaining
solid hydrogen. Most remarkable results were obtained by sub-
jecting various substances to very low temperatures. Thus liquid
oxygen was found to be strongly magnetic ; pure metals at tem-
peratures approaching absolute zero became almost perfect con-
ductors of electricity; and by the use of charcoal as an absorbing
agent for gases at extremely low temperatures the highest vacua
were attained. By means of charcoal also gases like hydrogen,
helium and neon were separated from the air, and in 'this way
highly important information was obtained as to the constitution
of atmospheric air.

The inventive genius of Sir James Dewar was strikingly shown
in the construction of the new and very elaborate devices employed
by him in the liquefaction and solidification of various gases. The
silvered vacuum- jacketed vessel, the Dewar flask, is now manu-
factured on a large scale for keeping hot and cold liquids for long
periods of time under the name of Thermos bottles.

The great versatility and resourcefulness of Sir James and his
prodigious capacity for work are further reflected by the great
number of researches in which he was associated with other dis-
tinguished scientists. They embrace a great variety of subjects in
the domains of inorganic and organic chemistry, physics and
physiology. Among them special mention should be made of the
very extended researches in spectroscopy with George Downing
Liveing; the difficult and successful experiments on the lique-
faction of fluorine with Henri Moissan; the determination of
atomic and molecular constants with William Dittmar and with

Digitized by

Google

July, 1919] Presentation of Franklin Medal. 107

Alexander Scott; and studies on the physiological action of light
and various chemical agents with John Gray McKendrick.

Advancing years have not impaired Sir James' enthusiasm for
research, nor his skill and cunning as an experimenter. In recent
years he has made many* notable contributions to our knowledge
of the radioactive substances, and has successfully solved also
various problems of capillarity and surface tension. Truly sen-
sational were his experiments with the stable and long-lived soap
bubbles blown in a cryophorus vacuum or in perfectly pure air.
They were photographed by him in their natural colors and in
various stages of development, appearing uniformly black when
the final stage of tenuity was attained.

That the scientific institutions and societies of all countries
should have vied with each other in lavishing their highest honors
upon a man who has done such marvelous things goes without
saying. I shall not attempt to enumerate the many positions of
trust and honor he has graced with his incumbency, nor the
medals, prizes, and degrees that have been bestowed upon him.
We rejoice that as the last but not least of the long list we may
now add The Franklin Medal, and that this award is so highly
appreciated by the recipient. Unfortunately, as he has cabled the
Institute, he is prevented by illness to receive it in person, but we
are honored by the presence of a distinguished representative of
the British Government, who on behalf of the latter will receive
the medal for Sir James Dewar. I have the honor, Mr. President, to
present to you Maj.-Gen. James Douglas McLachlan, C.B., D.S.O.

The President, in presenting The Franklin Medal to Major-
General McLachlan, said:

General McLachlan, the members of The Franklin Institute
are appreciative of the distinction conferred upon this meeting by
the presence of a representative of the Government of Great
Britain ; and we thank you personally, Sir, for coming to have a
share in our simple ceremony.

The Franklin Institute, having awarded to your distinguished
countryman. Sir James Dewar, in recognition of his services to
mankind rendered in the field of science, The Franklin Medal and
Diploma, and a certificate of Honorary Membership in T^he
Franklin Institute, it becomes my duty and privilege to present to

Digitized by VrrOOQlC

io8 Presentation of Franklin Medal. [J- F. I.

you this Medal and these documents for transmission to Sir James
through the State Department of your Gracious Sovereign. These
awards constitute the highest honor in the gift of the Institute.

In accepting the medal for Sir Janids Dewar, Major-General
McLachlan said:

Mr, President, Members of The Franklin Institute, Ladies and
Gentlemen: I much appreciate the honor that has been done me
in inviting me to accept on behalf of The British Government The
Franklin Medal awarded by The Franklin Institute to Sir James
Dewar. And I should like to express to you how sorry Lord
Reading was that he had to sail for England before the date fixed
for this ceremony. His commanding presence and his eloquence
would have been a much finer means than any words of mine for
expressing the pleasure and gratification of the British Govern-
ment and the British nation at the signal honor done to British
Science by the award of this medal to Sir James Dewar. For this
is the first time that this high distinction has been awarded to a
British subject, and for that reason both I and my country are
indeed proud today.

The work and scientific achievements of Sir James Dewar
have been set forth in detail by Dr. Harry F. Keller, and I shall
not repeat them. But in the minds of soldiers the name of James
Dewar will always be associated with two things, firstly, the
Thermos flask which he invented, and secondly, the smokeless
explosive Cordite, of which he and Sir Frederick Abel were
co-inventors.

As a soldier and a Scotsman it gives me great pleasure to
receive for Sir James Dewar this medal. For he is a Scotsman
and a countryman of mine, and it was in Edinburgh that he first
began his studies of chemistry under Lord Playfair.

And another reason why I am glad to have an opportunity
of speaking to you today is this: This war has shown how
absolutely essential it is to make the fullest use of the chemical,
metallurgical, manufacturing and engineering resourtes of a
country in order to ensure success in war. To ensure success in
modem warfare all the resources of the country must be utilized
strictly for war purposes. If you will look through the mem-
bership list of The Franklin Institute you will see how large a
number of the members gave their services to the Government

Digitized by

Google

July, 1919] Presentation of Franklin Medal. 109

at a time when technical experts such as they were urgently
needed. I select two names, the first to come into my mind, that
of General Atterbury, who served as Director-General of Rail-
ways in France, and that of Mr. Vauclain, Vice-President of the
Baldwin Locomotive Works, who did such splendid work on the
War Industries Board in Washington and with whom I was con-
stantly in close touch during the war. I know that many other
members of The Franklin Institute did equally good work, but I
merely mention these two names as typical of the work done
by members of The Franklin Institute during the war ; and it is
of great value to any Government to have an Institute such as this
whose members have the technical knowledge of chemical, metal-
lurgical, engineering and manufacturing questions which is indis-
pensable for the adequate carrying on of a great war.

Lastly, I am very glad to have the chance of witnessing the
presentation of the medal of The Franklin Institute awarded
to my old friend and companion in arms Major-General Squier.
It has been my good fortune to know General Squier for over
eight years, both in this country and in England, and in addition
to the other bonds of friendship that unite us we both had the
good fortune to serve in France with the original Expeditionary
Force in 191 4. For that reason I am particularly glad to be
here this aiternoon.

I take this opportunity of expressing to you the thanks of
Sir James Dewar and of Great Britain for the honor thus con-
ferred for the first time on a citizen of the British Empire. May
it cement still further the friendship between the two great
English-speaking nations, and may we, together with those great
Nations alongside of whom we have fought and won the great
struggle in defence of the liberties of the world, may we, I say,
all continue to work together in the arts of peace and civilization
as successfully and whole-heartedly as we have fought together in
the recent great war.

Dr. Keller was again recognized, and presented the following
statement of the work of Major-General Squier:

Mr. President: It is a well-known fact that under the stress
of great national crises individuals are often stimulated to almost
superhuman performance, and that tasks which in normal times
it would require decades to accomplish, are then done, and well

Digitized by

Google

no Presentation of Franklin Medal. [J- F.I-

done, by such men in a few months or years. The great war
which has just come to an end has furnished many instances
of this sort, but few so remarkable as that of the scientist to
whom you are about to present the other impression of The
Franklin Medal. By natural inclination as well as by training
a military man and a scientist, he achieved such distinction in both
capacities that at the time when our country entered the great
war he was chosen for the gigantic dual task of building up our
Air Fleet and of providing the field telephone and wireless com-
munications for our armies. How nobly and we!l he acquitted
himself of these responsibilities I need not tell you or an audience
such as this. I cannot refrain, however, from expressing the
thrill of pleasure I experience in presenting to you for the highest
award of the Institute a man who has so magnificently served our
Country in the great crisis.

Our medalist, Major-General George Owen Squier, Ph.D.,
is still in the prime of life, and we may well hope and expect that
in the years to come he shall gather many laurels to add to those
he has won in the war and before it. He was bom at Dryden,
Mich., on March 21, 1865. He received his military training at
the U. S. Military Academy, West Point, N. Y., and it was
there that he first showed his decided bent toward mathematical
and scientific studies. After his graduation in 1887 he was
appointed second lieutenant in the Artillery, and shortly after-
wards sent for duty to Fort McHenry, at Baltimore, Md. I ven-
ture to say that no assignment could have been made more
welcome to the young officer who so ardently aspired to be a
physicist. For, close at hand, at the Johns Hopkins University,
the chairs of physics, chemistry and astronomy were then held
by a trio of the most eminent exponents of physical science, vis.,
Henry Rowland, Ira Remsen, and Simon Newcomb. And he
lost no time in taking advantage of his opportunities, nor were
the teachers slow in recognizing the exceptional ability and great
promise of their soldier-student. In all three cases the relations
between teacher and student were destined to grow into lasting
friendships, while the young officer was laying the foundations
for those inventions which have since made him famous as
a physicist.

His first important contribution to science was a research on
" Electrochemical Eflfects due to Magnetization," published in

Digitized by

Google

July, 1919] Presentation of Franklin Medal. hi

1893. Four years later he wrote, jointly with Dr. A. C. Crehore,
of Dartmouth, a mathematical paper entitled " Currents in
Branches of a Wheatstone's Bridge," and about this time he
engaged, partly by himself, and partly in conjunction with Dr.
Chehore, in a series of investigations relating to applications of
physics to military service. Among the numerous important
results of these were the invention of a New Range and Position
Finder and the Synchronograph. The latter marked a great step
forward in the rapid transmission of intelligence, being based
on the use of the alternating current with the polarizing photo-
chronograph as receiver. But this was only the beginning of a
great series of achievements by which our medalist advanced
and improved the methods of telegraphy and telephony. The
"wired-wireless," first proposed by him in 191 1, has proved, espe-
cially in military field operations during the war, to be invaluable
as a means of sending intelligence and commands. As the name
implies, it is a method of telegraphing or telephoning by means
of electrical waves guided by wires. In this way as many as a
half dozen messages may be sent along a telephone wire, but
outside of it, at the same time, and without interfering with the
use of the wire for ordinary service. The messages, however,
must be tuned to different frequencies and be received by separate
receivers. One great advantage of this system is that the waves
will still travel along the wire when it is broken and jump gaps
in it of fifty feet and more. The " wired-wireless " method of
multiplex telegraphy and telephony has recently been adapted and
developed for commercial purposes and has proved especially
useful on long open wire lines. During the last few years our
medalist has devised a new method of ocean cabling which is now
in successful operation, effecting a very considerable increase in
the capacity of the existing cables. This remarkable stride in
cable transmission was made by substituting for the cable " curve,"
made by opening and closing the circuit, a single-phase alternating
current of the sine wave type, operating with the Morse code.

The wire and wireless inventions made by General Squier are
bewildering in their variety and number. They extend over the
entire range of the transmission of intelligence on land, under the
sea and in the air. His studies on the absorption of electro-
magnetic waves by living organisms led, among other things, to
the use of trees as antennae in wireless telegraphy and the con-

Digitized by

Google

112 Presentation of Franklin Medal. [J- F. I-

struction of a new listening device, the " floraphone/* It was he
also who laid the inter-island cable in the Philippines, in 1900,
and who drew up the first specifications of a military airplane ever
issued by any government. What he did in building up our air
fleet and as Chief Signal Officer in our army is too well known
to require any commentary at this time and before this audience.

Nor is it necessary for me to recite here the many steps of
his promotion from second lieutenant to his present rank of
Major-General, which have attended his most brilliant and event-
ful career in the Army.

Until a few days ago we had confidently expected that General
Squier would be with us on this occasion. I know he was look-
ing forward to it with genuine pleasure, but he has quite unexpect-
edly been ordered abroad. In his absence Dr. F. P. Keppel,
Assistant Secretary of War, has kindly consented to come here
from Washington to receive the Franklin Medal for him. I have
the honor, Mr. President, to introduce to you Dr. Keppel.

The President then said :

Dr, Keppel, the members of The Franklin Institute are ap-
preciative of the honor conferred upon this meeting by the pres-
ence of a representative of the War Department of our National
Government; and we thank you personally, Sir, for coming to
have a share in our simple ceremony.

The Franklin Institute, having awarded to our countryman,
Major General George Owen Squier, in recognition of his services
to our country and to humanity, rendered in the field of science,
The Franklin Medal and Diploma, and a certificate of Honorary
Membership in The Franklin Institute, it becomes my duty and
privilege to present to you this Medal and these documents for
transmission to General Squier through the War Department of
our National Government. These awards constitute the highest
honor in the gift of the Institute.

Dr. Keppel, in accepting the medal for Major General Squier,
expressed the pleasure which the War Department felt in having
the life-work of General Squier recognized by the highest award
in the gift of the oldest institution in America devoted to the de-
velopment of physical science and its application, and to the en-
couragement of those whose researches and inventions have
served as milestones in the progress of civilization.

Colonel M. McK. Saltzman, Acting Chief Signal Officer, then
read the following paper for the medalist :

Digitized by

Google

July, iQip] Presentation of Franklin Medal. 113

SOME ASPECTS OF THE U. S. SIGNAL SERVICE IN
THE WORLD WAR,

GEORGE OWEN SQUIER, Ph.D.

Major-General. Chief Signal Officer U. S. Army.

It is with the keenest regret that I find it impossible to be
present at the Hall of The Franklin Institute on the afternoon
of the 21 St of May to receive at the hands of our President The
Franklin Medal.

Nothing short of a sudden call for overseas service, from the
Commander-in-Chief himself, would have prevented me from
being present in person to receive this signal honor from our
venerable Institution.

Had I been present you would have expected me, no doubt, to
give very briefly the underlying principles which have guided those
of us in authority in the making of that part of our expeditionary
forces which has to do with the transmission of intelligence
in all of its ramifications of personnel and materiel.

This is not the time nor the place to speak in detail of that
great enterprise. In the fulness of time these details will be
preserved as they should be in the archives of our country. It
manifestly can be done only when we can add to the accomplish-
ments of this side of the Atlantic the details of the work of the
Signal Corps in actual combat and in the equally important net-
work of communications behind the lines which has been built up
not only in France but in England, Italy and Russia and wherever
American soldiers have been sent for duty.

It would be quite impossible to mention either the names or the
accomplishments of the 2712 officers and the 53,277 men who have
been engaged in this great work. Where names are mentioned
it is purely incidental to illustrate a point.

This famous Institute itself contributed a conspicuous part
in this enterprise. In the early days of the war this Institute for
a time was turned into a veritable recruiting station for the Signal
Corps, and some 2000 officers and men were by this means avail-
able to the Signal Corps, thus gaining most precious time.

The importance of inter-communication in warfare cannot
well be exaggerated. The element of time is a controlling one in
strategy and tactics, and as the distances become greater the elec-
trical method of inter-communication surpasses all others in

Digitized by

Google

114 Presentation of Franklin Medal. [J. P^L

increasing ratio. Unity of Command, which the Allies were so
slow in realizing, can reach its full value only when the most
perfect system of inter-communication is established and main-
tained between general headquarters and the larger units and
between these and the smaller units to the man on the firing line.

The enormous size of modern armies and vast terrain over
which they must operate only accentuates the importance of the
intelligence transmission system.

History records from the earliest times the development step
by step of methods of signaling. It is known, for instance, that
the Indians who inhabited this continent prior to its discovery by
Columbus had certain efficient methods of signaling unknown to
us at present.

As civilization has progressed science has been called upon at
each step to contribute additional means of communication
between .individuals or groups.

Undoubtedly the most efficient method of signaling yet
devised is the spoken word which we employ hourly to signal
our thoughts in every shade of their meaning.

The telephone art, which stands to-day as a monument to
American genius, and every essential feature of which can be
traced to American origin, is efficient over all others for the
fundamental reason that it vastly extends the reach of the human
voice and permits the use of language directly in signaling. This
means that practically every individual is an expert signalman,
and in the United States there is no region so remote but that it
may not be joined at present to any other region by direct speech.

The advances in radio telephony and telegraphy where the
ether of space becomes a common ** party line " for all, and par-
ticularly the linking up of these ether circuits to the great wire
systems of the world, protends the day which I believe is not far
distant, when we can reach the ultimate goal so that any individual
anywhere on earth will be able to communicate directly by the
spoken word to any other individual wherever he may be.

Nor is this linking up of methods of communication restricted
to the surface of the earth. To a limited extent we can com-
municate from distant points above the earth to points beneath
the surface of the earth or of the ocean. To-day we are talking
directly from the high-speed airplanes above the clouds to the
wire systems of the country and ships at sea also can speak from
mid-ocean to land stations of the wire system.

Digitized by

Google

July, 1919] Presentation of Franklin Medal. 115

It is possible, for instance, for the President of the United
States to exercise his functions during residence in Europe which
would have been utterly out of the question a few years ago.
Indeed, the time is not far distant, it is believed, when the Presi-
dent of the United States may address from the White House
practically the entire American people assembled in their respec-
tive localities throughout the country to receive his message by
his own voice.

The radio lighthouse, which shall mark the aerial highways
throughout the land and serve as beacons for the guidance and
location of aircraft on every voyage, is an accomplished fact, and
these will multiply rapidly as each city and town of the country
is brought within the expanding net-work of public and municipal
flying grounds.

These lighthouses have certain advantages over the normal
lighthouses in that their ranges may be much greater, and they
are not invisible in the daytime nor obscured by fog and mist.

Surely no development can surpass in wonder and amazement
the accomplishments of radio telephony and telegraphy and cer-
tain associated subjects now being realized every hour.

We are on the threshold of the inauguration of what is called
the League of Nations and drastic limitations to the enormous
burdens which nations in the past have carried in the creation
and maintenance of military armaments will, it is hoped, be
imposed. The practical execution of the provisions of the League
of Nations from the military, economical, social and diplomatic
standpoints will depend, it is believed, very largely upon the
creation, expansion and maintenance of the most perfect inter-
linked network of inter-communication, literally covering the
land, sea and air. Such a perfect system will be the cheapest
and most certain adjunct to effectively carrying out the provisions
of this League, and will contribute to a better understanding
between nations as will no other agency or instrumentality.

On April 6, 191 7, the Signal Corps of the Regular Army
consisted of 55 officers and 1570 men, and the problem confront-
ing the Corps was how to provide in the shortest possible time
for an installation in Europe as well as in the United States,
which should extend from every factory door and training camp
throughout the United States to the front line trenches in France.

The Signal Corps is a small compact service ranging from
^Yz to 4 per cent, of the Army, which in a peculiar sense serves

Digitized by

Google

1 16 Presentation of Franklin Medal. IJ- F- I-

all branches of the Army as perhaps no other service does. To
illustrate, if at any time prior to the signing of the armistice we
were to subtract from the American Army the Signal Corps in
its entirety for a single hour, the whole military machine would
utterly collapse. This is believed not to be the case to the same
extent for any other equal per cent, of the Army. This merely
means that this small percentage, which may be called the nervous
system of the body of the Army, must be made both in personnel
and materiel as efficient and perfect as possible.

Nothing should be left undone which contributes in any man-
ner to the creating and maintaining of the highest efficiency in
this small percentage of the Army which adds this vital service.

The advance in the science and art of electrical communication
has reached a point where it may be said that the Signal Service
stands to-day as a distinctly technical service second to none in
the Army.

Realizing the utter unpreparedness of this country at the time
we entered the war and having been fortunate enough to have
been in Europe with one of the allied armies covering a period
of two years of the war, I realized that the only hope of an
adequate Signal Service in the shortest possible time was to so
arrange matters that the very best trained men in this country
already engaged in the telephone, telegraph and electrical indus-
tries should be made available forthwith after the outbreak of war.

Our problem was a diflferent one in this country from that of
our Allies where the telegraph and telephone systems are already
in control of the Government.

Realizing the importance of this, sometime in January, 191 7,
as I remember it, prior to the entrance of this country into the
war, I went to New York and had an informal conference with
Mr. Theodore N. Vail, President of the American Telephone and
Telegraph Company; Mr. Newcomb Carlton, President of the
Western Union Telegraph Company, and in particular with my
friend Colonel John J. Carty, in which the general outlines of
the procedure in case we entered the war were talked over and
arranged.

The problem was, How could we pick from these organizations
and other similar utilities the men and equipment needed imme-
diately without crippling that essential service in the United States,
where additional demands would be made in the vast industrial
preparations required at home also?

Digitized by

Google

July, 1919] Presentation of Franklin Medal. 117

Manifestly this could be done only by thorough cooperation
between the Government and the guiding heads of these utilities.

The first move therefore made upon the outbreak of war
was the commissioning of four or five of the leading engineers
and executives in the commercial telephone and telegraph com-
panies of this country and these in turn were charged with the
selection and organization of the trained personnel to be sent
immediately abroad to start the work while the new army could
be trained in this country. These engineers and executives,
instead of being brought to Washington in the early days of the
war, were left directly at their offices, where they had every
facility organized, and they took their orders from the Signal
Office in Washington. With the loyal cooperation of the com-
panies themselves it was possible to send to Europe in the first
months of the war twelve battalions of the best trained men this
country could produce. Each one of these organizations was
composed of officers and men who were already technically trained
and whose conduct and character were vouched for by the organi-
zations from which they came.

In the meantime, of course, the machinery for a large number
of technical schools wus set in motion which later produced the
flow of field and telegraph battalions required for the combatant
troops.

If the Chief Signal Officer had brought this first group men-
tioned above directly to Washington, as would have been the usual
procedure, the time which it would have taken, under the con-
gested conditions necessarily then existing in the War Depart-
ment, to establish these officers and equip them with the office
machinery required, and learn the intricacies of army routine,
would have caused the Signal Corps to lose a great deal of
valuable time in getting the initial start in France.

During the early months of the war, therefore, these officers
in the uniform of their country, installed in their regular offices,
with the full machinery at their disposal, represented for a time
the United States as well as their former employers, and through
the hearty cooperation and loyal support of all hands the Signal
Corps was enabled to get under way with the ablest and most
experienced technical men in the country in the shortest possible
time.

It is difficult to realize to what extent specialization has
reached under the impetus of war in the matter of electrical

Digitized by

Google _

ii8 Presentation of Franklin Medal. [J. F.I.

intercommunication. The mere enumeration of the types of
specialists now required by the Signal Corps is a formidable one.
In addition to regular special troops in the line branches of the
Army this service demands highly trained specialists as follows :

Telephone and telegraph engineers

Traffic and plant experts

Operators both male and female, speaking French, English and German

Installers and maintenance experts

Telephone and telegraph repeater experts

Printing telegraph mechanicians

Traffic supervisors and test-board men

Traffic and wire chiefs

Linemen '

Switchboard repairers and installers

Radio engineers, constructors and operators

Electrical research experts

Meteorologists

Photographers— both still and motion

Pigeon fanciers

Optical experts and field glass repairmen

Instrument makers and repairers

Shop practice experts and oxy-acetylene welders

Production experts

Gasoline and motor transport experts

Motorcyclists

Chauffeurs

Dry and storage battery experts

Storehouse managers

Cable experts and operators

Draftsmen

RESEARCH AND DEVELOPMENT.

In no branch of the military establishment is the need for
continual research more necessary than in the Signal Corps of the
modem army. Scarcely a single piece of technical apparatus that
was regarded as adequate at the beginning of the war is to be
found in the Signal Corps equipment at the time of the signing
of the armistice. Strong research departments were founded
both in France and in the United States and the best men of the
country available were assigned to this work. Many of these
men were taken from universities and colleges and electrical,
chemical, physiological and mechanical specialists were set to work
on both sides of the Atlantic to devise new means of supplementing
the methods of signaling and associated subjects. In engineering
development the demands grew to the proportion of a large indus-

Digitized by

Google

July, ipiQl Presentation of Franklin Medal. 119

trial plant. The entire facilities of the Bureau of Standards were
requisitioned on a large number of special problems and the prin-
cipal personnel of the Weather Bureau were used in the newly
established meteorological service.

It was soon realized that a special laboratory devoted exclu-
sively to development work and entirely independent of the com-
mercial laboratories, such as the Western Electric Company and
the General Electric Company, would be needed, and a special
laboratory fully equipped for radio development was established
at Little Silver, New Jersey, which grew to be one of the largest
in the world. Recently this site has been purchased for the per-
manent use of the Signal Corps and the experience of the present
war has clearly shown the necessity for an institution of this sort
where trained specialists may devote their entire energies to the
new problems constantly arising in the extension of methods of
intercommunication now appearing as never before.

The Science and Research Division of the Signal Corps was
established in Washington and a mere enumeration of the number
of problems which this Division was called upon to investigate
and develop shows to what extent all branches of science were
drawn upon to perfect this service.

TRAINING OF PERSONNEL.

It was not possible to take men from the general draft and
train them as efficient telephone and telegraph men within the
very short time that could be allotted for training, and hundreds
of men assigned directly to Field Signal Battalions from the gen-
eral draft had to be turned back again. The plan eventually
worked out was to obtain 75 per cent, of all Signal Corps per-
sonnel. required, from enlisted men who had completed the course
of instruction laid down by Signal Corps schools. These schools
were established at the principal colleges, universities and tech-
nical schools throughout the country. In addition five large
training camps were established as follows :

Camp S. F. B. Morse
Fort Leavenworth
Camp Alfred Vail
Franklin Cantonment
College Park, Maryland

The curriculum was established for these schools and stan-
dardized for all, which included a thirteen weeks' technical course.

Digitized by

Google

I20 Presentation of Franklin Medal. [J- F. I.

As to the results obtained in the selection and training of
personnel, the following statement was made by Mr. Daniel W.
LaRue, Chief Psychological Examiner, upon the completion of his
work at the Signal Corps Cantonment, Camp Meade, Md. :

" These facts substantiate what has been found in other camps,
that the Signal Corps personnel as a whole have the highest aver-
age intelligence as far as the Army psychological examinations
can determine."

BQUIPMBirT.

The extent of equipment required by a modem army for Signal
Corps purposes is beyond what anyone could have dreamed. As
an example, a single order for a certain kind of insulated wire
was in sufficient amount to extend 14 times around the earth. The
cost of Field Glasses alone exceeded $40,000,000, and Wrist
Watches for Signal Corps operators alone reached a total in
excess of 43,000 watches. Over a million batteries were pro-
duced, and 285,000 Vacuum Tubes for radio amplifiers. Over
100,000 telephones for field use alone were necessary, and over
200,000 pliers for use in line construction work. Over 8000 of
one single type of Radio apparatus was produced and shipped
to France.

The above items constitute but a few of the 267 which are
furnished to various branches of the Army as Unit Equipment.
In addition to these there are over 2000 items for use by the
Special Services and in maintaining communication in the Zone
of Supply.

The above brief outline of the quantities of modern Signal
Equipment required for the conduct of war as it is now under-
stood teaches above all other things one lesson in organization,
which is, that the Signal Corps officer, like a medical officer, must
make the Signal Service his life work. Previous to this war the
Signal Corps of the American Army was organized by detail from
the infantry, artillery, or cavalry, for a period of four years.
Having in mind the services which are rendered to each and all
branches of the army by this small group of specialists, it is clear
that in any plan for reorganization we must first select with great
care the young officers for this service and then give them the
best training to be found in the country for their work, since it is
only by continuous application and study that the Signal Officer
can hope to maintain his efficiency.

The supreme test of the Signal Corps, as of all other branches

Digitized by

Google

July, 1919] Presentation of Franklin Medal. 121

of the Army, is always to be found in the performance of its tasks
under the actiaal tests of battle and in the military areas which
supply and maintain the combatant troops. I cannot better close
these brief observations of the Signal Corps than by quoting a
letter from General Pershing, the Commander-in-Chief, issued
and published to the American Expeditionary Forces under date
of February 19, 1919:

" Now that active operations have ceased, I desire to
congratulate the officers and men of the Signal Corps in
France on their work, which stands out as one of the
great accomplishments of the American Expeditionary
Forces — ^the result of a happy combination of wise plan-
ning and bold execution with the splendid technical quali-
ties of thousands of men from the great commercial
telephone, telegraph and electrical enterprises of Amer-
ica. It is a striking example of the wisdom of placing
highly skilled, technical men in the places where their
experience and skill will count the most.

" Each Army Corps and Division has had its full
quota of Field Signal Battalions which, in spite of
serious losses in battle, accomplished their work, and it
is not too much to say that without their faithful and
brilliant efforts and the communications which they
installed, operated and maintained, the successes of our
armies would not have been achieved.

" While the able -management of the directing per-
sonnel is recognized, it is my desire that all members
of the Signal Corps, who, regardless of long hours and
trying conditions of service, have operated and main-
tained the lines, shall know that their loyalty, faithful-
ness and painstaking care has been known and appreci-
ated. In the name of the American Expeditionary
Forces, I thank them one and all and send to them the
appreciation of their comrades in arms and their Com-
mander-in-Chief."
After the reading of the above paper moving pictures and lan-
tern slides illustrative of A. E. F. Signal Corps activities were
shown under the direction of Captain A. Bliss Albro,and a number
of Signal Corps communication devices, such as T. P. S. sets.
trench and airplane radio sets, etc., were exhibited by Captain
E. F. Pernot.

Vol. 188, No. 1123— 9

Digitized by

Google

122 Current Topics. [J. f. I.

Cements Producing Quick-hardening Concrete. P. H. Bates.
(Proceedings of the American Society for Testing Materials, June
24-27, 1 91 9.) — There have been prepared at the Pittsburgh
branch of the Bureau of Standards certain cements which have
the property of hardening very rapidly. These were made in a
manner no different from that used in making Portland cement,
but their composition differed very materially from the composi-
tion of the latter in that they consisted very largely of lime and
alumina. These calcium aluminates, when they are very high in
alumina, do not have a very marked rapid initial set, but do
harden very quickly and therefore produce high early strengths.
Some of the maximum strengths were 3145 pounds per square
inch for i : 6 gravel concrete, tested in the form of a 6 x 12 inches
cylinder, at the end of twenty-four hours, 6010 pounds per square
inch at the end of seven days, and 8220 pounds per square inch at
the end of one year.

Tests were also made on 6 x 12 inches cylinders in which the
bonding material was " Sorel cement." These cements are produced
by gauging light calcined magnesia with magnesium chloride solu-
tion. The fact that magnesium oxide when mixed with a solution
of magnesium chloride will harden was possibly first known by
Sorel in 1853; from him it has at least taken its more common
name. Such a cement develops in twenty-four hours a strength
approximately equivalent to that developed at the end of seven
days by a similar concrete made with Portland cement. Both of
these cements commend themselves for certain special uses where
a quick-hardening concrete of high strength is required. Neither
would be desirable where subject to the continued action of water.
The Sorel cement alone is on the market at the present time.

Artificial Stone from Mica and Clay. Anon. (The American
Architect, vol. cxv, No. 2268, p. 824, June 11, 1919.) — Mr. Chr.
Ingvaldsen, of Saaheim, Norway, claims to have devised a process
of making a practicable building stone by mixing finely divided
mica with a just sufficient amount of clay or other substance of
similar properties, to form a coherent mass, which is then shaped
into blocks, plates, and other objects of any desired shape and
size. These, it is learned, are then fired at a temperature just
high enough to fuse the mass, the resulting stone having in gen-
eral the same properties as natural mica.

If it be desired to produce stone having greater resistance to
high temperatures the process is modified as follows : Instead of
mica alone, a mixture of equal parts of mica and of crushed
quartz, with just enough clay to act as a binder. The stones
formed from this mixture are fired at a temperature high enough
to secure the fusing of the mica. The result is a homogeneous
mass not only highly refractory to heat, but capable of acting as
an electric insulator.

Digitized by

Google

NOTES FROM THE U. S. BUREAU OF STANDARDS.*

A SIMPLIFICATION OF THE INVERSE-RATE METHOD FOR
THERMAL ANALYSIS.*

By Paul D. Merica.
[abstract.]

The use of stop-watches in taking inverse-rate curves in ther-
mal analysis is described, and it is shown that they may be substi-
tuted for the chronograph, which is often used without sacrificing
accuracy or sensitivity. One operator is able to record the suc-
cessive time intervals for the inverse-rate curve, with their aid,
and no time is subsequently required for the reading and counting
of the chronograph record; the intervals so recorded may be
plotted directly.

STRENGTH AND OTHER PROPERTIES OF WIRE ROPE.*

By J. H. Griffith and J. G. Bragg.

[abstract.]

Nature of Investigation, — Thq paper presents the results of
tests upon 275 wire ropes submitted by American manufacturers
to fulfill the specifications framed by the Isthmian Canal Commis-
sion in 1 91 2. The samples were selected by government inspectors
for acceptance tests of materials to be used at the canal zone.

The rope ranged in diameters from J4 inch to ij^ inches, a
few being of larger diameters up to 3^^ inches. Over half the
specimens were plow and crucible cast steel hoisting rope of 6 and
8 strands, 19 wires each. • The remainder were galvanized steel
guy rope and iron tiller rope of 6 strands, 7 wires and 6 strands,
42 wires, respectively.

The investigation was made primarily to determine the tensile
strengths of the ropes. Much of the experimentation was of a
supplementary character — to determine the general laws of con-
struction of the rope as the basis of the interpretation of their
physical behavior under stress. A comparative analysis was made

* Communicated by the Director.
' Scientific Papers, No. 336.
'Technologic Papers, No. 121.

123

Digitized by

Google

124 U. S. Bureau of Standards Notes. [JF. I-

of the chemical constituents of steels, rope fibres and lubricants
of plow steel ropes submitted by different manufacturers.

Methods of Tests. — The wires at the ends of specimens were
** frayed out" to form a "broom." These were inserted into
moulds, into which molten zinc was poured so as to form conical
sockets for connection to the testing machines. Most of the
tensile tests were made on a 600,000 pound Olsen testing machine,
the ropes of large diameters being tested on the 1,200,000 pound
Emery machine. Stress-strain measurements were made on over
half the specimens. Numerous tests of individual wires were con-
ducted in tensile, bending, and torsion machines. The strengths
of the cables were studied in connection with their modes of con-
struction, the strengths of their component wires, and the types of
fractures which were presented.

Results of Measurements and Tests. — The homologous linear
dimensions of the strands, wires, and fibre cores were found to
vary in direct proportion to the diameters of the ropes. The
diameters of the strands and fibre cores were generally one-third
the diameter of the rope. The mean pitch or lay of the strands
was 7J^ diameters. The mean lay of the wires was 2^ diameters.
The mean diameter of the w^ires was expressed by the equation:

d ^diameter of wires.

I? =: diameter of rope.

A' = number of wires in outer ring of wires of a strand.

C 1.0
K=l 0.8

for hoisting and guy rope,
for extra flexible 8 x 19 hoisting rope.
( .33 for tiller rope.

The aggregate cross sectional areas of the wires was expressed
approximately by the equation :

.41 for 6 X 19 plow steel hoisting rope.
.38 for 6 X 19 cruc. steel hoisting rope.
A=^OD*'.C =^ .38 for 6 X 7 guy rope.

.35 for 8x19 plow steel rope.
.26 for 6 X 42 iron tiller rope.

It was found when the maximum loads determined from ten-
sile tests were platted as functions of the diameters of the ropes
that the curves bounding the lower frontiers of each zone com-
prising the observed values were in close agreement with similar

Digitized by

Google

July, 1919] U. S. Bureau of Standards Notes. 125

curves platted from the minimum strengths stipulated in the speci-
fication of the Isthmian Canal Commission of 1912. These
strengths were also in approximate agreement with the standard
strengths recommended in 1910 by the manufacturers from the
results of their tests of cables similarly classified. The minimum
strengths found from the present investigation are given by the
following empirical equation :

Load = C 75000 D*
Z> = diameter of wire rope in inches.

I .9 to I.I ; mean value about i.o; 6x9 plow steel cables.

J .8 to -95 ; mean value about .9 ; 8 x 19 plow steel and 6 x 19 cruc. cast

] steel cables.

/ .3 to .4 ; mean value ab3ut .35 ; iron tiller and steel guy rope.

The modulus of the rope calculated from stress-strain measure-
ment was found to vary from 3,000,000 to 9,000,000 pounds per
square inch, depending upon the diameter and class of cable.

Plow steel ropes were selected for comparative analyses of the
constituent materials. In the chemical analyses the carbon content
ranged from 64 to 96 per cent, with a mean of about 75 per cent.
The manganese ranged from 25 to 68 per cent., the silicon from 1 1
to 24 per cent. The percentage of phosphorous and sulphur was
relatively low. In certain cases the steel of the filler wires was
softer than the main wires.

The fibres used in making the core of the rope were estimated
as manila, jute, istle, mauritius, manila fibre alone being employed
by certain manufacturers. The preservatives and lubricants on
the cores were composed of wood and vegetable tars, petroleum
products, and fish oil, the practice varying somewhat among the
manufacturers.

There was a reasonable uniformity in the strengths and elonga-
tions of the wires from a particular cable, but a larger variation in
the strengths of the wires from cables of different manufacturers.
This was probably due to the fact that different grades of plow
steel were used by the several manufacturers in meeting the provi-
sions of the specifications.

The cables developed from 72 to 90 per cent, of the aggregate
strengths of the wires. The upper limit of the ratio of the strength
of a rope to the strengths of its wires was found from theoretical
considerations to be 89.2 per cent, for 6x19 plow steel cables.
The differences between the results of the theoretical analvsis and

Digitized by

Google

126 U. S. Bureau of Standards Notes. [J- F.I.

the practical tests were largely attributed to different strengths and
degrees of ductility of the wires, this causing an unequal distribu-
tion of the load among the strands with over-stressing of certain
strands near the point of failure.

NOTES ON THE GRAPHITIZATION OF WHITE CAST IRON
UPON ANNEALING.'

By P. p. Merica and L. F. Gurevich.

[abstract.]

1. The annealing or graphitization ranges of temperatures
were determined for three different compositions used for car
wheels. The temperature of initial precipitation of temper carbon
for six hours of annealing was not noticeably affected by variation
of sulphur content from o.io to 0.20 per cent or by variation of
total carbon content from 3.60 to 3.90 per cent., although the effect
of greater carbon content is to narrow the temperature range
within which graphitization is complete.

2. The temperature of beginning precipitation of temper
carbon was about 830° for the six-hoiu- period of annealing and
about 725 °C. for the forty-eight-hour period. The maximum al-
lowable temperature therefore for the annealing or "pitting'' of
car wheels is about 725 °C.

3. After complete decomposition of all free cementite by an-
nealing at from 1000° to iioo'^C. and cooling at equal rates in a
laboratory electric furnace less grajAite is found in a specimen
cooled from 11 00^ degrees than in one of the same composition
cooled from iooo°C. This indicates that graphite separates di-
rectly from solid solution upon cooling, when its nuclei are already
present.

4. The fact that only 0.20 per cent, of combined carbon was
found in some specimens after annealing at high temperatures and
cooling slowly in the furnace would indicate either that the
graphite eutectoid lies at much lower values of carbon content
than has been previously supposed, that there is at these rates of
cooling a direct precipitation of graphite eutectoid or that there is
a formation of graphite from pearlite at temperatures directly
below that of its formation.

•Technologic Papers, No. 129.

Digitized by

Google

July, iQip] U. S. Bureau of Standards Notes. 127

THE EFFECT OF RATE OF TEMPERATURE CHANGE ON THE
TRANSFORMATIONS IN AN ALLOY STEEL/

By H. Scott.

[abstract.]

Cooling curves taken on an air-hardening steel of the high
speed tool steel type show two critical points on cooling from
920° C, one occurring at about 750° C. accompanied by the pre-
cipitation of the hardening constituent, the carbide, and the other
on fast cooling at about 400 °C., under which condition the car-
bide remains in solution as martensite. On cooling at intermediate
rates both transformations are observed and the constituents,
troostite and martensite, are detected by the microscope. A
transformation is observed on the heating curves taken following
a fast cooling which is manifested by an evolution of heat ending
at about 645 °C., and which represents the precipitation of the
carbide held in solution by previous rapid cooling. The reso-
lution of the carbide under these conditions occurs at a tempera-
ture some 10 to I5°C. higher than after a slow cooling.

The conclusions drawn support the twenty-year-old theory of
Le Qiatelier that martensite is a solid solution of carbide in
alpha iron.

Photographic Evidences of Meter Readings. Anon. (Elec-
trical World, vol. Ixxiii, No. i, p. 36, January 4, 1919.) — The Detroit
Edison Company is using a special camera for taking " load test "
meter readings to establish customers' demand charge. A regu-
lar meter reading camera was rebuilt so that now photographs are
taken showing in the picture not only the meter reading but a
watch dial with the time of reading and also the name and
address of the customer.

The photographic readings have shown their value in a num-
ber of instances where differences of opinion have come up with
regard to the correctness of load curves. For example, in a case
where a customer raised an objection to his bill on the ground
that readings were not taken exactly one hour apart, the produc-
tion of an actual photograph of his meter with the time of taking
shown on the same film satisfied him as to the correctness of the
load test.

* Scientific Papers, No. 335.

Digitized by

Google

128 Current Topics. IJF. l-

Testing Strength of Joint Glues. Anon. (Forest Products
Laboratory, Madison, Wisconsin, Technical Notes No. F-16.) — In
using glues for high-grade joint work, a knowledge of the strength
of the joint is important. A method which is inexpensive, accu-
rate, and suitable for use in a woodworking factory has not yet
been developed. The following method, which is used at the
Forest Products Laboratory, can be employed if a universal tim-
ber testing machine is available.

Two blocks of selected hard maple, about i inch by 2j/^ inches
by 12 inches in size are glued together. After the glue has aged
sufficiently they are cut into shear specimens and these are placed
in a testing machine so that the base of the long half of the
block rests on a metal seat. Pressure is then exerted on the short
half, causing it to slide past the long half at the glued point. The
pressure required to separate the blocks in this way is measured and
the percentage of the area of wood surface torn out by the glue
estimated.

If the failure occurs entirely in the glue, a measure of the
strength of the glue joint is obtained, but if the failure is entirely
or partly in the wood, as frequently happens, the full strength of
the glue is not developed and the test may have to be repeated,
using stronger blocks.

As the same method has been used in securing data on the
strength of wood in shear, when the strength of glue has been
determined, it can be compared with that of any wood whose
average shearing strength is known.

The Forest Products Laboratory has made thousands of tests
on specimens glued with casein and animal glues, and when prop-
erly used, these glues have shown shear values of 2400 pounds or
more per square inch. Few commercial .\merican woods average
more than 2400 pounds per square inch in shearing strength, and
the majority of them average less than 2000 pounds. Many glue
tests have averaged as high as 3000 pounds.

How Much Water Should be Used in C<mcrete? Anox.
{Scientific American, vol. ex, No. 15, p. 365, April 12, 1919.) — The
Emergency Fleet Corporation, in connection with its work on
concrete vessels, has developed an apparatus for testing the
amount of water which should be used in concrete work. An
open metal cylinder is employed resting upon a glass plate. This
serves as a mold which is filled with concrete and smoothed off
level on top. Then the cylinder is raised, leaving the concrete on
the glass plate. If the mixture is very dry, the concrete will main-
tain its cylindrical form, but the wetter the concrete the more it
flows out at the bottom, so that a measure of the consistency of
the mixture can be obtained by measuring the height of the
cylinder or cone of concrete after the metal cylinder has been
withdrawn.

Digitized by

Google

NOTES FROM NELA RESEARCH LABORATORY.*

NOTE ON THE DISTRIBUTION OF ENERGY IN THE VISIBLE
SPECTRUM OP A CYLINDRICAL ACETYLENE FLAME.

By Edw. P. Hyde, W. E. Forsythe and F. E. Cady.

A KNOWLEDGE of the distribution of energy in the visible
spectrum of an acetylene flame has become important within the
last few years through the use of this flame, in cylindrical form,
in investigations of the visibility of radiation. It can be shown
by computation that the data on acetylene published by Coblentz
form a curve in the visible spectrum which will not agree with
that of a black body at any temperature to better than 7 or 8 per
cent. As this would mean that no color-match could be obtained
and as previous experience of the authors had led to the conclusion
that the energy curve of acetylene differed in shape from that of
a black body only in the extreme red, a short investigation was
undertaken to verify this conclusion.

Tungsten lamps whose current color-temperature relation was
carefully determined in this laboratory were sent to the Eastman
Kodak Company and to the Bureau of Standards with the request
that they be compared with the acetylene flame and the current
for color match be found. The results gave an average value of
2360° K. ± 10° K., and neither laboratory reported any difficulty
in obtaining a match in color. However, the Bureau of Stand-
ards reported a difference amounting to about 75° K. between the
flame as given by the Eastman standard burner and that given by
the " Crescent Aero " burner, the latter being higher.

The spectral distribution of the flame was measured by means
of a spectrophotometer and a spectral-pyrometer and the results
gave a curve agreeing within the limits of error with that of a
black body at 2360° K. In the extreme red, beyond 0.70/1 there
was indication of a higher emissivity for the acetylene. A pho-
tographic method gave results corroborating those just mentioned.

A test of the sensibility of the color match method to show
differences in the spectral energy curve, showed that if two spec-
tral curves matched at 0.5/1 and 0.7/1 and differed by as little as

♦ Communicated by the Director.

129

Digitized by

Google

I30 Nela Research ^Laboratory Notes. [J. F.l.

4 per cent, in the middle of the spectrum, the two light sources
could not be made to match in color.

In conclusion, it is recommended that the relative emission
intensities of a cylindrical acetylene flame, at least for that type
represented specifically by the Eastman standard burner and for
the wave-length interval from 0.4^1 to 0.7/*, should be taken as
identical with those of a black body at 2360® K.
Cleveland, Ohio, June, 1919.

American Peat Industry. Anon. (17. S. Geological Survey
Press Bulletin, June, 1919.) — ^The output of crude peat in the United
States in 1918 far exceeded that of any preceding year and the
general increase, which was stimulated by the war, was shared by
practically all branches of the industry. Though extensively used
as fuel in Europe and widely known in the Unit«i States as a poten-
tial source of heat and power, peat has been unable in most parts of
the country to compete with coal and many peat operators have
therefore directed their attention to the utilization of peat in agri-
culture with gratifying results.

Use of Peat in Agriculture. — Peat fertilizer was first marketed
in commercial quantities in 1908, and stock- food peat in 191 2, and
though there is still some prejudice against the use of these prod-
ucts the agricultural branch of the peat industry has been suc-
cessful and the quantity of fertilizer and stock-food peat annually-
produced is increasing. Large quantities of these products were
made in 1918, but the most striking development of the year was the
production of more peat fuel in the New England States than has
been manufactured commercially in the entire United States in all
preceding years. Almost equally striking was the widespread inter-
est manifested in our peat resources which had heretofore been gen-
erally regarded as of doubtful value.

Large quantities of peat or sphagnum moss were produced and
utilized in this country in 1918 for stable litter, packing material,
and surgical dressing, and several hundred thousand acres of peat
soils were used for the growth of both general and truck crops.
The peat litter was produced by the owners of small bogs for
their own use, but the packing material was sold to florists for $25
a ton. According to J. W. Hotson, of the American Red Cross,
more than half a million peat moss pads were prepared in this
country from October, 191 7, to November 11, 1918, by the North-
west and Atlantic divisions of that organization. Most of the moss
was gathered by volunteer labor from bog^s in Washington, Oregon,
and Maine, and the pads were used in American military hospitals,
both at home and abroad.

The quantity of crude peat produced in the United States in
1918 was 151,521 short tons. The total number of plants at which
peat was commercially produced was 25.

Digitized by

Google

NOTES PROM THE RESEARCH LABORATORY,
GENERAL ELECTRIC COMPANY.*

X-RAY CHEMICAL ANALYSIS.
By A. W. Hull.

The method of X-ray crystal analysis developed in the Re-
search Laboratory of the General Electric Company just before
the war is being further developed, as a method of chemical
analysis, which promises to have a very wide and new field of
application in that it gives evidence which other methods do not
supply, namely, the form of chemical combination of each of
the elements present.

The method consists in reducing the substance to be examined
to powder form, placing it in a small glass tube, sending a beam
of monochromatic X-rays through it, and photographing the dif-
fraction pattern produced. The only apparatus required is a
source of voltage, an X-ray tube, and a photographic plate or film.
The amount of material necessary for a determination is one cubic
millimeter. The method is applicable to all chemical elements and
compounds in so far as they are crystalline in form.

The rays from the X-ray tube pass first through a filter, which
absorbs all but a single wave length, then through two slits, which
confine them to a narrow beam (about, i mm. wide) ; then through
the powdered material, which scatters or "reflects" a very small
fraction of them; and thence to the centre of the photographic
film. An exposure of from one to twenty hours is required, ac-
cording to the amount of information desired.

When the film is developed it shows, in addition to the over-
exposed line in the centre, where the direct beam strikes, a series
of other lines on each side of the centre. These lines are caused
by the "reflections" of the X-rays from the tiny crystals in the
powder. Their distance from the centre of the film depends on
the distance between the planes of atoms in the crystal, and there
is one line for every important set of planes in the crystal. It is
evident, therefore, that subsbtances with different crystalline
structures will give entirely different patterns of lines. Substances

* Communicated by the Director.

131

Digitized by

Google

132 General Electric Company Notes. [J. F.I.

of similar chemical nature and therefore similar crystal structure
give similar patterns, but the magnification or spread of the pat-
tern is different for each one, being inversely proportional to the
cube root of the molecular volume. Since no two similar sub-

FlG. I.

stances have exactly the same molecular volume it is easy to dis-
tinguish them, as the difference is cumulative for lines far from
the centre. A further distinguishing mark is the relative intensity
of the different lines which differs greatly even in the most closely

Fig. 2.

related compounds, depending on the relative shapes and sizes of
the atoms in the compound.

A knowledge of the theory of the production of these lines, and
their relation to the crystalline structure of the substance, is not
essential to their use for chemical analysis. All that one needs to
use in a chemical' analysis is the fact that every crystalline sub-
stance gives a pattern ; that the same substance always gives the

Digitized by

Google

July, 1919] General Electric Company Notes. 133

same pattern; that no two different substances give the same
pattern; and that in a mixture of substances each produces
its pattern independently of the others, so that the photograph ob-
tained with a mixture is the super-imposed sum of the photographs
that would be obtained by exposing each of the components sep-
arately for the same length of time. This law applies quanti-
tatively to the intensities of the lines, as well as to their positions,
so that the method is capable of development as a quantitative
analysis.

As illustrations of the general type of photographs obtained
with simple compounds and elements, Fig. i shows a series of
isomorphic alkali halogens, illustrating their similarity of pattern
and their differences in spacing and intensity ; and Fig. 2 gives
a series of dissimilar substances, illustrating their different types
of pattern.

Several actual analyses have already been made which will be
described in detail elsewhere.^ It' has been found very easy to
recognize at a glance each component in a three component mix-
ture and in the case of the simpler salts many more than this could
certainly be identified. Accurate quantitative tests have not yet
been made, but it is anticipated that an accuracy of one per cent,
will be easily obtainable, for components present to the extent of
one per cent, or more of the whole sample.

Waste of Chemicals in Pulping Unbarked Wood by the Sul-
phate Process. Anon. (Forest Products Laboratory, Madison,
Wisconsin, Technical Notes No. €-5.) — In the manufacture of
sulphate and mechanical pulp, all bark must be removed from the
wood before chipping or grinding, since any fragment of bark
finding its way into the pulp makes its appearance as minute
black specks in the finished sheet. For soda or sulphate pulp,
the cleaning is often not so thorough, since the alkaline digestion
tends to destroy the bark. Some mills bark the wood partly or
not at all in the manufacture of sulphate pulp.

To determine the amount of chemical required to pulp un-
barked wood, shipments of unbarked shortleaf yellow pine chips
and of clear bark were tested by the Forest Products Laboratory
of the U. S. Forest Service, at Madison, Wisconsin.

A determination upon a lo-pound sample showed that the un-
barked chips contained approximately 96 per cent, wood and 4 per
cent, bark, on a bone dry basis. Sulphate pulping trials on clear
bark showed that 28.6 pounds of caustic soda and 10.6 pounds of

'/. Am. Chem. Soc. for June or July.

Digitized by

Google

134 Current Topics. [J. F.i.

sodium sulphite were required per loo pounds of bone dry bark.
A yield of 20.9 per cent, of a gelatinous, brownish-black mass,
containing pieces of unreduced bark, was obtained. This ma-
terial could not be screened or washed because it clogged the
screen openings. Hand sheets made of it eave physical indica-
tions of an extremely hydrated stock, the finished sheets being
hard and parchmentized.

The results indicate that in pulping a ton of wood (bone dry),
consisting of q6 per cent, wood and 4 per cent, bark, 22.9 pounds
of caustic soda and 8.5 pounds of sodium sulphite are needed to
reduce the bark. The pulp produced from the bark is useless and,
furthermore, produces a variation in color of the pulp, which makes
it difficult to mantain a uniform shade in the finished paper.

Experimenta With Mixturesi of Acetylene and Coal Gas.

Anon. (London Gas Journal, vol. cxlv, No. 2904, p. 22, January
7, 1919.) — Satisfactory results are said to have attended experiments
which have been made in Switzerland with mixtures of acetylene
and coal gas; the object being the replacement of the usual mixture
of 67 per cent, of oil gas with 33 per cent, of acetylene. It has been
f otmd that a mixture of coal gas and acetylene in equal proportions
gives the same illuminating power as the oil gas combination. The
experiments have further shown that this mixture of gases may be
put imder a pressure of 9 atmospheres, and heated up to 100° C.
without danger.

Gun Powder in Machine Shops. Ano!n. (DuPont News Ser-
vice,) — ^A somewhat novel idea is in successful operation in the
machine shops of the Delaware and Hudson Railroad Company
at Watervliet, N. Y. They are using ordinary black sporting
powder to save the time of mechanics for the following opera-
tions : Blowing nuts and bolts ; breaking up iron and steel to be
scrapped; forcing a locomotive piston when rust or corrosion
binds it ; breaking metal that has become cold in a furnace.

The charge of powder is loaded in steel guns varying in size
from end to end from 5 to 12 inches with other dimensions in pro-
portion, and held by a steel plunger, which is forced out when the
charge is set off. No wad is used. The plunger is milled to a
size to fit the bore of the gun. Some of the gun-barrels are milled
in the shape of an octagonal prism, instead of being cylindrical,
the bore, of course, in all cases being round. The giin after hav-
ing been loaded is jacked up with the mouth within about one
inch of the object to be struck by the plunger and fired. An
average of one ounce of powder is used for each nut or bolt
(sizes in common use on locomotives) that is to be broken off or
loosened. The load, of course, is varied with the work to be done.
By the use of these guns, it is claimed much time and labor can
be saved and that a quick blow can be directed at an object that
is barely reachable otherwise.

Digitized by

Google

NOTES FROM THE U. S. BUREAU OF CHEMISTRY.*

CHEMICAL ANALYSES OF LOGAN BLACKBERRY (LOGAN-
BERRY) JUICES.'

By R S. HollingsheacL

[abstract.]

The Bureau of Chemistry recently completed an investiga-
tion, undertaken to establish methods for the detection of dilution
common in commercial products made from the Logan blackberry,
and to set analytical standards for them. Logan blackberry juice
has become very popuplar as a beverage, and the berry is used also
in making jams, jellies, and soda-fountain sirups. The juice is
naturally so sour that when it is to be used as a beverage it must
be diluted, from 2 to 3 parts of water being the usual proportion,,
and sweetened with sugar, about i part. As a rule, sirups for the
soda-fountain are prepared by adding sugar to the undiluted juices,,
in the proportion of from about i part of juice to i part of sugar
to, roughly, 3 parts of juice to i of sugar.

Many samples of the pure expressed juice and of the commer-
cial product made from berries grown in Washington and Oregon
were analyzed by the Bureau in 19 16, while in 191 7 a large number
of samples made from California berries were examined.

The juices from the fruit grown in Washington and Oregon
were found to differ markedly in composition from those which
came from the California berries. A large variation was also
noted in the composition of juices from fruit g^own in the dif-
ferent parts of these States, due probably to the difference in rain-
fall. Apparently California juices have a somewhat higher ash
content and lower acid content than those from the more northern
States.

It would seem impossible to determine exactly the amount of
water which has been added to commercial Logan blackberry
juices. Its presence can, however, be detected, and the amount
roughly approximated. The following table gives the tentative
limits suggested for the most significant determinations on Logan
blackberry products.

♦ Communicated by the Chief of the Bureau.

^ Department of Agriculture Bulletin 773, issued May ag, 1919.

135

Digitized by

Google

136

U. S. Bureau of Chemistry Notes.

[J. F. I.

Tentative Limits far Logan Blackberry Juices.

Non-sugar solids

Ash

Acids, as citric

Source

Max-
imum

Min-
imum

Max-
imum

Min-
imum

Max-

imum

Min-

imiim

Washington and Oregon

California

Per cent.
3.92
3.74

Per cent.
2.80
3.06

Per cent.

0.43

.63

Per cent.

0.25

•43

Per cent.
2.33
1.96

Per cent.
1.42
I 06

AN AEROBIC. SPORE-FORMING BACILLUS IN CANNED

SALMON.'
By Albert C. Hunter and Charles Thorn.

[abstract.]

Bacteriological examination of 530 cans of salmon, repre-
senting 9 different brands, showed 237 unsterile cans, 224 of
which contained a particular organism of the mesentericus group,
either in pure culture or mixed wath other species. Only 13 of the
cans showed active spoilage.

The organism is an obligate aerobic spore-former, Gram posi-
tive, and motile. It produces a dark-red ring about a centimeter
below the colony in carbohydrate media and causes rapid decom-
position in fish.

No relation exists between the presence of bacteria of this type
and the quality of the food when the can is opened. The fish in
many cans containing the organisms appeared to be perfectly fresh
and sound, while in some sterile cans the fish was obviously
decomposed.

A bacteriological test for sterility in canned food may show
viable organisms without demonstrating spoilage. The purpose
of canning is accomplished if the food is preserved but the finding
of viable organisms calls for close scrutiny both of the material
and of the canning method used.

ZINC IN OYSTERS."
By R. S. Hiltner and H. J. Wichmann.

[abstract.]

In 191 5 notable amounts of zinc in oysters were found almost
simultaneously in two of the laboratories of the Bureau of Chem-
istry, each working independently of the other and on quite dif-

*/. Ind. Eng. Chem., Vol. xi, No. 7 (July, 1919).
•/. BioL Chem., vol. xxxviii, No. 2 (June, 1919).

Digitized by

Google

July, I9I9.J U. S. Bureau of Chemistry Notes. 137

ferent problems. The Bureau, therefore, undertook an investiga-
tion of the occurrence of zinc and also of copper in oysters from
various localities on the Atlantic seaboard. The relation of the
zinc content of the water in which the oysters grew to that of the
oysters, and the ratio of zinc to copper in oysters, were studied also.
The results of this investigation indicated that zinc is univer-
sally present in oysters, at least in those grown in Atlantic waters,
and that it is probably always associated with copper. It was also
evident that no direct relation exists between the zinc content and
the body weight of the oysters, no uniformity in the ratio of zinc
to copper, and no correlation between the zinc content of the
oysters and that of the water in which they grow. The average
zinc content of 60 samples of oysters analyzed was found to be
457 milligrams per kilogram, the values ranging from 26 to 1300.
The quantities of copper found in 29 samples ran from 12 to 362,
with an average of 80 milligrams per kilogram. The greater
amotmts were found in water contaminated by metallurgical and
factory wastes. Vegetation and organic matter dredged up with
the oysters in one locality contained notable quantities of zinc, and
in some instances traces of copper.

COMMERCIAL PRESERVATION OP EGGS BY COLD STORAGE.'

By M. K. Jenkins.

[abstract.]

An extensive investigation on the preservation of eggs by cold
storage was conducted during the seasons of 1914, 1915, and 1916.
The contents of 841 cases were examined ongoing in and again on
coming out of storage. That is, approximately 26,000 eggs were
examined individually, each egg being candled twice. Most of
the eggs used in the observations recorded were purchased in the
Com Belt States of the Middle West, and were shipped east in re-
frigerator cars, being from 3 to 7 days en route. As soon as re-
ceived they were transferred to a commission house equipped with
chill rooms, a candling and a breaking room, all of which were
refrigerated. Here numerous observations were made of the eggs
before being stored and at various intervals during the storage
period.

* U. S. Department of Agriculture Bulletin 775, issued June 3, 1919.
Vol. 188, No. 1 123— 10

Digitized by

Google

138 U. S. Bureau of Chemistry Notes. [JFI.

Candling proved to be a much more accurate method for the
selection of eggs than inspection or clicking.

Freshly laid eggs, with clean whole shells that had not been
wet, showed a negligible loss in bad ^gs, even after they had been
stored 10 or 11 months.

The rate of evaporation of moisture from eggs was remark-
ably uniform during the storage period, and averaged from 3 to 4
ounces per case per month in the storage rooms under observa-
tion. This moisture was condensed on the brine pipes and ab-
sorbed by the air, the case and the fillers. Most of the absorption
of moisture by the egg packages occurred during the first few
months in storage. A gradual rise in the humidity of the cold
storage room was noted with the advance of the season.

Eggs which were. fresh when stored showed, after being held
some time, an increased air space, and often a tinge of yellow in the
white. Although the yolk membrane became slightly weakened,
commercial separation into white and yolk usually was easily ac-
complished, even after eleven months' storage. The percentage
of ammoniacal nitrogen in ^gs increased during storage, the rise
being greatest during the early part of the storage period.

While held commercially in cold storage eggs develop a char-
acteristic " cold storage " taste, which usually can be detected
about the seventh month in storage, and grows stronger the
longer the eggs are held thereafter. This flavor probably is due
to the absorption of the odors from the surroundings, particularly
the strawboard fillers in which the eggs are packed.

Hydroelectric Power for West Coast of Africa. Anon. (^Elec-
trical Review, vol. Ixxiv, No. 24, p. 981, June 14, 1919.) — A hydro-
electric plant is being built by the Bauchi Tin Mines, Northern
Nigeria, which will be used to operate the tin mines. This
hydroelectric development will have an initial capacity of 1500
horse power, which will be transmitted 12 miles to the mines. The
cost of the installation will be in the neighborhood of $400,000. It
is estimated that the cost of energy will be about 1.2 cents per
kilowatt-hour as compared to 5.2 cents for energy generated from
coal or oil. The annual saving which it is estimated will result from
this change is $195,000.

Digitized by

Google

NOTES FROM THE U. S. BUREAU OF MINES.*

MOTOR GASOLINE; PROPERTIES, LABORATORY METHODS
OF TESTING, AND PRACTICAL SPECIFICATIONS."

By E. W. Dean.

Gasoline as bought on the market may be the product of
ordinary refinery distillation, it may be casing-head gasoline
blended with heavy naphtha, or it may be the product of a crack-
ing process. These three may be blended with each other in vary-
ing proportions. The volatility desirable depends on the service
required and on the vaporizing power of the engine. In general,
there should be enough loco-boiling constituents to permit the
ready starting of a cold motor and not enough to make the gasoline
dangerous and subject to high evaporation losses. Within the
capacity of the engine to utilize them efficiently the heavier and
less volatile fractions have a greater horsepower per gallon. Pro-
posed specifications for gasoline are given, analytical methods and
equipment used in connection with them are described.

TRAPS FOR SAVING GAS AT OIL WELLS.*
By W. R Hamilton.

An oil well that does not produce appreciable quantities of
gas along with the oil, especially during its early life, is an excep-
tion. When wells flow freely into the air a serious loss of oil
results. The loss is from two causes : ( i ) The sudden release of
pressure which allows the gas to escape and carry with it quantities
of oil which arc held in suspension; and (2) the evaporation caused
by the spray of oil. The loss from evaporation alone in a wildly
flowing well producing oil of Gushing grade, will probably exceed
25 per cent, during the time of expulsion. This does not cover
losses in handling and storage. The gas is of course wasted. Not
only do the so-called dry gases escape, but they carry away much
of the lighter oil fractions as vapor, so that the escaping gas is
often highly saturated with gasoline, causing a heavy loss.

♦ Communicated by the Director.

* Technical Paper No. 214.
'Technical Paper 209.

Digitized by

Google

I40 U. S. Bureau of Mines Notes. [J. f.i.

Gasoline traps are simple in construction. The mixture of oil
and gas is allowed to flow through a chamber large enough to
reduce the velocity of the mixture to the point where the oil and
gas tend to separate. The gas is drawn off from the oil at the top
of the chamber. The oil is drawn off at a point below the level
of the liquid so that the escape of gas through the discharge
opening is prevented. In this way all the gas is saved and its
gasoline content may be recovered and the evaporation of the oil
is prevented. In addition, the danger of the well catching fire
is greatly reduced. Different designs of traps are described, some
one of which will be suited to the conditions existing in any given
well. The small cost of a trap and the large savings which result
from its use make it desirable that they should be used in all cases.
It would, in fact, be desirable that their use should be made com-
pulsory by State legislation.

LIGNITE: ITS CHARACTERISTICS AND UTILIZATION.*
By S. M. Darling.

One-third of the known coal resources of the United States
consists of lignite, which is little used because it normally contains
35-30 per cent, of water as mined, but loses it by evaporation
on exposure, with the result that it crumbles into fine pieces during
shipment. The freight rate on the contained water is also import-
ant. As a result 2,000,000 tons of bituminous coal, hauled on the
average 1000 miles, is shipped annually into territory tributary
to the North Dakota lignites that could be supplied with lignite
with an average haul of 400 miles ; saving annually the travel for
600 miles of 50,000 coal cars and 1200 engines and train crews.
The same general condition obtains in the territory tributary to
the Texas lignites. Dried lignite may be used on automatic
stokers, pulverized lignite may be used in that form, dried lignite
briquettes may be used in hand-fired furnaces, carbonized lignite
may be used in suction power-gas producers, and carbonized
lignite briquettes may be used for industrial heating. Raw lignite
used in by-product gas producers yields 60,000 to 70,000 cubic feet
of gas of 140 B. T. U. per cubic foot ; 70 to 80 pounds of sulphate of
ammonia, and some tar, of undetermined value. The experi^
ments so far conducted open wide economic and commercial possi-

* Technical Paper 178.

Digitized by

Google

July. I9I9] U. S. Bureau of Mines Notes. 141

bilities, and it is believed that the broader and more thorough
investigation made possible by the recent appropriation of $100,-
000 for investigation by the Bureau of Mines will point the way
to the establishment of carbonizing and briquette plants through-
out the lignite-bearing regions of the country. The present yearly
production of coal amounts to o.oi 7 per cent, of the known minable
coal resources of the country. C. P. Steinmetz is authority for
the statement that the possible hydro-electric power that could be
developed if every drop of water in the whole United States could
be used would not supply an equal amount of power. It is evi-
dent, therefore, that the dficient utilization of our lignite resources
is a problem of the first magnitude.

MINOR NOTES.

T. N, T. — ^An investigation of the hygroscopicity of T. N. T.,
recently completed at the Pittsburgh Station of the Bureau of
Mines, shows that it is no greater than that of an empty crucible
or one filled with powdered glass; that the moisture absorbed
in a saturated atmosphere is merely that due to the usual moisture
deposited on non-hygroscopic substances under these conditions.
The detailed results of this study will soon be published.

Waste Products of Kaolin, — It has been found by the Colum-
bus Station of the Bureau that the waste products from the refin-
ing of kaolins can be used in some cases for the making of high-
grade silica fire-brick. Where the brick are highly colored with
iron, a 2 per cent, solution of CaClg is used and the chlorine liber-
ated removes most of the iron by volatilization. Dolomite brick
were successfully made by mixing 12 per cent, coal tar with dead-
burned dolomite, pressing at 1000 pound per square inch and
burning to cone 20. In order to make brick more resistant to
slaking, dipping in dehydrated tar was found to give the best
results.

Photometer, — The construction of a photometer to measure
the intensity of luminosity of dials or other surfaces covered with
radium luminous material has been completed at the Golden,
Colorado, station.

Geophone. — In a recent test with the geophone at coal mines
in Pennsylvania, pounding with a sledge in the rib of a mine was
detected through a cover of 525 feet.

Volatilisation Plant, — The new volatilization plant at the Salt
Lake City Station of the Bureau consists of a rotary kiln with a

Digitized by

Google

142 U. S. Bureau of Mines XoteSw [J.F.I.

capacity of 300 pounds ore per hour and a Cottrell precipitation
plant with a capacity of 3000 cubic feet of gas per minute. The
kiln has a length of 20 feet and is heated with a hi^-prcssure
burner, burning gas oil of 25° B.,and is driven by an electric motor
so arranged that the speed of rotation may be varied. The Cot-
trell precipitator consists of two imits of twenty 6-inch pipes each.
It is operated by a Thoradson 5 KVa. 80,000-volt precipitator
transformer and a Western Precipitation Company rectifier. The
regulation of the primary voltage of the transformer is obtained
by an auto transformer and a theatre dimmer.

Mine Fires. — At the mine of the Princeton Coal Company,
Indiana, an area which had been sealed off to extinguish a fire
was recovered with the co<^ration of the Bureau engineers, at
the end of April.

Alaska Power Dez'elopment, — A study of the possibilities
of power development in the interior of Alaska has been made by
the Fairbanks Station, which indicates that the present demand
for coal for domestic heating, steaming purposes, and for electric
power for placer and lode mining and domestic use would justify
the erection of a plant to utilize the Nenana lignite. A car-
bonization plant- would furnish the solid fuel required and yield
enough gas to generate part of the power required. The remain-
der would be generated by a steam plant burning carbonized or
dead lignite. To the present time the demand for fuel has been
met with wood, but the growing scarcity and increasing cost of
it make it essential that some other iorm of power supply be made
available, otherwise the mining and other industries of the region
will inevitably suflFer a progressive decline.

Silver Chloride, — ^An investigation of the vapor pressure of
silver chloride is in progress at the Berkley station of the Bureau.
The method is not yet sufficiently standardized to yield thoroughly
reliable results, but the work so far indicates that the vapor pres-
sure of silver chloride is less than 5 mm. at 1000° C. and in the
vicinity of 15 mm. at 1150° C. It is therefore much less volatile
than lead chloride.

Mine Gases. — An extensive series of gas samples were taken
at the recent fire in the Argonaut Mine, California, and it was
found that the systematic analysis of gases from the main venti-
lation shaft served as a reliable index of conditions in the fire zone.

Digitized by

Google

THE FRANKLIN INSTITUTE.

COMMITTEE ON SCIENCE AND THE ARTS.

(Abstract of Proceedings of the Stated Meeting held Wednesday,
June 4. 1919-)

Hall of The Franklin Institute,
Philadelphia, June 4, 1919.
Mr, Benjamin Frankun in the Chair,
The following report was presented for final action :

No. 2729: Simplex Fluid Meter. A quorum not being present, final
action was deferred.

R. B. Owens,
Secretary,

MEMBERSHIP NOTES.

ELECTIONS TO KEMBERSHIP.

(Stated Meeting, Board of Managers, June 11, 1919.)

resident.

Mr. Walter B. Murphy, Manufacturing Manager, The Barrett Company,

Chemical Department, Frank ford, Philadelphia, Pennsylvania.

non-resident.

Dr. £. A. Eckhardt^ Physicist, Bureau of Standards, Washington, District oi

Columbia.
Mr. FRANas P. Fleming, Attorney-at-Law, Heard Building, Jacksonville,
Florida.

CHAirOES OP ADDRESS.

Mr. G. Edward Barnhart, 318 Mills Avenue, Akron, Ohio.

Mr. William E. Bullock, 29 West 39th Street, New York City, New York.

Mr. Thomas L. Burton, Westinghouse Air Brake Company, 165 Broadway,
New York City, New York.

Mr. Edwin M. Chance, 611 Chestnut Street, Philadelphia, Pennsylvania.

^R, Frank H. Clark, 15 Park Row, New York City, New York.

Lieutenant Colonel George S. Crampton, M. C, U. S. A., Office of the Sur-
geon, District of Paris, No. 7, Rue Tilsitt, Paris, France.

Mr. J. H. Granbery, care of Morgan, Harjes & Company, 14 Place Vendome,
Paris, France.

Mr. Wiluam a. Haines, 6445 Wissahickon Avenue, Philadelphia, Pennsyl-
vania..

Mr. H. a. Hornor, Minerva P. O., Essex County, New York.

Miss Emily E. Howson, Glen Moore, Chester County, Pennsylvania.

Mr. Edwin F. Kingsbury, Eastman Kodak Company, Rochester, New York.

Mr. Clinton N. Laird, Canton Christian College, Canton, China.

Dr. Hugo Lieber, 23 East 26th Street, New York City, New York. . y

Mr. J. Milliken, Union Arcade Building, Pittsburgh, Pennsylvania.

143

Digitized by

Google

144 Library Notes. [J-F.I-

Mr. Hugh Rodman, Rodman Chemical Company, Verona, Pennsylvania.
Ms. James G. Vail, Philadelphia Quartz Company, 121 South 3d Street, Phila-
delphia, Pennsylvania.
Mk. Francis Ralston Welch, Devon, Pennsylvania.
Ms. Alan Wood, 3d, Flat Rock, North Carolina.
Major Arthur W. Yale. 1947 Lin wood Avenue, San Dtego, California.

NECROLOGY.

Mr. C W. Allen, 523 Oley Street, Reading, Pennsylvania.

Mr. Charles O. Baird, 207 Croeer Building, Philadelphia, Pennsylvania.

Miss Harriet Blanchard, 151 1 Walnut Street, Philadelphia, Pennsylvania.

LIBRARY NOTES.

PURCHASES.

Carnegie, David, and Gladwyx, S. C. — Liquid Steel, Its Manufacture and

Cost 1918.
Chemical Society of London. — Annual Reports on the Progress of Chemistry.

Vol. 15. 1918.
Crowther, J. A. — Life and Discoveries of Michael Faraday. 191 8.
Etch ELLS, £. F. — Mnemonic Notation for Engineering Formulae. 1918.
Findlay, Alexander. — Osmotic Pressure. 1919.

Harger, W. G., and Bonney, E. A. — Handbook for Highway Engineers. 1919L
KiNNicuTT, L. P., Winslow, C. E. A., and Prait, R. W.— Sewage Disposal.

1919.
Lewis, W. C. McC— A System of Physical Chemistry. 3 vols. 1918.
Macrobert, T. M. — Functions of a Complex Variable. 191 7.
Miller, B. L., and Singew.\ld, J. T. — Mineral Deposits of South America.

1919.
Ross, Joseph. — Waterproofing Engineering. 1919.
Washington, H. S. — Manual of the Chemical Analysis of Rocks. 191 9.

GIFTS.

Academia das Sciencias de Lisboa, Boletim da Segunda Qasse, Vol. xi, Fasiculo
Nos. I and 2; Historia e Memorias da Academia, Novo Serie, Tomo xii,
part ii; Journal de Sciencias Matematicas, Fisicas e Xaturais, Terceira
Serie, Tomo i, Numeros 3 and 4 ; Depois do Terremoto, por. G. de Matos
Sequeira, Vol. ii; Relacao da Embaixada a Franca em 1641, por Joao
Franco Barreto; Sessao Publica, 2 de Junho de 1918; Arsenicais e
Sifilis Critica do Tratamento Abortivo, por Thomax de Mello Breyncr;
Lord Byron's Childe Harold's Pilgrimages to Portugal critically examined
by D. G. Dalgado. Lisboa and Coimbra, 1917-1919. (From the Academy.)

Alberger Pump and Condenser Company, Bulletin No. 29. New York, N. Y.,
no date. From the Company.)

American Society of Mechanical Engineers, Year Book, 1919. New York,
N. Y., 1 919. (From the Society.)

Digitized by

Google

July, I9I9] Library Notes. 143

American Steam Conveyor Corporation, Catalog on Reducing Ash Disposal
Costs. New York, N. Y., 1919. (From the Corporation.)

Amherst College, Catalog 191 8-1 91 9, and Report of the President to the Trus-
tees. Amherst, Mass., 1918. (From the College.)

Archdale, James & Son, Catalog of Drilling Machines. Birmingham, England,
1918. (From the Company.)

Association Fran^aise Pour TAvancement des Sciences, Conferences, 19 17-

1918. Paris, 1918. (From the Association.)

Badenhausen Company, Bulletin No. loi: Philadelphia, Pa., 1919. (From the
Company.)

Bangor Public Library, Annual Report 1918. Bangor, Pa., 1919. (From the
Library.)

Bettcher Stamping and Manufacturing Company, Catalog of Flat Split Keys.
Cleveland, O., no date. (From the Company.)

Biehl Iron Works, Inc., Catalog No. 8. Reading, Pa., 191 9. (From the
Company.)

Boston and Maine Railroad, Annual Report 1918. Boston, Mass., 1919. (From
the Company.)

Brady, James A., Foundry Company, Bulletin No. 3. Chicago, 111., 1919.
(From the Company.)

Bridgeport Safety Emery Wheel Company, Inc.. Catalog C, Grinding Wheels
and Machinery. Bridgeport, Conn., no date. (From the Company.)

Buckeye Twist Drill Company, Catalog No. 6. Alliance, O., no date. (From
the Company.)

Budd Grate Company, Catalog on Boiler Furnace Operation. Philadelphia,
Pa., no date. (From the Company.)

Buffalo, Rochester and Pittsburgh Railway Company, Thirty-fourth Annua!
Report, for the year ending 1918. Rochester, no date. (From the Com-
pany.)

California Board of State Harbor Commissioners, Biennial Report for the
Year Commencing July i, 1916, and Ending June 30, 1918. San Fran-
cisco, 1919. (From the Board.)

Camden Forge Company, Catalog of Forgings. Camden, N. J., 1919. (From
the Company.)

Canada Department of Trade and Commerce, Report Relating to Mail Sub-
sidies and Steamship Subventions, 1918. Ottawa, 1919. (From the Depart-
ment.)

Catholic University of America, Year Book, 1919-1920. Washington, D. C,

1919. (From the University.)

Chain Belt Company, Catalogs Nos. 95, loi to 105. Milwaukee, Wis., 1919.
(From the Company.)

Champion Engineering Company, Bulletin No. 106. Kenton, O. (From the
Company.)

Columbian Bronze Corporation, Book : Propellers in a Nut Shell. New York,
N. Y., 1919. (From the Corporation.)

Concord, N. H., Board of Water Commissioners, Annual Report, 1918. Con-
cord, 1 919. (From the Board.)

Cutler-Hammer Manufacturing Company, Catalog on C-H Wiring Devices.
Milwaukee, Wis., 1918. (From the Company.)

Digitized by

Google

146 Library Notes. [JF, I-

Dartmouth College, Catalog, 1918-1919. Hanover, N. H., 1918. (From tho

College.)
Defender Automatic Regulator Company, Catalog No. 11. St. Louis, Mo.,

1918. (From the Company.)

Denison University, Annual Catalog, 1918-1919. Granville, O., 1919. (From

the University.)
Direct Separator Company, Catalog No. 19. Syracuse, N. Y., no date. (From

the Company.)
Dubilier Condenser Company, Inc., A Record of the Invention, Development

and Uses of the Dubilier Mica Condenser. New York, 1919. (From the

Company.)
Duntley-Dayton Company, Bulletin No. loi. Philadelphia, Pa., 1919. (From

the Company.)
Electric Hoist Manufacturers' Association: The Strong Arm of Industry.

New York, N. Y., 1919. (From the Association.)
Electric Machinery Company, Bulletin No. 501. Minneapolis, Minn., no date.

(From the Company.)
Electric Tachometer Company, Bulletin No. iii. Philadelphia, Pa., no date.

(From the Company.)
Flory, S., Manufacturing Company, Catalog No. 26. Bangor, Pa., 1919. (From

the Company.)
Gold Car Heating and Lighting Company, Catalogs of Heating and Ventilating

Apparatus for Railway Cars. New York, N. Y., no date. (From the

Company.)
Grand Trunk Railway Company of Canada, Report of the Directors and

Statements of Accounts, 1918. Montreal, Canada, 1919. (From the

Company.)
Grafton and Knight Manufacturing Company, Catalog No. 7. Worcester.

Mass., 1919. (From the Company.)
Green Engineering Company, Catalog : The Green Book. East (Chicago, Ind.,

1919. (From the Company.)

Green Fuel Economizer Company, Bulletin No. 151. Beacon, N. Y., 1919.
(From the Company.)

Guaranty Trust Company, Publications : How Business with Foreign Coun-
tries is Financed; Trading with Cliina; Canada Economic Position and
Plans for Development. New York, N. Y., 1919. (From the Company.)

Haverford College, Catalogs 1917-1918 and 1918- 1919. Haverford, Pa., 1919.
(From the College.)

Hollands Manufacturing Company, Catalog No. 24. Erie, Pa., no date. (From
the Company.)

Illinois Steel Company, Catalog of Track Materials. Chicago, 111., 1919.
(From the Company.)

Ingersoll-Rand Company, Bulletins of Air Compressors, Vacuum Pumps,
Steam Engines, etc. New York, N. Y., 1918-1919. (From the Company.)

Jeffrey Manufacturing Company, Catalog No. 210. Columbus, O., 1919. (From
the Company.)

Jointless Fire Brick Company, Catalog of Jointless Fire Brick. Chicago. III.,
1919. (From the Company.)

Digitized by

Google

July, igip] Library Notes. 147

Keller Pneumatic Tool Company, Catalog. Chicago, 111., no date. (From the

Company.)
Koehring Machine Company, Blue Print Suggestions on Haulage; Loading

Stations and Mixer Equipment for Road Work. Milwaukee, Wis., igig.

(From the Company.)
Landis Machine Company, Catalog No. 25. Waynesboro, Pa., 1919. (From

the Company.)
Lawrence Pump and Engine Company, Catalog " C." Lawrence, Mass., no

date. (From the Company.)
Leland Stanford Junior University, Annual Report of the President Stan-
ford University, California, 1918. (From the University.)
Lincoln Twist Drill Company, Catalogs No. 10 and loC. Taunton, Mass., 1918.

(From the Company.)
Locomotive Superheater Company, Bulletin No. T I. New York, N. Y., 1919.

(From the Company.)
Long and Allstatter Company, Catalog of McCHave Grates and Argand Blow-
ers. Scranton, Pa., 1916. (From the Company.)
Maple Flooring Manufacturers' Association, Catalog. Chicago, 111., 1919.

(From the Association.)
Mill Corporation, Catalog No. G-i : Laboratory Glassware. Rochester, N. Y.,

1919. (From the Corporation.)
Minnesota Railroad and Warehouse Commission, Annual Report, 19 18. St.

Paul, Minn., 1918. (From the Commission.)
Moore and White Company, Catalog of Friction Clutches. Philadelphia, Pa.,

1915. (From the Company.)
Nash Engineering Company, Bulletins Nos. 7 and 8. South Norwalk, Conn.,

1918. (From the Company.)
National Transit Pump and Machine Company, Bulletins and Special Bulletin.

Oil City, Pa., 1919. (From the Company.)
New Bedford Board of Health, Annual Report for the Year 1918. New Bed-
ford, Mass., 1919. (From the Board.)
New York State Engineer and Surveyor, Annual Report, and Supplement, 191 7.

Albany, N. Y., 1918. (From the State Engineer and Surveyor.)
Norwalk Iron Works Company, Catalog on Air and Gas Compressors. South

Norwalk, Conn., no date. (From the Company.)
Ohio (Ecological 'Survey, Bulletin No. 21. Columbus, O., 1918. (From the

Survey.)
Page Steel and Wire Company, Booklet on Armco Iron Rods and Wire for

Oxy- Acetylene and Electric Welding. New York, N. Y., 1919. (From

the Company.)
Pacific Tank and Pipe Company, Catalog on Mining Tanks. San Francisco,

Calif., no date. (From the Company.)
Packard Motor Car Company, Catalog of the Packard Liberty Motor. De-
troit, Mich., 1919. (From the Company.)
Pennsylvania Railroad Company, Record of the Transportation Lines, 1918.

Philadelphia, Pa., 1919. (From the Company.)
Pittsburgh Filter and Engineering Company, Bulletin O.E. 20. Kansas City,

Mo., 1919. (From the Company.)

Digitized by

Google ^

148 Library Notes. [J. F.I.

Potter, S. A., Tool and Machine Works, Catolog No. 9. New York, N. Y.,

1 919. (From the Company.)
Rockwell, W. S., Company, Bulletin No. 39. New York, N. Y., 1919. (From

the Company.)
Rose Polytechnic Institute, Bulletin 1918-1919. Terrc Haute, Ind., igiQ-

(From the Institute.)
Schieren, Charles A., Company, Catalog: The Story of Schieren Beltings.

New York, N. Y., 1919. (From the Company.)
Sheffield Machine and Tool Company, Sheffield Tools and Products. Dayton,

O., 191 9. (From the Company.)
S. K. F. Ball Bearing Company, Engineers' Ball Bearing Handbook ; and book-
let: The Present Day Application of Ball Bearings. Hartford, Cona,

1 91 8. (From the Company.)
Smithsonian Institution, Annual Report of the U. S. National Museum, 1918.

Washington, D. C. (From the Institution.)
Springfield, Mass., Board of Water Commissioners, Annual Report, 1918.

Springfield, 1919. (From the Board.)
Standard Spiral Pipe Works, Catalog No. 7. (Chicago, 111., no date. (From

the Company.)
Steere Engineering Company, Bulletins Nos. 34, 35 and Z7' Detroit, Mich.

(From the Company.)
Sturtevant, B. F., Company, Catalogs Nos. 255 and 256. Boston, Mass., 1919.

(From the Company.)
Tasmania Department of Mines, Geological Survey, Bulletin No. 28. Hobart,

19 18. (From the Department.)

Terry, Edward F., Manufacturing Company, Catalog of Derricks and Cranes.
New York, N. Y., no date. (From the Company.)

Thermoid Rubber Company, Booklet: New Principles in Tire Making.
Trenton, N. J., 1918. (From the Company.)

Tinus Olsen Testing Machine Company, C^ttalog No. 10, Part A. Philadel-
phia, Pa., 191 9. (From the Company.)

Tokyo Imperial University, Calendar, 1917-1918. Tokyo, Japan, no date.
(From the University.)

University of Denver, Year Book. Denver, Col., 1919. (From the University.)

University of Florida, Catalog, 1918-1919; Announcements, 1919-1920. Gaines-
ville, Fla., 1919. (From the University.)

University of Nevada, Biennial Report of the Regents, 1917-1918. Reno, Nev.,

1919. (From the University.)

University of Rochester, Annual Catalog, 1918-1919. Rochester, N. Y., 19191

(From the University.)
University of the State of New York, Library Report, 1917. Albany, N. Y.,

1 918. (From the University.)
Ursinus College, Bulletin, 1918-1919, First Quarter. Collegeville, Pa., 1919^

(From the College.)
Uruguay Anuario Estadistico, Ano 1916, Libro xxvi. Montevideo, 1918. (From

the Director (^neral de Estadistica.)
Washington University, Annual Catalog, 1918. St. Louis, Mo., 1918. (From

the University.)

Digitized by

Google

July, 1919.]

Correspondence.

149

Wellman- Sea ver- Morgan Company, Bulletins, Circulars and Catalogs on Hy-
draulic Turbines, Ore and Coal Handling Machinery, and Buckets. Cleve-
land, O., no date. (From the Company.)

Wheeler Condenser and Engineering Company, Bulletin No. 113. Carteret,
N. J., 1919. (From the Company.)

Winfield Electric Welding Company, Catalog of Electric Welding. Warren,
O., 191 7. (From the Company.)

Winter Brothers Company, Catalog No. 13. Wrentham, Mass., 1918. (From
the Company.)

Yale and Towne Manufacturing Company, Semi-Centennial Souvenir. New
York, N. Y., 1918. (From the Company.)

CORRESPONDENCE.

Cable Address "Edison, New York"

From the Laboratory of Thomas A. Edison.

Orange, N. J. April 19, 1919.
Mr. R. B. Owens J Secretary,
The Franklin Institute,
Philadelphia, Penna.

Dear Sir:

I thank you for your letter of April 17th, and wish to express my sincere
appreciation of the honour conferred upon me by The Franklin Institute
in electing me an Honorary Member of the Institute.

Yours very truly,
(Signed) Thos. A. Edison.
A/6969.

War Department
Office of the Chief Signal Officer

Washington, April 23, 1919.
Major R. B. Owens,

Secretary, The Franklin Institute,
Philadelphia, Pa.
Sir:

I have the honour to acknowledge receipt of your communication of April
17, 1919, informing me that at a Stated Meeting of the Institute held on
the evening of Wednesday, April 16, 1919, I was unanimously elected an
Honorary Member of The Franklin Institute.

I beg to express to the Institute, through you, my sincere appreciation of
its action; in thus electing me an Honorary Member of the oldest scientific
institution in America, one which has through all the years exerted a powerful
influence in the advancement of Science and the Mechanic Arts.

Faithfully yours,
(Signed) George O. Squier.

Major General
Chief Signal Officer of the Army.
Vol. 188, No. 1123 — 11

Digitized by

Google

150 Correspondence. [J- F. I-

WOLCX)TT GiBBS MEMORIAL LABORATORY, HARVARD UNIVERSITY.

Cambridge, Massachusetts, U. S. A., April 24, 1919.

Theodore William Richards, Director.

Dr. R. B, Owens,
Secretary,

The Franklin Institute of Pennsylvania,

Sir:

Your letter of April 17th honours me very greatly. I beg that you will
communicate to the Members of the Institute my heartfelt appreciation of the
high distinction conferred upon me by election to honorary membership.
It is an especial pleasure and satisfaction that the eminent men of my native
State and City should thus welcome me to their fellowship ; and I shall always
be proud indeed to have my name entered on the rolls of the famous Institute.
I beg to remain, with assurances of highest regard

Respectfully yours.
(Signed) Theodore W. Richards.

Henry C. Frick Educational Commission.
1954 Perrysville Avenue.

John A. Brashear. President.

Pittsburgh, Pa., May 16, 1919.

My Dear Dr. Owens.

You don't know how proud I am of the beautiful diploma of Honorary
Membership of The Franklin Institute. There are eleven diplomas hanging
on the walls of my work room and all so nice and fully appreciated, but the
Franklin is the prettiest of all.

Then an old fellow like me prizes the names on his diplomas — especially
if they happen to be his friends — and all the names are friends of Uncle John.
I confess that I am in love with this diploma and the honor you have conferred
upon me. The good Lord knows the element of self conceit has never
tainted thfe life of your friend — but when I unrolled the diploraa^or rather
had my granddaughter do it for me, I felt just a pardonable pride I So don't
scold me for this little weakness, for though nearly 79, I am not in my dotage
yet. A fellow working 12 to 14 hours a day trying to send a little sunlight out
into the world to make or help make the shadowed pathways of his fellow
travellers a little brighter should not be accused of dotage, should he?

How I would love to be with you on the 21st. Sir James Dewar has
been a personal friend for 27 years and General Squier a man for whom we
have done some of our best work. I fear I cannot get away.

Thanking you dear Dr. Owens and all your colleagues, I am,

Cordially yours.
(Signed) John A. Brashear,

Digitized by

Google

July, 1919] Correspondence i 5 1

Prof. Dr. H. Kamerlingh Onnes.

Leiden, 24 May, 1919.

HUIZE TER WeTERING

Haacweg.
Sir:

I beg to express my sincere gratitude for the honour The Franklin
Institute has bestowed on me by electing me unanimously as an Honorary
Member. The appreciation in this way of my work by The Franklin Institute
who did me the honour to award one of the first Franklin Medals to me,
makes a deep impression on me. I cannot thank The Franklin Institute
enough for the continued encouragement given to me, but I can assure
The Franklin Institute that this encouragement is of the greatest value for
me now I am restarting my researches which have suffered very much from
the general circumstances as well as from a long illness.

I am respectfully,
(Signed) H. Kamerlingh Onnes.
Dr. R. B. Owens, Secretary of The Franklin Institute of the State of Penn-
sylvania, Philadelphia,

31 Via Garibaldi, Gianicolo,
R. B. Oweni, Esq., Rome, May 30th, 191 9.

Secretary of

The Franklin Institute,
Philadelphia, Pa.
Sir,

Having been away from Italy for some time I have only just received
your letter of April 17 in which you inform me that at a Stated Meeting of
the Institute held on April 16 of this year I was elected Honorary Member.

I take great pleasure in accepting this Honorary Membership of The
Franklin Institute, and shall feel obliged if you will convey to the Governors
of the Institute my deep appreciation of the honor which they have conferred
upon me.

I am.

Respectfully,

(Signed) G. Marconi.

Haarlem, June 8, 1919.
Gentlemen :

Allow me to express my most hearty thanks for the honour you have be-
stowed upon me by electing me an honorary member. I appreciate very much
this new token of the good will with which you have judged my work, and I
consider the membership of your celebrated and time-honoured Institute as
one of the very best rewards that can be given to a scientific man.
With high regards, I have the honour to be, gentlemen.

Your obedient servant.
To THE Members of (Signed) H. A. Lorentz.

The Franklin Institute.

Digitized by

Google —

152 Publications Received. [J. f. l-

PUBLICATIONS RECEIVED.

The Blind, Their Condition and the Work Being Done for Them in the
United States, by Harry Best, Ph.D. 763 pages, 121110. New York. The Mac-
millan Company, 19 19. Price, $4.

U. S. War Department, Annual Reports 1918: 3 vols., illustrations, plates,
maps, diagrams, 8vo. Washington, Government Printing Office, 1919.

U. S. Bureau of Standards: Circular No. 76. Aluminum and Its Light
Alloys. 120 pages, illustrations, 8vo. Washington, Government Printing
Office. Price, 20 cents.

U. S. Coast and Geodetic Survey: Terrestrial Magnetism. Results of
Magnetic Observations Made by the United States Coast and Geodetic Survey
in 1918, by Daniel L. Hazard, Chief, Division of Terrestrial Magnetism. 32
pages, 8vo. Washington, Government Printing Office, 1919.

A Proposed " Poison-Gas." — The signing of the armistice
brought suddenly to a close several terrible methods of offense that
were just about ready to be employed by the allied and associated
powers. These methods have been more or less made known to
the public, and among them is an asphyxiating gas which promised
to be a valuable one for war purposes, and for which American
chemists had just about succeeded in perfecting the procedure for
mass manufacture when hostilities were suspended. The account
of the method of manufacture was given a short time ago in the
Journal of Industrial and Engineering Cltemistry. The substance is
methyldichlorarsin, CHgAsClj. The process of manufacture is
quite elaborate, and, as far as the experiments went, the cost of
the pure product was about $2.50 per pound. The operation did not
reach the extended development that was attained by mustard gas
or phosgene, but was still within what was termed the " Small-scale
Manufacturing Section of the C. W. S.," when Messrs. Uhlinger,
Clapp and Cook, who furnish the account from which this note is
quoted, were released from duty in the matter.

The properties of the substance are not given, but from its close
relation to the kakodyl series it is not difficult to guess at its general
nature as an asphyxiator. H. L.

Coal Production in Germany. Anon. (Power, vol. xlix, No.
25, p. 998, June 24, 1919.) — The German War Commissary states
that Germany's coal production is decreasing in all districts, because
the pay is no longer based on the work done but has a minimum of
16 to 18 marks ($3.81 to $4.28, at normal exchange) per day. The
present coal production in the Ruhr district is 9000 to 10,000 tons
per day, compared with 34,000 tons in peace times and 24,000 tons
during the war. In upper Silesia the daily output has been reduced
to 2000 carloads, compared with 14,000 in peace times and ti.ooo
during the war.

Digitized by

Google

CURRENT TOPICS.

IMapping from the Air. Anon. (U. S. Geological Survey Press

^a/letin. No. 410, June, 1919.) — Requests made to the United

States Geological Survey, Department of the Interior, for infor-

niation concerning the possibilities of photographic surveying

from airplanes or other aircraft have recently become so numerous

"lat it is deemed necessary to issue a statement on this subject.

^3r ti^wo years the United States Geological Survey, which pre-

fh^^^ and publishes more maps than any other organization in

ne A;vorld, has devoted much time and labor to the study of prob-

^rris to be solved in photo-aerial surveying. The camera has

ori^ been used in surveys on the ground, and the Geological

of^^^^^^y ^^s been making studies to determine the best methods

^^^^'^^ing it in aerial work. Before the war the panoramic camera

an,-? ^^mployed by the Geological Survey for mapping in Alaska,

g;;^-;^ \t: has been widely used for photographic surveying in Canada

^/i :^^ ^ ^ Europe. Aerial photographic surveying involves no new

^^^^ ^^iples, yet it differs essentially from photographic surveying

^^*^^e ground, for the line of view from a camera in a balloon or

'^et 'airplane is vertical, not horizontal. A complete statement of

the Geological Survey's investigations in photographic mapping

from the air will later be prepared for publication.

The principal object in an aerial survey is to obtain on a
horizontal plate or film a picture of the area below the camera. If
the area is itself a plane the picture of it taken from an airplane
on such a plate is a true map, but no apparatus has yet been
devised that will maintain the plate in a truly horizontal position
when the airplane is in motion ; and as the earth's surface is almost
nowhere plane the photog^raph must be corrected to obtain a map
free from distortion. The nearest approach to an aerial map so
^ar made is the so-called " mosaic map," which is really not a
"'^p at all but merely a patchwork of photographs. The pic-
tures composing such a mosaic show distortions, due partly to
f^e deviation of the plate from the horizontal position and partly
^u ^^^^^^ 5" *h^ surface photog^raphed, and these distortions render
the picture useless for accurate map construction. Distorted
p/iotogTaphs of an area that has been previously mapped can be
'^ <lown over a network of points whose positions are known,
^nd by distributing the errors due to distortion a mosaic may be
<^onstrvicted that will present a good appearance. For correcting
^"^ revising older maps by the addition of culture, timber areas,
"^}^ roads, and similar features, such mosaics have a distinct
value. |)ut they are worth little as material for use in construct-
^"? '^eAvmaps.

153

Digitized by

Google

154 Current Topics. [JF. I-

It may be said that photographic mapping from aircraft is
entirely practicable but that it has not yet been brought to the
point where it can supersede ground surveying. The science of
cartography will no doubt be greatly advanced when the aerial
method is perfected, but fundamental problems remain to be
solved, and this fact should be recognized and all possible energy
should be devoted to the solution of those problems. It is hoped
that solutions of the essential problems in photo-aerial surveying
will soon be obtained, and that this method will be put to prac-
tical use in map-making.

New Chemical Journals and a New Method in Chemical
Journalism. H. Leffmann. (The Catalyst, vol. iv, No. 5, May,
1919.) — Early in the year 1918 the Swiss Chemical Society decided
to begin the issue of a journal to appear from six to eight times
a year, and contain brief notes and formal memoirs in the three
languages (French, Italian and German) used in the country. By
this means the Society hopes to give to the world a synopsis of
the labors of Swiss chemists. The preface of the first number is
dated at Geneva, April 25, 1918. The rivalry of the three lan-
guages, of course, increased in bitterness by the events of the last
four years, has been deftly avoided by the founders of the journal
by putting the title in Latin, Helvetica Ch&mica Acta, The first
number is standard octavo size, containing ninety-five pages of
original matter, well printed on good paper. The prospectus is
given in the three languages, but the preface is in French. Of
the seven contributions, four are in German and three in French.
They cover both pure and applied chemistry. Among the latter
is a notable one on the occurrence of hydrogen selenid in rain-
water and melted snow. Several issues have appeared, and the
amount and quality of the contents have maintained the standard
of the initial number.

The other newcomer is from France. It is the official journal
of the newly-formed French society of industrial chemistry. The
first number of the journal (Chimie et Industrie) is dated June i^
1918, and it has been continued since as a monthly. It contains
about one hundred pages well printed on good paper of about the
area of the J. I. E. C. The matter of the journal is of very good
quality, and covers the usual variety of original papers and ab-
stracts of current literature, but a special feature deserves some
notice. Each number contains a section on " Economic Organ-
ization," in which questions of education, teaching, professional
apprenticeship, industrial hygiene, protection of childhood, anti-
alcoholic and antituberculosis crusades can be treated with a
breadth of view and interest that they deserve. This indicates
a broader scope than is usual in chemical journals, and affords
an inkling of the deep impression that socialism has made upon
the educated classes of France, especially in professional circles.

Digitized by

Google

Juiy,i9i9.] Current Topics. 155

Science and Industry. (Machinery, London, vol. xiv, No. 350,
p. 321, June 12, 1919.) — A new viewpoint manifests itself in the
interminable controversy upon the application of science to industr>%
with which is bound up the place that theoretical training must
take in engineering education. The whole history of the conflict
of opinion among educationalists and industrialists is that the former
has continually and dogmatically laid it down that the practical
man in the past has had little understanding of the value of science
and has therefore failed to appreciate the place which it should play
in industrial life. Generally speaking, the so-called practical man has
accepted the doctrine that science and theoretical training must take
a more prominent place, and he has left it largely to the educationalist
to define that place. A change, however, appears to be coming over
the attitude of the practical, or, shall we say, the business man, in this
respect. The point of view is that whilst professors and teachers wish
the industrial employer to have a greater faith in science, have they
themselves as much enthusiasm and faith — and, be it added, knowl-
edge of practical conditions — in industry ? In other words, have the
teachers the practical knowledge which enables them to teach science
in such a way that it can be applied to the best advantage in industry ?
Hitherto our universities and technical colleges have placed rather
too narrow a limit upon the meaning of science ; there is something
more than a science of things which needs to be taught those who are
to take the leading places in industry, and it has been well pointed out
that there are such things as the science of management — the appli-
cation of psychology in management — the training of staff and the
direction of salesmanship to which at present our universities and
colleges are paying very little attention. We believe that the only
organized effort of this nature is being made at the Manchester Uni-
versity, but this aspect of the application of science in education and
in industry must play a larger part in the minds of those from whom
we are expected to take the law as regards education. That can only
come about through the medium of a greater practical knowledge on
the part of the teachers. This, perhaps, raises important questions
as to whether the remuneration offered to those who are expected
to teach our young men is sufficient to attract the right kind of men.
Anyway, experience has shown that the average man engaged in
industry has not the time, and often not the ability, to undertake
teaching. Therefore we shall have to continue to rely mainly upon
theoretically trained men for the purpose, but steps must be taken
to keep such men in close contact with the needs of industry before
we can expect our university and college curricula to fit those needs.

Digitized by

Google

156 Current Topics. [J.F. I.

Moving Pictures in Science. {Engineering News-Record, vol.
Ixxxii, No. 26, p. 1239, June 26, 1919.) — Motion-picture houses for
some time have been showing pictures of what they call the " analysis
of motion," in which well-known actions, such as figure skating,
sprinting and baseball pitching, are reproduced on the screen at
one-eighth the actual speed of the performer. Every element of
motion in these pictures stands out with snapshot clearness. Grace
hitherto unsuspected is revealed, and the methods by which results
are achieved are understood as never before. This latter phase
has decidedly an engineering application in the development of motion
study and its consequent readjustment of production pethods. No
false or unnecessary movement can escape detection, but at the
same time tlie sense of motion, lacking in a series of snapshots, is
always present. An analogy may be found in the system used by
Nathan C. Johnson in studying the setting of concrete. While
the popular motion picture film slows down normally fast processes,
Mr. Johnson's automatic camera speeds up the normally slow, so that
one can, for instance, observe in a few minutes the physical and
chemical phenomena of many days. Motion pictures have already
had a marked influence on social conditions; may they not have a
bright future in science ?

♦

PRESS OF
J. B. LIPPINCOTT COMPANY
PHILADELPHIA

Digitized by

Google

Journal of The Franklin Instititte.
OFFICERS FOR 1919

PR£SIDENT Walton Clark

VICB-PRBSIDBNTS HeNRY HoWSON

Coleman Sellers, Jr.

SBCRSTART R. B. OWENS

TREASURER CyRUS BoRGNBR

BOARD OF MANAGERS

Gellert Allem an George R. Henderson

Francis T. Chambers Charles A. Hexamer

G. H. Clamer George A. Hoadley

Theobald F. Clark Harry P. Keller

Charles Day Robert W. Lesley

Kern Dodge Marshall S. Morgan

W. C. L. Eglin Edw. V. McCaffrey

Walton Forstall Lawrence T. Paul .

Benjamin Franklin James S. Rogers

Alfred W. Gibbs Geo. D. Rosengarten

Alfred C. Harri5$on E. H. Sanborn

Nathan Hayward William C. Wetherill

board of trustees

Joseph C. Praley, President
William L. Austin John Gribbrl

Charles £. Brinley Alfred C. Harrison

Walton Clark Frederick Rosengarten

The Board of Trustees was formed in accordance with the following
By-Laws passed in the year 1887:

All Real and Personal Estate of the Institute which may hereafter be acquired
by voluntary subscription or devise, bequest, donation, or in any way other than
through its own earnings or by investment of its own funds, saving where the
donors shall expressly provide to the contrary, shall be taken as acquired upon
the condition that the same shall be vested in a Board of Trustees, who shall be
appointed in the manner hereinafter indicated. Unless the title to such property
shall be directly vested in said Board of Trustees by the donors, the Institute,
by deed attested by the President and Secretary, which they are hereby author-
ised to execute and deliver, shall forthwith convey the same to said Trustees,
who shall hold it in trust for the purposes specifically designated by the donors;
or. if there shall be no specific designation, for the benefit of the Institute in the
way and manner hereinafter provided, so that the same shall not, in any event
be liable for the debts of the Institute.

This method of separating the body holding the principal of the various
funds froin the Board of Managers, the spending body, is an original idea
of The Franklin Institute and it is hoped it will appeal to friends who may
desire to create funds to further the objects ot the Institute, and the
▼arious branches of science in which they may be interested.

Digitized by

Google

Journal of The Franklin Institute.

MEMBERSHIP.
Terms and Privileges.

THE MEMBERSHIP OF THE INSTmiTE is divided into the following
dasses, viz. : Resident Members, Siockholders, Life Members, Permanent Members,
Nan- resident and Associate Members,

Any one interested in the purposes and objects of The Institute and ei-
pressing a willingness to further the same may become a member when proposed
by a member in good standing and elected by the Board of Managers.

TERMS. — Resident members pay Fifteen Dollars each year. The payment
of Two Hundred Dollars in any one year secures Life Membership, with exemp-
tion from annual dues.

STOCK. — Second-class stockholders pay an annual tax of Twelve Dollars
per share, and the holder of one share is entitled by such payment to the
privileges of membership.

PRIVILEGES. — Each contributing member (including non-residents) and
adult holder of second-class stock is entitled to participate in the meetings of
The Institute, to use the Library and Reading Room, to vote at the Annual
Election for officers, to receive tickets to the lectures for himself and friend, to
•ttend the Section meetings and to receive one copy of the Journal free of
charge, except associate members, who may not take part in elections.

PERMANENT M£MBERS.~The Board of Managers may grant to any
one who shall in any one year contribute to The Institute the sum of One
Thousand Dollars a permanent membership, transferable by will or otherwise.

NON-RESIDENT MEMBERS.— Newly elected members residing perma-
nently at a distance of twenty-five miles or more from Philadelphia may be
enrolled as Non-resident Members, and are required to pay an entrance fee of
Five Dollars, and Five Dollars annually. Non-resident Life Membership, $7Soa

Contributing members, if eligible, under the non-resident clause, on making
request therefor, may be transferred to the non-resident class by vote of the
Board of Managers, and are required to pay Five Dollars annually.

ASSOCIATE BfEMBERS.— Associate members are accorded all the privi-
leges of The Institute, except the rijjht to vote or hold office, upon the payment
of annual dues of Five Dollars. This class of membership is limited to persons
between 'he ages of seventeen and twenty-five years. Upon reaching the age
limit they become eligible to the other classes of membership.

RESIGNATIONS must be made in writing, and dues must be paid to the daU
of resignation.

For furth'^r information and membership application blanks address the
Secretary of Thb Institute.

Digitized by

Google

AWARDS BY THE INSTITUTE

The following awards are made by The Franklin Institute :

The Franklin Medal (Gold Medal and Diploma) .—This medal i»
awarded annually from the Franklin Medal Fund, founded January i, 1914,
by Samuel Insull, Esq., to those workers in physical science or technology^
without regard to country, whose efforts, in the opinion of the Institute,
acting through its Committee on Science and the Arts, have done most to
advance a knowledge of physical science or its applications.

The Elliott Cresson Medal (Gold Medal and Diploma) .—This medal
is awarded for discovery or original research, adding to the sum of human
knowledge, irrespective of commercial value; leading and practical utiliza-
tions of discovery; and invention, methods or products embodying sub-
stantial elements of leadership in their respective classes, or unusual skill
or perfection in workmanship.

The Howard N. Potts Medal (Gold Medal and Diploma).— This medal
is awarded for distinguished work in science or the arts; important
development of previous basic discoveries; inventions or products of
superior excellence or utilizing important principles; and for papers of
especial merit that have been presented to the Institute and published in its
Journal.

The Edward Longstreth Medal of Merit (Silver Medal and Diploma).—
This medal, with a money premium when the accumulated interest of
the fund permits, is awarded for meritorious work in science or the
arts; including papers relating to such subjects originally read before
the Institute, and papers presented to the Institute and published in its
Journal. In the event of an accumulation of the fund for medals beyond the
sum of one hundred dollars, it is competent for the Committee on Science
and the Arts to ofTer from such surplus a money premium for some special
work on any mechanical or scientific subject that is considered of sufficient
importance, or for meritorious papers presented to the Institute and pub-
lished in its Journal.

The Certificate of Merit.— A Certificate of Merit is awarded to persons
adjudged worthy thereof for their inventions, discoveries or productions.

The Boyden Premium.— Uriah A. Boyden, Esq., of Boston, Mass., has
deposited with The Franklin Institute the sum of one thousand dollars, to be
awarded as premium to "any resident of North America who shall determine by
experiment whether all rays of light, and other physical rays, are or are not
transmitted with the same velocity."

For further information relating to these awarde apply to the Secretary of the Inatitute,

Digitized by

Google

Journal of The Franklin Institute.

THE FRANKLIN INSTITUTE AWARDS

Notice is hereby gi^en that THE FRANKLIN mSTITUTE,

through its Committee on Science and the Arts,

proposes to award

THE HOWARD N. POTTS GOLD MEDAL

CLARENCE P. LANDRETH

PHILADBLPHIA. PA.

For his

ELECTROLYTIC SEWAGE PROCESS

Any objection to the above projposed award, based on
evidence of lack of merit, should be communicated within
three months of the date of this notice to the Secretary of
THE FRANKLIN INSTITUTE, Philadelphia.

R. B. OWENS,

Secretary.

HALL OF THE INSTITUTE
June 1, 1919.

Digitized by

Google

Journal of The Franklin Institute.

THE FRANKLIN INSTITUTE AWARDS

Notice is hereby siven that THE FRANKLIN INSTrTUTE,

throuc^ its Committee on Science and the Arts,

proposes to award

THE HOWARD N. POTTS GOLD MEDAL

Jomtly to

REYNOLD JANNEY

NBW YORK, N. T.
AND

HARVEY D. WILLUMS

WALLINGPORD. CONN.

For the Invention of the

WATERBURY HYDRAULIC SPEED GEAR

Any objection to the above proposed award, based on
evidence of lack of merit, should be communicated within
three months of the date of this notice to the Secretary of
THE FRANKLIN INSTITUTE, Philadelphia.

R. B. OWENS,

Secretary.

HALL OF THE INSTITXTTE
June 1, 1919.

xiu

Digitized by

Google

JOUBHAl. OF The FsaKKUQI IkSTITUTB — ^ADVERTISEMKinSw

FIDELITY TRUST COMPANY

Hob. 32S-33I CHESTNUT ST. FU. 43-53 SOUTH FOURTH ST.

BROAD ST. OFFICE: N. E. COR. BROAD AND CHESTNUT STS.

CmpamL $5,000,000
Smrpim». $16,000,000

Piy.

1 rarti of Efcfy DuuipliiML
forRc^kB«|br.|»oofVadta. Sccsiba a^l VaUble* Takes for Sale

Wak S^ely Kc|« Wilkoat ClHive.

HAMLIN Jb MORRISON

ANALYTICAL CHEMISTS

FORREST BUILDING
FHaja>ELPHlA

RieUe Brat. Testang Macbioe Co.

1424 N. tlk St.. PtiliiliMii. Pa.

Tsiephooe CooncctkM. Cable, " Riehle. "

Concspoodencc Solicited from Parties deairinK
ftha Latcat laproTed Unhed States Standard
Tetdac Machinery and AppUanccsof all Tarienes
aod capacities.

BANCROFT A, BROTHER

KSTAauBHCD isa«

MSHMMCr M AU ITS HUHaRS

244 Drexel Baildlnf . PhitedelpMM

STEAM FITTING
PLUMBING

John Borden and Bro.

««7 NortK l«tK Str*«t

The MOORE & WHITE CO.

PHILADELPHIA. PA., U. S. A.

Paper-making Machinery
Builders of j Fdction Clutch Pulleys
Variable Speed Chanffes

T9mt conrtaaj In mentloniiif the Joamal will ba appr^lafad

Digitized by

Google

Journal of The Franklin Institute — Advertisements.

"NICE"

PAINTS, VARNISHES, FILLERS

For Every Purp<M«

EUGENE E. NICE, Mfr.

272.274 South SmoimI Straet PhiUdalphi*

QUALITY
DELIVERY

AND A

FAIR PRICE

The Constituents
of Good Printing

AU to be had for the maldng

Bradley Printing Co.

Printers— EnsraTera
BiMik Book Maker*

1214 Sansom Street, Phila.

SAMUEL P. SADTLER & SON

CoMolliDt CbeniaJ Eapem

Analyses and reporu made in aU branchss n*
iodnstnal and applied cbemistry. I<lxpert assist-
ance in the development of chemical processei
and patents, and preparation of tssttmony b
chemical patent soiu. Raw materials and wastt
piodacts of mannfactnring processes spscialb
stadled and reported upon.

Office and LAboratory-210 S. 13th Sl.,Phaa

Experimental Shop — Cbettnut Hill, Fa.

PATENTS

Frocorcd for In-
ventions and de^
sians. Trade-
marlis Registered, Pstcnt Causes, V zsmlnations^
Searches, etc. Call or send for Book ol Instmctionft

WIEDKRSHKIM ft FAIRBANKS

John A. Wiedershcim DeLong Huildhij

Wm. Canet Wiedciseim IS3S Chestnnt Sc«

H. Hay ward Fairbanks

Pbiladelphle

Drawing Materials

Surveying Instnimentf

Bine, Brown and Direct
Blaclc-Liu« I'riut I'apenr

F. WEBER & CO.

1125 Chettnut Street

'^ar€eDeralors

:VEL GEARS
»oretically Correct

lesfor Cutting Worm. Spirals
kluid Ellipricair.earWhcelf

TIE BILGRAlll
MACnNE WORKS

1229 Spring Gsidea Si.
PhiU..Pa.

Philadelphia Book Co.
ENGINEERING AND
TECHNICAL BCX)KS

17 SOUTH NINTH STREET

Bel Telephone Wshml 1002

Your courtesy In mentlonlnf the Journal will bt appreciated

Digitized by

Google

Journal of The Franklin Institute — Advertisements.

CONSERVE ELECTRICITY

Using the wrong type of lamp is just as extravagant, pro-
portionately, as buying two or three times the amount of coal
you need and throwing out the surplus with the ashes.

If you will see to it that there are

MAZDA LAMPS

in every lighting socket in your home or place of business
you can be sure that you are getting the fiill worth of your
money, not only in the greater amount of light for the current
consumed, but in the greatly improved quality of illumination.
Mazda lamps give three times as much light for the same
money as the old carbon or Gem lamps. Electric illumination
by Mazda lamps, therefore, is the most economical lighting i
method, whether for residence, store or factory. X

♦•♦♦•<

THE PHILADELPHIA ELECTRIC COMPANY ♦

QgOMMERC/AL

CY RUS BORGNER COMP ANY, soccessors to

Your courtesy Id mentioning the Journal will be appreciated
xvi

Digitized by

Google

A' 11'

Vol 188 AUGUST l«i9 Na 2

1826 Journal 1919

The Franklin Institute

Deroted to Scwbm and Um M^chaaic ArU
EDITED BY R. B. OWENS, E JS., MJk., Di3c., FJ15.C.
AModato Editon:

BRIG. OBV. JAIUB ALUS A. B. KKNNBLLT, 80.D. C. P. tncINMBn, Pa.D.

mLDKB D. BANCBOFT, JPa.D. GABTAMO LAKSA, C.B. 8. W. 8TRATXON, 80.D.

OOU JOHN J. CABT7, BJ>. RALPH MODJBBKI, D. Baa. v CHIBP CON. D. W. TATLOB,

ALLKBTON & CUBHHAll, PB J>. L. A. 08B0BNB, M JL ' U. 8. N.

OOL A. 8. BTB, F JLB. ALBBBT 8AUVBUB, BA y 8. M. VAUCLAIN, 80.D.

W. J. HOMPHBBTB, PS.D. BDGAB P. 8MITB, PB.D{ B. 8. WOODWABD, Ph.D

HABBT P. KXLLBB, Pa.D. If AJ. GBN.GBO. O. 8QUIM«A.D. A. P. SAHM, PH.D.

CoBunitlaa on PvblicalioBiT^'^v^

GBOBGB D. BOflSNGABTBH, CHAIBMAlf
G. H. GLAMSB GBOBGB A. HOADLBY W. C. L. BOUB B. H. BANBOBB

CONTENTS
Electrical Treatmeot of Sewage : The Landreth Direct Oxidation ProceBS . . 157

Henbt Jericain Maudb Cbbighton and Benjamin Franxun
Some Remarks Concemlns: the Heat Treatment of Steel and Their Appllca*

tion to the Treatment of Steels Used for Airplane Motors 189

Albert Sauvettr
Oimbal Stahillzatlon 199

"^ V. BUBH

The Photometric Scale - * - 217

Hbbbkbt E. Iyss

Development of an Airplane Shock Recorder 237

A.F. Zahm
Pitch Pockets and Their Relation to the Inspection off Airplane Puts .... 245

J. R. Watkinb
Recent Progress In the Mantifiacture of Glasses for Protecting the Eye from

Injuriotts Radhitions v 255

W. W. COBUBNTl

Notes from the U. S. Bureau of Standards: 263

Some Optioal and Photoelectrioal Properties of Molybdenite.

A St an da r d i sed Method for the Determination of SoUdifioation Points, Bspecially of Naphtha-

IssM and Paraffin.
The Standardisation of the Sulphur BoUing Point.
Metalfio Coatings for the Rust-proofing of Iron and Steel.

I^eakage Resistance of Eleotrie Railway Roadbeds and Its Relation to Bfootrolysis.
The Constitution of Alominmn and Its Light Alloys with Copper and with Aluminum.

Notes from the U. S* Bureau off Chemistry: 209

The Constitution of Gapsaiein. the Pungent' PrineifJe of Capsicum.
The Zinc Content of Some Food Products.

Notes from the U. S. Bureau of Mines: 271

Method of Administerins Leases of Iron Ore Deposits Belonging to the State of Minnesota.

ElectrodoKMition of Qola and Silrer from Cyanide Solution.

Eleetrie Furnace Laboratonr Equipment at Seattle Station, U. S. Bureau of Mines.

Carbon Black from Natural Qas.

Minor Notes.

The Ftanklln Institute: 279

Libnry Notes.
Conespondenee.

BookNotfce 285

Pnhlk:ntlons Received 285

Carrent Topics . 187, 188, 198, 216, 236, 244, 253, 254, 261, 262, 268, 270, 278, 286, 287

ii, iz-xiii

Mentblr by
THE FRANKLIN INSTITUTE OF THE STATE OF PENNSYLVANIA, PHILADELPHU

PIVE DOLLAHS per year CPomgii PoMge Additfooai.) SINGLE NUMBERS, nPTY CENTS
MmmtA at tbc Pom oa<» it PhUtddpUs. Pa., m teo>Bd<lM« mattnr. Copyright. 1919. by Tbs PsAXELni IviTlTVTB

jLeeeptance for maUing at special rate of postage provided for in section 1103, Act of
October 3. 1917, authorixed on July 3, 1919.

Digitized by

Google

INDEX TO ADVERTISERS

PROFESSIONAL CARDS. PAGES XIV AND XV

PAOB

American Pulley Co., Third Gover page
Ai^gUtodUleM Bearing Co i

Baldwin Locomotive Works

Fourth cover page

Bancroft & Brother, Insurance,
Philadelphia xiv

Bamett, G. & H. Co., File Works,

S Philadelphia . . Fourth cover page

Bllgrsm Machine Works, The, Bevel
Gears, Philadelphia • zv

Borden, John, & Bra ziv

Borgner, Cvrus Co., Fire Bricks,
etc., Philadelphia zvi

Bradley Printing Co., Philadelphia. . zv

Chester Steel Castings Co., Phila-
delphia vii

Commercial Photo Engraving Co. . . zvi

Fidelity Trust Co ziv

Franklin Institutb, Announce-

ments .

Franklin Institute, Awards
of xi-zii-xiii

Franklin Institute, Certificate
of Membership, Terms and
Privileges x

Franklin Institute, Officers
and Trustees ix

Hamlin & Morrison, Analytical
Chemists, Philadelphia ..... xiv

Keystone Screw Co. .

viii

Leeds & Northrup Co., The, Electri-
cal Measuring Instruments.
Philadelphia.'. iv

LippiMott, J. B. Company, Pub-

McCaffrey File Co. . Fourth cover page

Moore & White Co., The, Paper-
making Machineiy xiv

Nice. Eugene E.. Mfr. of Paints,
VarnShea, Fillers, etc. . . . . . zv

Oldach Company, Book-Bhiding . . Iv

Olsen, Tinius, Testing Machine Co.,
TestingMachkiesandHydraulic
Presses vi|

Philadelphia Book Co xv

Philadelphia Electric Co. zvi

Phosphor Bronae Smelting Co., Phila. ziv

Powers - Weightman • Rosengarten
Co., Chemists i^

Rieh1« Bros. Testing Machine Co. . . ziv

Sadtler, Samuel P.&Son, Consulting
Chemical Ezperts. xw

Sellers, Wm. Bt Co., Inc., Machin-
ists, Philadelphia v

Troemner, Henry, Scales vii

United Gas Improvement Ca . . • . vi

Watson & McDaniel CO., Philadel-
phia iv

Weber, F. & Co., Draughting and
Engineering Instruments .... zv

Wiederaheim & FalilMmks, Patents . zv
Wood, Alan, Iron and Steel Ca • . viil

Digitized by

Google

Journal of The Frankun Institute — ^Advertisements.

Your courtesy in mentioning the Journal will be appreciated

Digitized by

Google

Journal of The FkAKKLiN Institute.
THE FRANKLIN INSTITUTE

ANNOUNCEMENTS

MEETINGS

COMMTTTEB ON SCIBNCB AND THE ARTS. First WedoMday •!

each month, 8 P.M. (except July and August).
BOARD OF MANAGERS. Second Wednesday of each month, 330 P Ji.
INSTITUTK. Third Wednesday of each month (except June, July*

Aagust and September), 8 P.M.
SECTION liEETINGS. Thursday Evenhigs (except we^ of Institute

Meeting), 8 o'clocii. October 1 to April 30.

PAGB

Officers for 1919 • . . . . . ix

Membership • • • x

Awards and Premiums • • . • • • xi,xii,xiii

The Franklin Medal

Elliott Cresson Medal

Potts and Longstreth Medals

Certificate of Merit

Hoyden Premium

CHANGES OF ADDRESS

Members are particularly requested to inform the Secretary
of changes of address.

Digitized by

Google

Journal of The Franklin Institute— tAdvertisements.

THE LATEST SCIENTIFIC BOOKS

The Chemical Analysis of Iron

By ANDREW ALEXANDER BLAIR

mattrat«d, N«w •isbth cdilioiB. 8to. $S,00 B«t

! A Short Handbook of Oil Analysis

By AUGUSTUS H. GILL, Ph J>.
RcTiMa and •bWswI. Eighth MUtioB, 12mo. $2.50 B«t

Aids in the Commercial Analysis of Oils, Fats
and Their Commercial Products

By G. F.PICKERING
MaarteUaa. Sre. $2.80 nat

Modem Shipbuilding Terms Defined and Illustrated

By F. FORREST PEASE
DfaMtratad. 12mo. $2.00 nat

The Construction and Maintenance of VesselsBuilt of Steel

B7 THOMAS WALTON
LargaSro. $7.00 aat

Present-Day Shipbuilding

By THOMAS WALTON
nhwtratad. Larva Sro. $3.50 nat

Know Your Own Ship

By THOMAS WALTON
Ninth adMom RariMd andl iilMtratad. 12mo. $3.00 nat

A Handbook of Briquetting

B7G.FRANKE
TramUtad by FRED. C. A. H. LANTSBERRY, M.Sc.. ia 2 toU., aaeh eompiata ia itaalf
VOL. I.— THE BRIQUETTING OF COALS, BROWN COALS AND OTHER FUELS

Nina plataa aad 22S iOoatratiaiis ia tazt. Sra. $8.00 aat
VOL.IL-BRIQUETTING OF ORES, METALLURGICAL PRODUCTS, Etc
4 plataa. 78 flhutratioiu in tazt. 8to. $4.80 nat

Methods of Measuring Temperature

By EZER GRIFFITHS, S J>.Sc.
81 iUiMtratiaiM. Sro. $2.78 nat

A Manual of Dyeing

By E. KNECHT, CHRISTOPHER RAWSON aad RICHARD LOWENTHAL, B3e.

Third adiHan. 2 Tohamaa. VaL I coataina 86 iUastvatiam, 8 fail-paffa plataa, 371 pacaa

VaLII.88ilhutratiaBs,831paffaa. Larva 8to. 2Tob. $14.00 aat

Land and Marine Diesel Engines

By GIORGIO SUPINO
Traadatad byUaat-pCoaidr. A.a BREMNER.R.N., aad JAMES RICHARDSON. B.Sc.(Ea«.^

LoBd.,A!M.Iaat.C.E.
19 platas aad 380 ilhwtratioaa ia tha taxt. $4.80 aat

Steel: Its Metallurgy and Mechanical Treatment

By HARBORD AND HALL

Fifth aditiaa. 1027 pacat. 84 foMiav plataa. comprisias 118 ficaras. Orar 800 OhMtro-

tiam ia taart, aad aaariy 80 pliatoBiicrographa al ataal aactioaa. 28vola. $13.80 aat

J. B. LiPPiNcoTT Company Imui^i^

Tour courtesy In menttoning the Journal will be appreciated

Digitized by

Google

Journal of The Franklin Institute — ^Advertisements.

BOOK-BINDING

EDITION

OLDACH COMPANY u.;;;;^;

61 N. SEVENTH STREET. PHILA. m MKHCBiNOiNa

THE LEEDS & NORTHRUP CO.

ELECTRICAL MEASURING INSTRUMENTS

ApptfatDs (or the meatuieiiient of leaitaaoe, capMity and hiductince. Temperatuie nwiuring
derioM. Cable tertmg appaiitiH. Eledncal neMureaieatt laboratoriet eq ui pped.

4901 STENTON AVENUE PHILADELPHIA

The McDaniel Improved Steam Trap

DISCHARGES CONTINUOUSLY AND NEVER BLOWS STEAM
WATER GAUGES ARE USED TO SHOW THE WORKING OF THE TRAP

Made Extrm HaaTj for High PraMine

W« ftlso nttnuActuie Redudng VaIto. Eztaaint npc Haads. Sac i mw m far tJw

WATSON & McDANIEL CO., titiTdiiliSr^:

Your courtesy In meiitioniiig the Journal will be appreciated
iv

Digitized by

Google

JOUKNAL OF Thb FraNKUN INSTITUTE — ^AdVESTISKMBNTS.

Philadelphia, Pa.

LABOR SAVING

MACHINE TOOLS

Boring and Turning Mills Diilling and Boring Madunes
Planing Machines Slotting Machmes

TOOL GRINDING MACHINES
DRILL GRINDING MACHINES

Whed Ladies Axle Lathes

Steam Hammers Sand Mixing Machines

INJECTORS FOR BOILERS

(Locomothre — ^Marine — Slationary)

Shafts^ Pulleys^ Hangers, Couplings, &c.

For Economical Power Transmission
(BELT-ROPE-GEARS)

Y«ar eoortMj In Beatloiiliif the Jonrnal will tot appndatod

Digitized by

Google

Journal of The Franklin Institutb-^Advertisements*

The Uiiited Gas Improvement
Company - Philadelphia, Pa.

LESSEES, OPERATORS AND BUILDERS OF

GAS WORKS

LARGEST BUILDERS IN AMERICA OP

CARBURETTED WATER GAS PLANTS

Sole American Builders of the
Standard Double Superheater
Lowe Water Gas Apparatus.

System for Controlling Air and
Steam Supply to Water Gas
Apparatus.

Waste Heat Boilers for Water
Gas and Coal Gas Appa-
ratus.

Vertical Retort System.

Tar Extractors for Carburet-
ted Water Gas.

Gas Analysis Apparatus.
Hygrometers.
Photometrical Apparatus.
First Aid Kits for Gas
Asphyxiation.

First Aid Kits for Electric
Shocks.

First Aid General Wall
Cabinet.

Your courtefj in mentioiiliig the Joarnal will be.apprMlatod

Digitized by

Google

JOURNAJL OF ThB FraNKLLM. INSTITUTE — ^ADVEETISBMBNT^.

IMO Sandardof Excellence i9i%

HENRY TROEMNER'S

Aasay and Analytical
BALANCES and WEIGHTS

For AU SehmUfk Utm

Used by the Goverament of United
States, Canada, Mexico, and China

HENRY TROEMNER
JVo. 911 Arch St,, Philadelphia, Pa., U. S. A,

TESTING MACHINES

and

HYDRAUUC PRESSES

We are always prepared to make tests of all kinds

TimUS OLSEN TESTING MACHINE CO.
500 North Twelfth Street, Philadelphia, Pa.

J. E. LONERGAN CO.

Manufacturers of

BOILER, STEAM AND GAS ENGINE SPECIALTIES ; POP SAFETY

AND WATER REUEF VALVES ; WHISTLES, OIL CUPS, PRESSURE

GAUGES, H.-P. WATER GAUGES

211-213-215 Race Street, PkaadelpU, Pa.

^^nr^l-^l"^ Y OPEN HEARTH of every dS-

^ I Li Li I — ^^— — ^— ^^ tcriptionfor

.^^ I r^ 1^ I Electricml Machinery, Dredging, Rollinff. and

UJ A, "-«*-*"-* Snnr Mill Machinery, Locomotive, Railroad,

and Bridge Work, etc.

CEMENTATION f tflfiSHT.^

t UA /^ I I I Al V 1 i. J *>P* Superior for Crank-ahafU. Gearing, and
^^^A aKi^ JL a± ^ ^» ^ ^^ other purpoaet where great wearing retulta art

required.

Correspondence Soheiied

CHESTER STEEL CASTINGS CO.

Works, Chester. Pa. Office. 407 Sansom St. Phiku. Pa.

Tovr coartesj In metttlonlng the Jonmal wiU b» appreciated
vii

Digitized by

Google

Journal of The Franklin Institute — ^Advertisements.

Machine Screws

We cany a large itock of Iron and Brats in the above shown ttandaxd heads.
We fumiah to order any Special Heads, to sample or drawing.

KETSTONE SCREW CO., Philadelphia

Ofllc« and Works: itUi ST. ft LBHIOH AYS.

RICHARD G. WOOD. Pnt't W. W. LUKENS. Sk> mkI Ami Tmm.

I. R. JONES. Vi»A«*i md TiMt. HOWARD WOOD. JR.. Ami SkV

AMmm EiteMbiW /a26

Alan Wood Iron and Steel
Company

Maiiafaetarvn of

PIG IRON, BASIC OPEN HEARTH STEEL BILLETS,
BLOOMS, SLABS^ STEEL SHEETS

HEAVY SHEARED PLATES

SPEOALTIES^

LoooMOthro Jookol Blao AMOolod. Bolii BoOor, Gas HoUor. Com^otod.

A.W.aoaii.M.F. CoMRoUodSbooto. Piekloa and CoM RoOod Skooto.

Water Plpo awl Llaiil Piatoo.

**A.W.**DiiMadMKi'*A.W.*' ROibed Patten Ruled Sled Floor Pblai

— — — ^— 5tcet Fumbhtd on AppUcaHcn -^— ^— ^—

Now York
SOClMrdi

^ Widoner Building, Philadelphia

Tonr eoaitaty In BOBtloBlag tao Joamal will bt apprteletad

vii«

Digitized by

Google

AUG 11 1919

Journal

The Franklin Institute

Devoted to Science and the Mechanic Arts

VoUM AUGUST, 1919 No. 2

ELECTRICAL TREATMENT OP SEWAGE: THE
LANDRETH DIRECT OXIDATION PROCESS.*f

HENRY JERMAIN MAUDE CREIOHTON,

Department of Chemistry, Swarthmore College,

and
BENJAMIN FRANKLIN,

Civil Engineer.
Members of the Institute.

I. IHTRODUCTIOV.

The first mention of the use of electricity in the purification
of sewage is contained in an English patent, No. 1499, issued
to J. Chisholm in 1856, for a process of disinfecting and deodoriz-
ing by electric or galvanic agency noxious or infected matters,
such as occur in cesspools or sewers. No successful application
seems to have been made of this process or of a number of other
similar processes patented between the years 1870 and 1886.

Among the best known of the electrical processes is that
invented by Webster, and installed experimentally at Crossness,
England, in 1889, to treat London sewage. In tihis process the
raw sewage flowed, in contact with iron electrodes, through long

* Communicated by the Author.

fThis paper embodies the results of an investigation of the Landreth
Direct Oxidation Process by the Committee of Science and the Arts of The
Franklin Institute.

INote.— The Franklin Institate is not re«ponsibIe for the statements and opinions advanced
BTContributOTS to the Journal.]

Digitized by

Google

158 H. J. M. Creighton and Benj. Franklin. [J. F. I.

troughs, each section of which was made of two, four or more
longitudinal parts bolted together but insulated from each other.
In the electrolysis cell a current density of 0.9 ampere maintained
by an electromotive force of about 2 volts was employed. For the
treatment of raw sewage it was estimated that 240 pounds of
iron and 450 kilowatt hours of electrical energy would be con-
sumed per million gallons. In this process most of the nascent
oxygen liberated at the anode was consumed in oxidizing the iron
of the electrode, and the oxide thus formed acted as a precipitating
agent on the sludge of the sewage. The process, therefore, was
mainly one of chemical precipitation by means of the oxide of iron
formed by the action of the electric current.

Plants operating along the general lines of the Webster process
are in use in Santa Monica, California, and in Oklahoma City,
Oklahoma. While no careful studies have been reported from
either of these plants, it is understood that, for a time at least,
both gave satisfactory results so far as purification was concerned.

To a second type of so-called electrical process for the purifi-
cation of sewage belong those in which nascent chlorine, liberated
by the electrolysis of a chloride, acts as a disinfectant. A process
of this kind was first developed by E. Hermite, in 1887. The
sewage was mixed with chlorides of magnesium, calcium or
sodium, and the liquid thus charged was passed in thin sheets
or streams between electrodes. In a similar process invented by
A. E. Wolff, a strong brine solution was electrolyzed, and the
resulting chlorine and caustic soda were allowed to recombine
in the form of sodium h3T)ochlorite, the solution of this latter
substance being used for purifying the sewage. In 1893, the
sewage of about thirty dwellings at Brewster, N. Y., was treated
by the addition of hypochlorite solution made in this way, under
the direction of the Health Department of New York City.* For
every million gallons of sewage treated, 1600 pounds of salt were
used, and the plant required an electric current of 700 amperes
at 5 volts. ** This seems to have been the first plant established
for the specific purpose of destroying bacteria. Before that time
the removal of organic matter had been the aim." ^

Extensive investigation has shown that electrical treatment of
sewae:e is capable of practical use,- but that the precipitants and
disinfectants prepareci by electrolysis will have the same efficiency

' Eng. News, 30, 41 (1893)-

* Water Supply Paper No. 229. p. 27, U. S. Geol. Survey.

Digitized by

Google

Aug., ipip] Electrical Treatment of Sewage.. 159

and no greater efficiency as when manufactured outside. As
Kennicut, Winslow and Pratt point out,^ " the important ques-
tion is whether electrolysis in the presence of the sewage is or is
not the most economical method of preparing and applying such
precipitants and disinfectants as are needed. If the problem is
regarded from this practical standpoint and without vague mysti-
cal conceptions of the purifying agency of electrical energy as
such (which are apt to cloud the matter in the lay mind), a sound
conclusion may be reached in any given case by a careful con-
sideration of operating costs ; and this conclusion will not gener-
ally be in favor of electric treatment."

The failure of sedimentation to clarify sewage thoroughly led
to the introduction in England, about i860, of a method known
as the chemical precipitation of sewage. This consists in adding
to the sewage certain chemical compounds which produce a volu-
minous flocculent precipitate which, when the sewage thus treated
is allowed to remain quiescent in a large tank for some time,
settles to the bottom of the tank, carrying down with it the sus-
pended solids of the sewage, leaving a clear supernatant liquid.
The chemical compound first employed for this purpose was lime,
which was added to the sewage in the form of milk of lime. The
action of lime depends upon its combining with the carbonic acid
and soluble carbonates in the sewage to form insoluble calcium
carbonate, which in settling out carries down with it the sus-
pended solids. The quantity of lime which it is necessary to
employ depends upon the character of the sewage, an acid sewage
requiring more than one which is neutral or alkaline. If too little
lime is added to the sewage, sedimentation takes place slowly and
it is impossible to obtain a clear effluent ; on the other hand, with
the addition of too much lime, varying quantities of the suspended
organic matter in the sewage are rendered soluble, thus causing
the effluent to be more putrescent and obnoxious than that from
ordinary sedimentation.

In the Landreth Direct Oxidation Process for the treatment
of sewage, both electricity and lime are employed. The efficacy
of the process, as will be seen later, depends upon the combination
of these agents, neither electricity nor lime alone producing such
good results. The electric current liberates at the electrodes
oxygen and hydrogen which in the nascent state are claimed to

• Kennicut. L. P., Winslow, C. E. A., and Pratt, R. W. : " Sewage Dis-
posal," 1919. John Wiley & Sons, New York.

Digitized by

Google

i6o H. J. M. Creighton and Benj. Franklin. [J.F.L

promote the destruction of pathogenic bacteria, and a reduction
of the nitrogenous organic matter to albuminoids, peptones and
amino compounds, which are subsequently oxidized to nitrites,
nitrates and carbon dioxide. The presence of lime furnishes
not only an alkaline medium which lowers the electrical resistance
of the sewage and renders the electrodes passive, thus very greatly

Fig. I.

decreasing the quantity of iron which passes into solution from
the anode, but it also aids in sedimentation. The process differs
from others that employ electricity, in that purification is effected
neither by the action of dissolved iron as a coagulant, nor pri-
marily by the disinfecting action of nascent chlorine produced
by electrolysis.

The Landreth process has been extensively studied at the
750,000 gallon unit installed at Elmhurst, Long Island, in 191 5,
by Messrs. Mason, Olsen and Mailloux, and by the Bureau
of Sewer Plan of New York City ; and later at Decatur, Illinois.
Since then the process has been somewhat altered, and in the
Spring of 1918 a plant with a million gallon unit embodying the

Digitized by

Google

Aug,, 1919] Electrical Treatment of Sewage.

161

inventor's improvements was erected at Easton, Penna., by Mr.
Landreth for demonstration purposes.

Fig. 2.

n. DBSCRIPTIOlf OP PROCBSS AVD PLANT.

The plant at Easton occupies a comer site, at Front and Spring
Garden Streets, adjoining one of the city recreation parks, and
is only two squares distant from the business centre of the city.

Digitized by

Google

i62 H. J. M. Creighton and Benj. Franklin. [JF. I-

Its location in the heart of the residential district and the entire
absence of complaints and unfavorable comments indicate that the
plant is not considered a nuisance, and that the nearby residents
are not annoyed by odors or other objectionable features. The
plant consists of a one-story frame building, 48 feet long and
33 feet wide (Fig. i), the interior construction of which is
illustrated by the plan shown in Fig. 2.

Sewage is obtained from the Front Street sewer, an i8-inch
concrete dam having been placed below the lateral which delivers
it to the plant. The area drained by this sewer is 104 acres and
includes two hotels and one brewery. The approximate estimate
of the population tributary to the sewer is 7000.

On entering the plant the sewage passes through a coarse
screen 3'6"x4', framed with bars 0.25" thick and 1.5" deep,
placed 1.5" apart from centre to centre, and is elevated by means
of a 6" submerged centrifugal pump to the raw sewage flume,
from where it flows throughout the plant by gravity. The raw
sewage flume distributes the sewage over a flat inclined screen,
6'6" X 8', having six 0.25" perforated holes to the square inch.
These perforations are made so that the smooth surface is
upwards. The material caught by this screen is removed con-
tinuously by five brushes 60" in length arranged on a traveler.
The sewage passes through this screen to a grit chamber and
then on to a 3-foot measuring weir, the crest of which is of steel.
The gauge for measuring the flow is placed four feet back from
the crest of the weir, the zero of the gauge corresponding to the
elevation of the weir .crest. The discharge has been calculated by
the Bazin formula which gave results proportional to the depth
of the discharge over the weir. After being mixed with milk of
lime at the spillway of the weir, the sewage passes through the
electrolytic apparatus and enters the observation flume, from
which it can be either passed through a sedimentation basin or
discharged directly into the river.

The solid material obtained from the bar-screen which pro-
tects the centrifugal pump consists largely of paper and labels
from the bottling house of a nearby brewery and amounts on an
average to about 20 pounds per million gallons. Above the g^t
chamber the flat screen collects from two to three pails, each of
three gallons, per 24 hours. The greatest part of these screenings
consists of grain and hops from the brewery and vegetables from
the hotel kitchens, very little faecal matter being found.

Digitized by

Google

Aug., 1919.] Electrical Treatment of Sewage. 163

The electrolytic apparatus (Fig. 3 and Fig. 3a) consists of a
horizontal cypress box, 27^3" long, 3' wide and 2*9" deep, mounted
on supports 18" above the floor. The top of the apparatus, which is
removable, is made in two sections bolted to the sides and made
water-tight with a rubber gasket. Vents are provided in each
section of the top for the gaseous products of electrolysis, and
a series of valves in the bottom of the tank serve to remove any
sediment that may be deposited.

Fig. 3.

Internally, the tank is divided into eleven spaces, each of which
contains two banks of electrodes (Fig. 4.) mounted one above the
other, giving a total of twenty-two banks of electrodes arranged
in two horizontal rows of eleven each. These banks of electrodes,
each of which consists of 48 mild steel plates, 10" x 16" x 3/16",
^pc^cecj ^" apart, are placed across the tank, the plates being
vertical and parallel to the sides. The 48 plates of each bank
are [electrically connected so that alternate! plates have the same
polarity. The spaces between the banks and the sides of the
tank are blocked up, compelling the sewage to flow between the

Digitized by

Google

164 H. J. M. Creighton and Benj. Franklin. [JFI-

}^'* spaces between the electrodes. There are no partitions
or baffle plates, the sewage flowing straight through the tank from
one end to the other. The electric current passes through the
twenty-two cells in series, but as these are all in the same body
of liquid there is necessarily some leakage of current from one
set of electrodes to another through the liquid, and the electricity
which leaks in this way performs electrolysis less than twenty-
two times.

Fig. 3a.

In each of the ^" spaces between the electrodes, two paddles
or agitators are revolved, being attached to shafts passing through
holes punched in the electrodes to receive them. These paddles are
placed between the electrodes when the banks are assembled, their
hubs being so shaped and interlocked that they remain in position
to receive the shaft and insulate it from the electrodes. An
electric motor drives the paddles at a speed of 20 R.P.M., the
power being transmitted through the double reduction gear box
and the two banks of protected bevel gears shown in Fig. 3a and
Fig. 4. The two shafts for revolving the paddles are, for each two

Digitized by

Google

Aug.,1919] Electrical Treatment of Sewage. 165

banks of electrodes, electrically connected by means of braces in the
outside mechanism for driving them ; each pair is insulated from
the next by a leather coupling. The voltage between two neigh-
boring pairs of shafts is about 6, or about equal to that of two
cells. This necessarily gives rise to internal cross-currents which
reduce the electrolytic action, but this reduction is probably not
large. A more serious result is that those shafts which act as
anodes to this leakage current will become corroded electrolyti-

FlG. 4.

cally. This could be avoided entirely by omitting the connecting
braces, thereby insulating each shaft from all of the others,
leaving only the leakage current which may enter the same shaft,
which is presumably very small, if indeed it exists at all.

As each electrode has an unobstructed area of 120.2 square
inches per side, and as the 48 plates of each bank of electrodes
are electrically connected so that alternate plates have the same
polarity, each bank contains 5649.4 square inches of positive and
negative electrode area respectively. The total positive and nega-
tive electrode area in the electrolytic apparatus, which con-
tains 22 banks of electrodes, is, therefore, 124,286.6 square inches,
respectively. The total number of paddles is 2068.
Vol 188, No. 1 124— 13

Digitized by

Google

i66 H. J. M. Creighton and Benj. Franklin. IJ. fI-

With the arrangement just described, the sewage is brought
into intimate contact with the electrodes, thus enabling the nascent
oxygen and hydrogen to be used eif ectively. In its course through
the tank the sewage flows for 14 feet 8 inches between electrodes,
and for 11 feet 10 inches through the spaces at the ends, in the
middle and through the spaces between the banks of electrodes,
which latter spaces are 7 inches. Hence during about 55 per
cent, of the time or distance of flow through the tank, the sewage
is under electrolytic treatment, and during 45 per cent it is not.

Experiments carried out by the inventor for the purpose of
determining the life of the mild steel plates which constitute
the electrodes, have shown that the total amount of iron removed
from the electrodes by the current amounts to 1.41 pounds per
24 hours, and is not in any way influenced by the volume of sewage
treated. This figure has been substantiated by tests made by the
writers. As each plate weighs 8.33 pounds, and there are 48
plates in each of the 22 banks of electrodes, the total weight of
the electrodes is, therefore, 8796.5 pounds. Assuming that two-
thirds of the metal can be removed from the electrodes without
rendering them useless, it follows that 5864.3 pounds of iron can
pass into solution without destroying the electrodes. On account
of frequent reversal of polarity, the loss of iron is distributed
between all the electrodes. From the figures just given, it is
evident that the life of the electrodes should be about 11.4 years,
and that the electrolytic corrosion of the iron is a negligible factor.
The electrodes of the tank at Easton were examined by the
writers, after having been in use fof many months, and showed
no visual signs of wear, the edges being still sharp.

At this plant provisions are made for using either lump or
hydrated lime. When lump lime is used the lumps are broken
up on a 3-inch grid placed over the crusher, which reduces it
to the size of cracked corn and discharges it into the boot of an
elevator. A spout is provided so that hydrated lime may enter
the elevator directly. The crushed or hydrated lime is elevated
to a divided overhead hopper mounted above the two slaking
tanks (Fig. 5), each of which is 7 feet in diameter and 3 feet high,
only one of which is used at a time. The lime is dischai^ed
from the overhead hopper into either of these slaking tanks at
their sides by adjustable feeding devices which are moimted on
trusses supported by the sides of the tanks, and are actuated by
the same motor that drives the agitator in the bottom of the tank.

Digitized by

Google

Aug., 1919] Electrical Treatment of Sewage. 167

Either city water or, as is generally the case, the effluent
from the process is used for slaking the lime. The effluent
is pumped into the bottom of either of the tanks by a one-inch
centrifugal pump connecting with the observation flume and the
milk of lime is discharged from the top of the tanks through
suitable piping into the spillway of the weir or into the outlet pipe
of the electrolytic apparatus.

The construction of the feeding device is very simple, con-
sisting of a reciprocating link driven by an eccentric, which by

' Fig. 5.

means of pawls and a ratchet actuates the feed worm. The
quantity of lime discharged into the slaking tanks depends upon
the number of revolutions of the feed worm and this may be
controlled by changing the position of the eccentric or by varying
the number of teeth engaged on the ratchet by changing the posir
tion of the pawl arm, permitting a total of 87 adjustments.

It has been mentioned previously that one of the functions
of the lime is to render the electrodes passive, so that they will
not be corroded by electrolytic action. After the electrodes have
become passive, the crystalloids of calcium carbonate produced by
the action of the lime on the sewage begin to accumulate on them.
This increases the power required to rotate the paddles, which

Digitized by

Google —

i68 H. J. M. Creighton and Benj. Franklin. IJ. FI-

is indicated by a watt-meter placed in the circuit of the motor
that drives them. When this motor indicates 2000 watts, the
addition of lime to the spillway of the weir is discontinued and
it is then admitted to the outlet pipe of the electrol3rtic tank.
Under these conditions the acid content of the sewage dissolves
the crystalloid deposit without affecting the production of nascent
hydrogen and oxygen. As soon as the watt-meter reading
becomes normal (1000-1200 watts), the lime is again admitted
to the spillway of the weir and its addition to the outlet pipe
of the electrolytic apparatus discontinued.

The normal operation of this process requires that the effluent
from the electrolytic apparatus shall contain 30 p.p.m. excess
CaO. Should this excess be decreased, the resultant coagulation
is poor, and when greatly increased the coagulation is not
improved, but the crystalloid deposit upon the electrodes forms
very rapidly, necessitating the reversal of the point of lime dosage
at shorter intervals.

During the operation of the electrolytic apparatus, the occlusion
of hydrogen and oxygen by the electrodes causes a consider-
able increase in resistance, and it is therefore necessary at four-
hour intervals to change the polarity of the electrodes by a switch
on the powerboard in order to counteract this phenomenon. This
maintains the electrodes in a passive condition and keeps the
resistance of the apparatus practically constant, while the pro-
duction of nascent hydrogen and oxygen is unimpaired. An
increase in resistance is also occasioned by electrolytic depositions
on the electrodes taking place. This is indicated by a rise in
the voltage of the electrolytic apparatus and a fall in the current
strength. When, therefore, the voltage and the current strength
attain certain values, the direction of the current is reversed
and then these deposits re-dissolve.

The method of operation that has been adopted at Easton
to take care of the wide variations in both the flow and the charac-
ter of the sewage is exceedingly simple and ensures satisfactory
results at all times, but it is much mcrre expensive than would
be the case were the sewage flow equalized, as more lime is
required continuously to take care of the variations of the sewage.

The total consumption of energy chargeable directly to the
process is that used for electrolysis, that for driving the paddles,
that for pumping a portion of the effluent into the lime-mixing
tank, and that for driving the stirrer and feeder of this tank.

Digitized by

Google

Aug., 1919] Electrical Treatment of Sewage. 169

All this energy, and none other, is measured in a* sealed General
Electric Company's kilowatt-hour meter attached directly to a
three-phase, 60-cycle, 220-volt alternating current. Part of the
current which passes through this meter operates a motor genera-
tor, which furnishes the direct current for electrolysis. That
portion of the total power which as direct ciu"rent passes through
the clectrol3rtic tank, is read separately on a voltmeter and amme-
ter; that portion which is used for driving the paddles located
between the electrodes is measured on a separate indicating
wattmeter.

The voltage of the individual cells ranges from 2.5 to 3.7
volts, averaging about 2.82 volts, while a current of 34 amperes
is flowing.

in. BZPBRIMBKTAL RESULTS.

In order to determine the diicacy of the Landreth Direct
Oxidation Process, an investigation was carried out at the demon-
stration plant at Easton, on February i8th, 19th, 20th and 21st,
during which time the plant was operated under the direction and
constant supervision of one of the writers and his two assist-
ants, Messrs. O. R. Quayle and J. D. Ballard. Composite
samples of both the raw sewage and the effluent were pre-
pared from half -hour samples of these liquids, and the chlorine,
nitrite, nitrate, required oxygen and dissolved oxygen were
determined in the former samples immediately after obtaining
them. Portions of these composite samples were sent at once to
Mr. James DeLong, at Lafayette College, Easton, Pa., who
made determinations of albuminoid and free ammonia. The
bacteria content was determined by Dr. E. Q. St. John, of Phila-
delphia, in samples of both the raw sewage and the effluent taken
every two and one-half hours, or oftener, during the runs. The
bacteria samples were kept on ice and sent to Philadelphia daily
by special messenger.

One litre of each composite sample of raw sewage and of
dfluent was placed in bottles of that volume, with only a small
air space at the top to allow for expansion, and sent to the
Chemical Laboratories of .Swarthmore College, where the dis-
solved oxygen remaining in the samples at the end of five days
and the suspended matter were determined.

Owing to the fact that the composition of the raw sewage
delivered to the plant was liable to vary greatly from moment to
moment, it was necessary, in order that the influence of the elec-

Digitized by

Google

170 H. J. M. Creighton and Benj. Franklin. IJ.FI-

trolytic-lime treatment might be ascertained, to determine the time
required for the sewage to pass from the point where the samples
of raw sewage were collected, to that point where the samples
of effltuent were taken. This was accomplished by adding a suit-
able dye to the sewage at the first point and noting the time
required for the color to appear at the second point. From the
spillway of the weir, and from the entrance to the grit chamber,
points at which samples of raw sewage were collected, 95 seconds,
and 3 minutes, respectively, were required by the sewage to pass
to the observation flume where the samples of effluent were takea
Therefore, by allowing this time to elapse between taking the
samples of raw sewage and effluent, there were obtained corre-
sponding samples. It might be of interest to mention that several
of the dyes employed, as well as phenolphthalein, were decolorized
while passing through the electrolytic apparatus. The individual
samples of both raw sewage and effluent, of which the respective
composite samples were composed, were made by dipping up
three portions of 250 cc, thirty seconds elasping between each dip.
During the tests covered by analyses i to 9 inclusive, the
hydrated lime was fed into the mixing vat at the rate of 856.4
pounds per 24 hours, or an equivalent of 672 pounds 90 per cent.
CaO lump lime. The milk of lime so formed was added to
the raw sewage at the spillway of the weir at the rate of 30
gallons per minute. The lime was found on analysis to contain :

Percent.

CaO 71-36

Fe,03+Al^ 2.47

CI as

CO, 0.0

The purification process, operated in the manner recom-
mended by the inventor (i.e., the use of electricity and lime), was
tested over a period of 35.5 hours, this period being made up
of a run of 14.5 consecutive hours on February i8th, during
which three composite samples for chemical analysis and six
samples for bacteriological examination were taken; and a run of
10 and another of 3 consecutive hours on February 19, covered by
three composite samples for chemical analysis and nine samples
for bacteriological examination; and a run of 5 and another
of 3 consecutive hours on February 19th. covered by two com-
posite samples for chemical analysis and 6 samples for bacterio-
logical examination. During these three days the weather was
cold and fine.

Digitized by

Google

Aug.. 1919-] Electrical Treatment of Sewage.

171

0--

;

cnS:

C
rv

. —

^Q-

— --.

0--

o.--r

«■»

(7)

—

coS:

3""

«0

-J-'.

—

•<

>fc

JC--4J

r>-

^f?

...i

<VJ

--^

r--

•

i:::;;;^

^ v

U)- -^

u---

. —

u--«

<£>

o-.]

—

<oE

} ,

)

-c

<VJ

(D *

' —

;

<■■-

"--

(0^

MO-

)O0

1-
00

lOTJ

Digitized by

Google

172 H. J. M. Creighton and Benj. Franklin. IJFI.

•^^ =5; ^:=

~^ I

s ' '4.

1 > V

> ( 1

^ 3^

^- — ^

-"' ^ ^^4_

y *^\-'-'

C *c" >

-7 -r^ — 1 1 -

^^H — <L '.'

? \ "'

- %-.>

-^ ¥ i: ■;&:

>: i 2

^ ,> N

^/^Su^

,. ^' ,„ ^^"-

'i 1 "

'■ 2<| . \...' !;

Ts^>| fer^--7i:

--^•^ \"3 '^

5^- s^?

——5 — ^|e—

U ^rf 1 kr Nv

5 I 2

i^ =^t i^

= ==£= =i==|=

o o
h- IT)

<0 Q.

E
*0<

<^E

<d5

Digitized by

Google

Aug., 1919] Electrical Treatment of Sewage. 173

Variations in the flow of sewage during these periods are
shown by the curves in Fig. 6. In this figure are indicated
by the numerals, i to 8, the periods covered by the composite
samples taken for chemical analysis, and by the letters, a to u,
the times at which samples were taken for bacteriological
examination.

In Fig. 7 are shown graphically the variations in the volt-
meter, ammeter and wattmeter readings. The hours at which the
direction of the current through the electrolysis tank was reversed
arc indicated by the heavy vertical lines. It will be seen that,
for the most part, the current was reversed when the voltage
was high and the amperage low. Further, it will be observed
that the form of the voltage and amperage curves on February
20th is quite different from those for the two preceding days, a
high voltage being necessary to maintain the normal operating
current. On this day a considerable quantity of grease was
observed in the effluent. It is believed that the presence of the
grease considerably increased the electrical resistance of the
sewage.

In Table I are given the analytical data and the average of
the bacteriological data obtained for the periods indicated, for
both the raw sewage and for the effluent.

As it had been suggested that the efficiency of the process
was due primarily to the action of the lime which was thoroughly
mixed with the sewage in the electrolytic apparatus, electricity
playing but a minor part, the examination at Easton included
an investigation of the efficacy of the apparatus in the purification
of sewage, ( i ) when the raw sewage, after having been mixed
with the usual quantity of lime suspension, was passed through
the tank and subjected to thorough mixing by the paddles, with-
out electricity; and (2) when the raw sewage to which no lime
had been added was subjected to the action of the electric current
in the tank. As the inventor was of the opinion that the electrode
would be damaged by allowing the lime-containing sewage to flow
through it in the alienee of the electric current, or by operating
it with electricity in the absence of lime, for periods longer than
one hour, the tests just mentioned each extended over a period
of sixty minutes. During these two periods composite samples
were prepared by taking portions of both the raw sewage and
the effluent at intervals of five minutes, while for bacteriological
examination samples were taken every ten minutes during the

Digitized by

Google

174 H. J. M. Creighton and Benj. Franklin. [JFI-

§s-s

•o

H-

"S «1" c

2
a,

o
d

o
to

^00

« (OIOOO

o o io\o o r^oo « mm

g.oooo«2-g.o«g.

^>o

o m

00 O ....

ch S 3" 5->o : : «o N

N.d d d d • • • • d^>d

4vd

>g^^6d6d2>2-g>«S5a

•om d ^

lOOO •

4 •-•' d 6 d d r^ ^ d^ m ^ *^

00 lO

d »o

8 to into
d d d d d d

8"^

«oio>o o
»o>o oo^^ooa^^^»^ a^^o
d ^ d d d d r^ to N 00* mI to

^lo o ^

OvO

oo>q *9^^ w "?
looo vd «o d «o

NO lO '^

mt>«o o o o

torn

Mivq
d lo

gsOO

I o O >o r^M NO

«otoo o o o r^iof^vo "^ to

«ONO "^ •-• W N lO ^

00 O^ 1^ o

00 to Mr*
to f^ 6^

p^Up^Mp<Up<»P!^Cz^P!^» Pi^ p<H

uaSoi^it^

uaSAxQ Pd^IoifiG

Digitized by

Google

Aug., 1919] Electrical Treatment of Sewage.

175

J2 o 00 w —

w ^ o too o

•Ss

10 NO

Sovoo o <oo O 5 M

00
00

« 9 t
f^ o

{>5;SS>° 8 8 8)0*^

00 CO^.

^ NO

a^^«.

«o 10

J;^ X lOiO

o^ S 5.S S S o

M >0

S"?^&|8,8 8v»^

1-4 ^ 1-4

»peiUp<pqp<pi^p!^pq

c8 o rt a

^5|

9 2 0)

Ih <-< ^

8.as

8 o^^b*^ . g o 10 o j; a^ a© wji^^Efe^ct bfl
H H H « oJ^z: < 0. MM

Bua^oBg

Digitized by

Google

176 H. J. M. Creighton and Benj. Franklin. [JFI-

hour. These tests were made on February 21st, on which day
there was a light fall of snow which melted rapidly. The varia-
tions in the sewage flow during the two tests are shown graphi-
cally in Fig. 8, and the electrical data are shown in Fig. 9. The
results of the chemical analyses and the bacteriological examina-
tion which cover the two tests are given in Table II.

Fig. 8.

<
o
o
o
o
o
o

FEB.21

— '

—

■^

VWX Y ZAA BBccoDKrreo

,11111 1 1 1 1 -1 1

•/

•\J

HOUR
FlG. 9.

1
PM

1.4

—

rs 1

PAD

■)! F

.«»

1.2

II n>

VAT

OLl^S

—

kMP

ERE

— ^

—»-*

^.^

10 11 12 1

AM HOUR PM

IV. DISCUSSXOK OF RESULTS.

Various standards for the purity of sewage effluents have
been formulated from time to time. Kinnicutt, Winslow and
Pratt state in their book just published that " in the United States
the usual requirement is that the effluent must be non-putrescible.
or must contain only that amount of organic matter which, when

Digitized by

Google

Aug., 1919.] Electrical Treatment of Sewage.

177

li
If

N
N

o
6 6

1 I

fO o
N o

I T

c,_; c

« c . o «

+ I

d d

d
I

o o
00 ^ q o t>. o io^wt>.ioo Ovo o ^
d « d d d ^. f^ ^ CI « ^06 •4- in 6 6

«5r^O i>.ioO

^M OvC» lOi-"

00*

00 ff) r^

O >^ M

+ + I

T ffclf f f f

10 to

8 8

d d

r- S*5

+ I + +

10 5^

O 10 lO

t>.q q q>c>vq>qoqoq ^\o 0^00 o^ o q

t>» d dddd»oiof^f^ ^>d ^ r^ d d
nooo m »-i m moo t^

o^ 0. ^ o o '^

S" f^ W 00" Q »^

p<»0[^»p<»p<»0[^»0t^»p<pqp^pq f^»p^»p<»

J2J 2 £

f*5

Mi4

-4^

•.rS

S13 U9S0Jl(l|)4

"a
6

n ♦*

■ I"

■m

Digitized by

Google —

178 H. J. M. Creighton AND Benj. Franklin. [JFI-

the eflauent is emptied into a stream, can be oxidized by the
oxygen contained in the water at the time of the minimum flow;
and that it must be sufficiently freed from suspended solids to
avoid the accumulation of sludge banks or the creation of surface
conditions offensive to sight and smell. In certain cases, as
when the effluent is emptied into a stream in the near neighborhood
of a point at which water is taken for domestic use, or is emptied
into salt water in the neighborhood of shellfish layings, the
effluent must also be freed from the great majority of tiiie sewage
bacteria."

" The International Boundary Commission, as a result of its
study of pollution in the Great Lakes, suggested that the raw
water to be treated by a purification plant should contain not
over 500 B. colt per ido c.c. as an annual average, and should
not show B, colt in more than half of a series of o.i c.c. samples
if satisfactory results are to be secured. According to this stand-
ard it would naturally be required that sewage treatment should
be carried far enough so that after dilution has taken place the
effluent discharged shall not produce, at any neighboring water
works intake, a raw water of greater bacterial impurity than that
specified above. The requirement of the Commission is perhaps
an unduly strict one since many filtration plants (such as that 6f
Cincinnati) are treating waters much more polluted than this
with success."

" Authorities in America generally consider that more valu-
able information can be obtained from the study of the nitrogen
data than from any of the other factors, while in England and
Germany greater importance is placed on the oxygen consumed.
If total carbon could be determined easily, this determination
would probably be most valuable. Oxygen consumed, however,
does not bear a constant relation to total carbon and is open
to the same objections as albuminoid nitrogen."

" The latest and most authoritative standard of this kind is
the one formulated by the Royal Commission on Sewage Dis^sal
in its Eighth Report (R.S.C., 1912). It provides as a general
standard that a sewage effluent must not contain as discharged
more than 30 parts per million of suspended matter and must
not take up more than 30 parts per million of dissolved oxygen
in 5 days at 18.3° C. If the volume of diluting water available
is 150-300 times the volume of the effluent the dissolved oxygen

Digitized by

Google

Aug., 1919.] Electrical Treatment of Sewage.

179

test may be omitted and 60 parts of suspended solids would be
permissible; if the volume of diluting water is 300-500 times
the volume of the effluent the limit of suspended solids may be
raised to 150 parts ; while if the diluting volume is 500 times that
of the effluent all standards might be dispensed with provided
necessary screen^ and detritus tanks were provided."

In Table III are compared the changes brought about in raw
sewage by:

1. Electrolytic-lime treatment with the Landreth apparatus;

2. Lime alone with the Landreth apparatus;

3. Electricity alone with the Landreth apparatus.

Table IIL
Change Produced in Sewage by the Landreth Apparatus Operated With:

Lime and Electricity

Lime alone

Electricity alone

P. P. M.

Per cent.

P. P. M.

Per cent.

P. P. M

Per cent.

Chlorine

+ 1.2

+ 1.9

+58.3
+23.6
-18.3

+ 12.3
- 0.005
+ 0.005
+ 0.2

+ 18.2

-I-I.6

4- 2.2

Nitrite

-f 0.014
+ 0.13
- 3.3

— lO.O

— O.OI

— 20.0

Nitrate

+ 0.8

-0.15
+0.9

— 20.0

Free ammonia.. .

+ 1.3

+ 6.6

Album. NH,

- 3.6

— I2.I

- 0.4

- 1.7

-0.5

- 2.3

Required oxygen.

-13.0

-20.5

- 7.7

- 8.9

-6.5

-lO.O

Dissolved Oi

+ 1.78

+40.9

- 0.93

-19.1

+1.61

+40.1

Dissolved . ..R«

4.17

95-9

4.85

99.4

3.93

98.0

Oi absorbed in 5

days E-

0.77

12.6

3.82

96.7

5.17

92.0

[Total count

'J3

at 37" C,

per c. c

-343,200

-92.7

- 373,000

-82.4

-165,000

-37.8

■«

Total count

at 20" C,

percc....

-688,000

-92.2

-1,074.000

-90.1

-635,000

-70.0

B. coh at

37" C. per

c. c

- 77.880

-99.85

- 96,300

-92.3

-45,000

-81.8

From a comparison of the results recorded in Table III, it
will be observed that with electrolytic-lime treatment the quanti-
ties of nitrite and nitrate in the sewage are increased, while with
lime alone and with electricity alone a material decrease or but
a slight increase is effected. With the electrolytic-lime treatment
there is a marked decrease in free ammonia and albuminoid
ammonia, whereas with the lime or with the electrical treatment

Digitized by

Google

i8o H. J. M. Creighton and Benj. Franklin. [J- F- 1-

there is a small decrease in albuminoid ammonia, and an increase
in free ammonia. The required oxygen is decreased by all three
treatments, but that effected by the electrolytic-lime treatment
is approximately double that brought about by either of the other
methods. Due to the prodi^ction of oxygen by the electric cur-
rent, an increase in dissolved oxygen of about 40 per cent, is
effected by the electrolytic-lime treatment and by the purely elec-
trical treatment; while with lime alone a decrease of 19 per cent,
in dissolved oxygen occurs.

The amount of the dissolved oxygen absorbed by the effluent
in five days at a temperature of 10° C. to 15° C, affords very
important information regarding the efficiency of the three
methods of treatment. Indeed this test is regarded by many
authorities as one of the most important standards for deter-
mining the purity of an effluent. The results recorded in Table III
show that while practically all of the dissolved oxygen in the raw
sewage is absorbed during the five-day period, that in the effluent
produced by the electrolytic-lime treatment is reduced only 0.77
part per million, or 12.6 per cent., a figure which lies far below
the limit allowed by the Royal Sewage Commission. On the
other hand, nearly all of the dissolved oxygen in the effluents
produced by the lime treatment and by the electrical treatment is
absorbed in the five-day period, showing that by these methods the
unstable organic matter in the sewage was but partially oxidized.

It will be observed that electrolytic-lime treatment brings
about a reduction of over 92 per cent, in the total bacteria count,
while the lime treatment effects a reduction of 82 per cent, at
37° C. and 90 per cent, at 20° C, and the electrical treatment
produces a reduction of only 38 per cent, at the higher tempera-
ture and 70 per cent, at th^ lower temperature. The reduction
in B, coli per c.c. amounts to 99.85 per cent, with the electrolytic-
lime treatment, and to 92.3 per cent, and 81.8 per cent., respec-
tively, with the lime treatment and with the electrical treatment.

It may be of interest to mention that the effluents produced
by the different treatments were examined after having been
kept in stoppered bottles for five weeks. Those obtained in runs
I to 8 (electrolytic-lime treatment) had little or no odor; that
obtained in run 9 (lime treatment only) had a very disagreeable
odor, while that obtained in run 10 (electrical treatment only)
smelled strongly of hydrogen sulphide, and had turned black

Digitized by

Google

Aug., 1919.] Electrical Treatment of Sewage. 181

owing to the conversion of the iron dissolved from the electrodes
into iron sulphide.

It is evident from the data recorded in Table III that not
only is an highly satisfactory effluent produced by the Direct
Oxidation Process, but that the combination of lime and elec-
tricity, when employed in the apparatus described, is much more
effective in purifying sewage than either lime alone or electricity
alone when employed with the same apparatus.

In judging the efficacy of the Direct Oxidation Process, it
must be remembered that the data given in the preceding tables
refer to the effluent as it comes from the electrolytic tank, and that
by the conjunctive use of a sedimentation basin the suspended
solids, consisting largely of lime, could be considerably reduced.
This reduction would also be attended by a further decrease in
albuminoid ammonia, required oxygen and the bacteria.

In order that the results obtained with the Direct Oxidation
Process of sewage treatment may be compared with those obtained
with other methods, analytical and bacteriological data relating
to a number of methods are given in Tables IV and V.

v. COSTS AND COMPARISONS.

After a careful study of 16 different plants for sewage treat-
ment in this country, varying in cost from $40,000 to $9,000,000,
we still find it extremely difficult to make a comparison in cost
either of construction or of operation of the electrolytic process
of sewage treatment with other methods, since the conditions
affecting the installation of a sewage treatment system vary greatly
and frequently involve factors which in the aggregate are more
costly than the construction of the plant.

Take, for instance, the selection of a site for a treatment
plant. It must be sufficiently remote to avoid offense ; its elevation
should be low enough to receive the sewage by gravity or at least
to minimize the cost of pumping; and it ought also to be reason-
ably close to a stream furnishing a proper outlet for the effluent.
To meet these general conditions, heavy costs may be incurred
in the purchase of land suitable for the purpose and frequently
tracts thus acquired must be largely in excess of the actual needs
of the plant so as to avoid the depreciation of adjacent land
values. The cost also may be increased by the construction of
long and expensive trunk line sewers; the construction of col-
lecting basins and pumping stations for the purpose of lifting

Vol. 188, No. 1 124— 14

Digitized by

Google

i82 H. J. M. Creighton and Benj. Franklin. [JFI-

.s
3
S

i ii i ri

1? §5
Is. 1^

row ^« ^

d d d d

I.
P

: o^

"^^O

t^t^

• r»5

d «

o «

d«

00 Ch

00 00

« t^

fOt^

t'^'

fooo

s«

ftfO

?iP;

855

S»

00 o

<><>

"*fO

« Ch

!>.

00 >o

*- O^

t^rO

4ff>

>0 ro

l>.fO

>o «

r^fO

00 o

yO t%

5* : : 5?2 is 5 : *"* : : ?*

Digitized by

Google

^ng., 1919.] Electrical Treatment of Sewage. 183

^e sewage across divides from one drainage area into another,
^ tKat treatment can be obtained at a central plant; and the
Pt'operty damages which in some cities result from the widening
^' streets and the changes of grades made necessary to accom-
^^^a.te concentrated drainage.

Tablb V.

Bacteria ReducHon by Various Methods for Treating Sewage,

Intermittent Filtration at Brockton, Mass.

Kinnicutt, Winslow and Pratt.
jj Total count B. coli per

i^"^fc^ per C.C. ftt ao c .c.

_^*wagc 3,150,000 150,000

^^s

^\%^^t A 1,900 400

"^?^t B 6,300 15

^^^nt D 125 o

^^ABVient E 1,400 5

^ffiuent P 2,000 I

Results of Experiments at Lawrence, Mass.

Metcalf and Eddy. p^, ^^^^ bacteria

Regular sewage, as received from force main at removed

station 2,095,600

Settled sewa£[e 1,386,300 33.8o

Effluent, stramer E (12'' depth buckwheat coal, rate

800,000 gals, per acre per day) 874,200 58.50

^resh sewage (from toilet room at station) 3,241,600

Effluent, Imhoff tank 1,700,300 46.60

Effluent, sand filters 2,565 99.88

Effluent, contact filters 1,105,600 47.20

Effluent, trickling filters 254,500 81.70

While it is true that in the electrolytic process described in
this paper, a number of units are eliminated which are required
in ordinary treatment systems, yet in a small electrolytic plant
this saving is more than offset by the cost of the protective
building which is necessary. In addition there is the constant
employment of skilled labor which such a plant requires. Where
'f is possible to combine a water pumping station, an electric
hghting plant, and a Landreth Direct Oxidation sewage treatment
V^atit under one roof, the proportional cost of the protective
structure, as well as operation, is reduced, making it a probable
aavaata^e to employ this method. When this cannot be done,
"^^ L-3.n<ireth Direct Oxidation process is not in our judgment

^^i* experience at the Landreth Dinedki OdcideUlionT^plant in

Digitized by

Google

184 H. J. M. Creighton and Benj. Franklin. [J- F- I.

Easton fully justifies the statement that a plant of this type can
be installed and operated in any densely populated section without
detection by the public.

The importance of this advantage is evident when it is con-
sidered that an inexpensive property of a few thousand square
feet conveniently situated near outlets of main sewers is all that
is required for this electrolytic process compared with the large
areas at a distant point demanded by ordinary methods of sewage
disposal.

Table VI.

Comparison of Cost of Operation Between 2,000,000 Gallon Plant and

10,000,000 Gallon Plant.

Capacity 2,000,000 gallons per day.

Population 20,000.

The operation cost is based upon the following daily items :

1600 lbs. 90 per cent, lime per day at $6 per ton $5.33

Current, 282 k.w. hrs. per day at 2 cents 5.64

Heat and light per day 2.00

, Renewals 2.00

Maintenance and repairs 1.00

Labor:

3 men — 8 hr. shifts, at $5, $4, $4.

I laborer at $3 16.00

Total $31.97

This is 58 cents per capita per year for operation, of which about
51 per cent, is for labor alone.

Capacity 10,000,000 gallons per day.

Population 100,000.

The operation cost is based upon the following daily items :

8000 lbs. 90 per cent, lime per day at $6 per ton $26.75

Current, 1410 k.w. hrs. per day at 2 cents 28.00

Heat and light per day (estimated) . . . .' 2.00

Renewals 10.00

Maintenance and repairs 6.00

Labor:

I superintendent 5.00

3 operators at $4 12.00

I laborer 3.00

fe2.75

This is 34 cents per capita per year for operation, of which about 22
per cent, is for labor.

Digitized by

Google

Aug., 1919] Electrical Treatment of Sewage.

18:

•S

_ c.
IIS

£ ^^5 M

S ffiW

nO 00 NO

Qn fJOO

00 r^fOON

r^ ro ^00

^ r^vo

> Q 1^ »O00 C*

* 00 On lOt^ a^

00 w

to NO

5 o f

888 88 8 888 8 888

;8;

2"||

1000

00 fO

►^06 lO
1^00^ O^

% o

-S o 5J 'd

•3.0.?.

-J

2.S
*5 o

Digitized by

Google

i86

H. J. M. Creighton and Benj. Franklin. IJ-F-I-

a
.S

^4»4^4 ^4^4^4^4*14 »4 >ii4»4 N4 »4

^ ^ ^ ^ ^ ^ ^ O^ ^ 9^ Ch 9^ 9^

PU Pk Oi Pk C

^>»^ ^-^^i

00 00 t» M 00 vo NO t^oo o o lo •-• 9^
r>. ^O «^ ^^^'^'l' *9 900 r>. cK

10 OS

00 t^O

S 8 88 888 8% 8 8 8 8 8

>8 880^ 8808^ 8 8^ IN; 00^ o^

00 vo ^vo 1000 c^ cT ^ pT o »^ r6 ^

10 « ^^ »N i>.^oo a» vo ^«5 •- *-

o' * r"*5

I US

11 6 i-^

" §1 1 ■§

Digitized by

Google

Aug., 1919] Electrical Treatment of Sewage. 187

In the operation of this electrolytic process it is imperative
to have skilled labor in constant attendance, although the duties
imposed upon it are light. However, in this process the number
of units can be largely increased without any appreciable increase
in the amount of labor necessary to operate the enlarged plant.
This is illustrated by the data contained in Table VI showing
comparisons between the operating costs of 2,000,000 gallon and
10,000,000 gallon plants.

In Table VII is given the cost of construction of various
sewage disposal plants in the United States. It has not been
possible in this table to indicate in every case the actual cost of
the disposal plant alone, eliminating property values, trunk lines,
costs, etc., and on that account the per capita costs show such great
variations. It is evident, however, that the per capita cost of the
construction of a Direct Oxidation plant compares favorably
with that of any other process.

The data in Table VIII indicate the actual cost of operation
per capita of a number of sewage disposal plants in the United
States with the additional costs for interest and depreciation:
An examination of this table indicates that the economy resulting
from the use of the Landreth Direct Oxidation process is effected
largely through a saving in the cost of construction.

Fire Engines and the Essentials of Fire Fighting. Charles
H. Fox. (The American Society of Mechanical Engineers, Spring
Meeting, June, 1919.) — Steam pqwer was not successfully applied
to fire engines until the beginning of the year 1853. Up to that time
the so-called " hand engines " were used exclusively and it should
also be understood that at that time the present-day system of water-
works, was still in its infancy and, therefore, the chief dependence
for a supply of water for fire-extinguishing purposes was upon
methods of storage in vogue before water mains came into gen-
eral use.

The conventional hand fire engine of that day comprised a rec-
tangular wooden box suitably mounted on four low wheels. Pumps,
of the piston type, were housed within and firmly fixed to the floor
of the box ; working levers were provided and motion was imparted
to the pistons by a host of firemen lined up on opposite sides of the
apparatus. At this early period fire hose was not plentiful, the best
was crudely made up of leather, and the pumps were, therefore,
placed close to the scene of the fire. Water, largely conveyed by a

Digitized by

Google

1 88 Current Topics. [J. F.I.

hand-to-hand passing of fire-pails, was poured into the engine trough,
where it was picked up by the pumps and forced through the leading
hose and onward to be thrown on the fire. Somewhat later it be-
came customary to equip these hand engines with a non-collapsible
suction hose, so that water could be drawn directly from cisterns or
wells, but the wooden tub or reservoir always remained a character-
istic feature of these old-time machines.

Early in January, 1853, Mr. A. B. Latta successfully tested his
new steam-driven fire engine. Mr. Latta was a citizen of Cin-
cinnati and although his pioneer effort resulted in the production
of an extremely heavy machine, the engine was purchased by the
city and known as the Joe Ross. The first steamer marked the
beginning of a new epoch in fire fighting.

Latta's second steam fire engine was built and installed in the
year 1853. The purchase of this machine was made possible by
ix)pular subscription and the engine was named and long known
in Cincinnati as the Citizens' Gift.

When fire must be fought, fire streams can be effective only
when the water is expelled from the nozzlle at an appropriate speed.
In other words, unless enough of the initial pressure available for
starting the flow through the hose survives at a point immediately
back of the nozzle orifice, the resulting jet will not measure up to its
rnission. The characteristics of a fire stream — good, bad, or indiffer-
ent — are directly dependent upon the velocity of the jet and obvi-
ously the velocity is proportionate to the surviving pressure just
mentioned. For the best results the flow may be too slow, while, on
the other hand, disappointment will fallow when the velocity of
discharge goes beyond what might be termed the maximum economi-
cal limits of nozzle pressure.

The function of a fire engine is either to draw water from any
basin or other conveniently located source or, when fire hydrants
are available, to make up the pressure, which is seldom high enough
in ordinary water mains to serve for effective fire service. In
fighting fire, it is not uncommon to elevate the nozzle far above the
source of the water supply. This procedure, of course, involves loss
of forcing pressure, which is in proportion to the static head of the
column. The greatest power-absorbing medium between the source
of supply and the point of discharge is the fire hose. In may also be
said that here is involved the point which is least understood in the
subject of hydraulics as applied to fire-fighting practice.

Digitized by

Google

SOME REMARKS CONCERNINQ THE HEAT TREAT-
MENT OF STEEL AND THEIR APPLICATION TO THE
TREATMENT OF STEELS USED FOR AIRPLANE
MOTORS.* ^

ALBERT SAUVEUR, S.B.

Professor of Metallurgy and Metallography. Harvard University.
Recently Director of Metallurgy in the Air Service, A. E. F.

Ix heat treating rolled or forged steel we seek generally:

1. To increase its softness, that it may be more readily
machined ;

2. To make it strong, that it may resist successfully the
stresses to which it will be subjected in use ;

3. To make it hard, that it may resist wear or acquire cutting
properties.

The corresponding heat treatments may be therefore described
respectively as :

(a) Softening Treatment,

(b) Strengthening Treatment,

The Softening Treatment, which usually consists in cooling
the metal slowly from a temperature exceeding its critical range,
generally imparts to it its maximum ductility but materially
reduces its strength (and elastic limit).

It is also highly beneficial in removing the strains resulting
from the working of the metal. These strains are the more serious
and detrimental the lower the temperature at which the metal
was worked. If it has been cold worked, the necessity of remov-
ing them becomes imperative, as a strained metal is a dangerous
one, inclined to be brittle and having reduced resistance to shock
and to fatigue stresses.

The Strengthening Treatment implying, as it generally does,
a rapid cooling from a temperature but slightly above the critical
range of the metal, is not as effective as the softening treatment
in removing working strains. It follows from these considera-

♦ Communicated by the Author.

*A few copies of these remarks were printed for private circulation in
February, 1918, as Bulletin M 3, " Notes on the Metallurgy of Aviation," by
the Technical Section, U. S. Air Service, American Expeditionary Forces.

189

Digitized by

Google _

190 Albert Sauveuu. I J »• i

tions that it is often advisable to subject to a softening treatment
certain steel objects already soft enough to be readily machined
or which are to be subjected to a strengthening treatment, for the
purpose of removing thoroughly the objectionable strains created
by the working operation.

The softening treatment should be logically applied after roll-
ing or forging but before machining.

The strengthening treatment consists usually in cooling rapidly
through the critical range and may be followed, as later explained,
by a second heating below that range.

Roughly speaking, the strength imparted will be the greater,
the quicker the cooling through the range. Increased strength
moreover generally implies increased elastic limit, a property
which is in reality of greater moment than mere tenacity, for,
obviously, it is not intended that steel parts should ever be
strained above their elastic limit, that is, until permanent distortion
actually occurs.

The strengthening treatment, on the other hand, generally
decreases the ductility of the metal and may result in actual
brittleness. Broadly stated, the greater the increase of strength,
the greater generally the decrease of ductility, that is, the greater
the danger of producing a brittle metal; hence the necessity,
in most cases, of being satisfied with such strengthening treat-
ment as will yield, not maximum strength, but such strength
as can be combined with the amount of ductility necessary for
safety, that is, to guard us against sudden rupture under shock.
If, for instance, the cooling through the range has been so rapid
as to yield very great strength but very little ductility, a second
treatment will be required in order to increase the ductility, while
necessarily decreasing the strength.

The rapid cooling through the range which the strengthening
treatment generally implies is, moreover, beneficial in destroying,
in part at least, the structural orientation generally imparted to
steel by work. An objectionable effect of this orientation is to
cause the metal to acquire physical properties when tested in the
direction of the work markedly different from those it possesses
when tested at right angle to that direction. In the former case,
for instance, the ductility as measured by the elongation is, as a
rule, considerably greater. This implies a lack of physical or
structural homogeneity obviously undesirable.

Again, the strengthening treatment generally increases in a

Digitized by

Google

Aug., igip] The Heat Treatment of Steel. 191

marked degree the hardness of the metal, and hence, imparts
to the treated parts greater resistance to wear. Great softness
then, cannot be generally combined with great strength, nor great
strength with much ductility. Softening and strengthening treat-
ments must necessarily be distinct and generally of opposite nature,
the former implying slow cooling through the critical range, the
latter a more rapid cooling. Moreover, the maximum strength
the metal is capable of acquiring can seldom be utilized because
of the lack of ductility, if not actual brittleness, which accom-
panies it.

The strengthening operation must be so conducted as to yield
such combination of strength and elastic limit with ductility, as
will meet the requirements of the case.

The Hardening Treatment, like the strengthening treatment,
consists in cooling rapidly through the critical range.
. In hardening steel, however, the primary requirement is to
prpduce very great hardness, while overlooking the decrease of
ductility implied. Indeed, as a rule, we use all possible means
to hasten the cooling because of the greater hardness resulting.

Even when implements are to be hardened and thereby
deprived of much of their ductility, a softening treatment pre-
ceding the hardening treatment may often be applied with bene-
ficial results because by more thoroughly removing the forging
or rolling strains it will diminish the danger of cracks occurring
during the quenching in the subsequent hardening treatment.

The rational methods of conducting these three treatments may
now be briefly described.

A. SOFTENING TRBATXBNT.

Purpose, — To soften the metal in order to facilitate machin-
ing ; also to remove the strains produced by forging or rolling.

When to Apply. — After forging or rolling, but before
machining.

Description, — (a) Heating the steel to 900° C. (1652° F.),
maintaining that temperature for 30 minutes or more, cooling
slowly, for instance with the furnace in which the steel was
heated. (6) Heating to some 600-675° C. (1112-1247° F.)
for several hours, cooling very slowly, (c) Heating to some 800-
850° C. (1472-1562° F.), quenching in oil, then treatment &.

Treatments (6) and (c) are applicable to steels containing
0.8 per cent, carbon or more, and to some alloy steels which are
not readily softened by treatment (a).

Digitized by

Google

192 Albert Sauveur. IJF. I-

B. STREHGTHEKIKG TREATMEKT.

Purpose. — To increase strength and elastic limit at the sacrifice
of some ductility; also to increase hardness, and, in some cases,
resistance to shock and to fatigue stresses and to decrease struc-
tural orientation.

When Applied. — Generally after machining in the case of
machined parts; after forging, rolling or stamping, if the objects
are not to be machined.

Description. — (a) Heating to 50° C. (90° F.) above the
critical range of the steel," cooling freely in air. Steels containing
less than 0.25 per cent, carbon may be quenched in oil, those with
less than 0.15 per cent, carbon in oil or in water. (6) Heating
to 50° C. (90° F.) above the critical range of the steel; quench-
ing in water or oil (the former for low carlx)n steel), re-heating
to 50° C. (90° F.) or more telow the critical range, cooling in
air, oil or w^ater.

The rate of cooling from a temperature inferior to the critical
range does not generally affect the properties of steel very mate-
rially ; at least its tensile properties. The higher the temperature
of the second heating the less tenacious and more ductible the
metal.

Some nickel-chromium steels, however, show very low shock
strength under impact testing after heating to some 600° C.
(1112" F.) followed by slon' cooliny as compared to their shock
strength after quenching from that temperature.

While treatment (a) often yields satisfactory results, treat-
ment (6) affords a means of securing greater strength, as well as
many different combinations of strength and ductility to meet
different requirements. The steels so treated, especially certain
alloy steels, are generally also more resistant to shock and to
fatigue stresses. There is little if any advantage, however, in
applying treatment (&) in preference to treatment (a) to carbon
steels containing less than 0.25 per cent, carbon.

C HARDEKING TREATMENT.

Purpose, — To produce very great hardness while sacrificing
ductility to the point of brittleness.

When Applied. — To finished parts, as a last treatment, or to
be followed by grinding only.

Description. — Heating to 50° C. (90° F.) above the critical

MIeating steel slightly above its critical range refines the structure, heating
it to a much higher temperature coarsens it.

Digitized by

Google

Aug., iQig] The Heat Treatment of Steel. 193

range of the steel, cooling rapidly in water or oil, generally re-heat-
ing to 200-400° C. (392-732° F.), an operation known as tern-,
pering, which is applied in order to remove or decrease the severe
strains created by the sudden cooling while losing but little hard-
ness and to decrease brittleness. The higher the tempering tem-
perature, the greater the softening effect of the operation.

The three basic heat treatments described above are applicable
to alloy steels as well as to carbon steels bearing in mind the
marked influence of some elements on the position of the critical
range. Some special steels, for instance, should be heated, for
the purpose of strengthening or of hardening, to temperatures
considerably lower than those suitable for carbon steel, because
of the lower position of their critical range. The character of
the operation, however, remains the same.

Classification of Steel According to Heat Treatment Required.
— According to the heat treatments required, steels may be
classified as follows:

(i) Steels soft enough to be readily machined and strong
enough for the stresses to which they will be subjected in service.
Heat Treatment Required.^ — None.

(2) Steels soft enough to be readily machined, but lacking
in strength or in hardness. Treatment to be Applied^ — Strength-
ening treatment (a) or {b) generally after machining, and, for
hardness, hardening treatment.

(3) Steels not soft enough to be readily machined but strong
enough for the uses to which they are intended. Treatment to be
Applied, — Softening treatment (a), (fc) or (c) followed, gen-
erally after machining, by strengthening treatment (a) or (&),
because the softening treatment will generally deprive the steel
of much of its strength, which must then be restored.

(4) Steels neither soft enough to be readily machined nor
strong enough to resist stresses in service. Treatment Required.
— Softening treatment (a), (fc) or (c) followed, generally after
machining, by strengthening treatment (a) or (&).

It will be noted that steels of classes 3 and 4 call for similar
treatments.

(5) Steel parts which should be very hard must be treated by

' It is important to remember that! the softening treatment is also bene-
ficial in removing the strains caused by rolling or forging and that for these
reasons it may be applied with good results even to steels soft enough to be
readily machined.

Digitized by

Google

194 Albert Sauveur. [J. F.I.

the hardening treatment unless they already possess great hard-
ness, such as manganese steel and air or self -hardening steels,
which will be considered later.

As already stated, it is beneficial to subject to a preliminary
softening and strains — removing treatment steel parts to be
hardened.

When for economical or other reasons it is advisable to sub-
ject forged or rolled carbon steel to but a single heat treatment,
cooling in air from a temperature of some 800-900° C. ( 1472-
1652° F.), according to its carbon contents, is generally to be
recommended, because such treatment (i) leaves the steel in a
condition generally soft enough to permit its ready machining
(unless it be very high in carbon), (2) removes, in part at least,
the working strains, (3) obliterates, or at least, mitigates, the
structural orientation and (4) yields a fair proportion of the
strength combined with a large proportion of the ductility which
the metal is capable of acquiring.

HEAT TRBATXBHT OF CASE-HARDBKBD PARTS.

Case-hardened parts generally require :

1. A strengthening and toughening treatment for the core
consisting in quenching from 900 to 950° C. (1652-1742° F.)
followed by

2. A refining and hardening treatment of the case consisting
in quenching from a temperature some 50° C. (90° F.) above
the critical range, which for carbon steel would be in the vicinity
of 800° C. (1472° F.). Special steels with lower critical
range should, of course, be quenched from correspondingly lower
temperatures. For nickel and nickel chromium steels, single
quenching from some 800° C. (1472° F.) is often sufficient.
After quenching for hardening the case the parts may be tem-
pered at some 200-300° C. (392-572° F.) in order to diminish
the strains and the brittleness of the case.

There are a few instances of special steels demanding treat-
ments different from those applicable to all other steels. These
exceptions should be briefly mentioned :

Manganese Steel. — A steel very hard and wear-resisting, even
after slow cooling. To make it ductile, however, it should be
heated to 1000° C. (1832° F.) or thereabout and quenched in

Self' or Air-hardening Steels. — These steels betemeintofifte^

r^k Digitized by GoOglC

Aug., 1919] The Heat Treatment of Steel. 195

hard on simple air cooling from a temperature of some 800 to
850° C. (1472-1562° R). They 4o not therefore need any
hardening treatment and they may be softened by softening treat-
ment (ft).

High-speed Steels. — These steels, in order to acquire their
remarkable physical properties, must be heated to a very high
temperature approaching the melting point of the metal and
quickly cooled in air or in oil. They may then be tempered at
a temperature not exceeding generally 600° C. (1112° F.). To
soften these steels, in order to machine them, they may be heated
to 750°-850° C (1382°-! 562° F.) for several hours and very
slowly cooled.

High Nickel Steels. — That is, those containing 25 or more
per cent, nickel, are softened by quenching.

▲PPLICATIOH OF THB FORBGOIHG C0HSIDBRATI0H8 TO THB HBAT TRBAT-
XBHT OF THB STBBLS USBD FOR THB C0H8TRUCTI0H OF AIRPLAVK
MOTORS.

Adopting the classification of the steels used in the construc-
tion of aviation motors, proposed in previous reports (Bulletins
Mi and M4) the heat treatments they should receive may be
inferred from the rules just outlined :

STEEL TYPE I.

Medium-hard carbon steel containing from 0.30 to 0.40
per cent, carbon. In its forged, rolled or stamped condition, this
steel is soft enough to be machined. It may be nevertheless sub-
jected to a softening treatment with beneficial results for the
purpose of removing the working strains as previously explained.

With that end in view, it should be heated to 900° C.
(1652° F.), kept at that temperature for 30 minutes or more,
and cooled slowly. This treatment should be applied logically
before machining.

After machining, and in order to increase their strength and
elastic limit, as well as their resistance to shock, to wear, and to
fatigue stresses, the parts should be subjected to strengthening
treatments (a) or (fc), bearing in mind that treatment (b) will
yield better results than treatment (a) and will make it possible
to obtain various combinations of strength and ductility to meet
various requirements.

For treatment (a) heat to 850° C. (1562° F.) and cool freely

Digitized by

Google

196 Albert Sauveur. [J. F- I.

in air. For treatment (b) heat to 850° C. (1562° F.), quench
in water or oil, reheat to 450-650° C. (842-1202° F.), accord-
ing to requirements, and cool slowly or in water or oil.

STEEL TYPE II.

Low carbon steel suitable for case hardening, containing from
0.05 to 0.15 per cent, carbon. This steel in its forged, or rolled
condition can be very readily machined, but it nevertheless may
be subjected to a softening treatment, in order, as previously
explained, to remove working strains. With that end in view,
the steel should be heated to 950° C. (1742° F.) for 30 minutes,
or more, and cooled slowly. This should logically be done before
machining.

The case-hardened parts should then be reheated to 900° C.
(1652° F.) and quenched in water or oil, in order to strengthen
and toughen the core. They should then be heated to 800° C.
(1472° F.) and again quenched in water or oil, in order to refine
and harden the case.

They may, as a last treatment, be heated in oil to 200-300° C.
(352-572° F.), in order to decrease the strains and brittleness
of the case.

STEEL TYPE III.

Low carbon nickel-chromium steel, suitable for case-hardening,
containing : Carbon not over o. 1 5 per cent. ; nickel not less than
2 per cent. ; chromium not less than 0.50 per cent. ; and total nickel
and chromium between 2.50 and 4 per cent.

While in its forged or rolled condition this steel can be easily
machined, the softening treatment may be applied to remove
working strains. This should be done before machining, by
heating to 900° C. (1652° F.) for 30 minutes or longer, and
cooling slowly.

The case-hardened parts should be :

1. Either heated to 800° C. ( 1472° F. ) and quenched in oil or
water to refine and harden the case, or

2. Heated to 900° C. (1652° F.) and quenched in order to
refine and strengthen the core, followed by heating to 775° C.
(1427° F.) and quenching to refine and harden the case.

After the last quenching the parts may be tempered by heat-
ing in oil at 200° to 300° C. (392-572° F. ) to diminish the strains
and the brittleness of the case.

Digitized by

Google

Aug., 1919] The Heat Treatment of Steel. 197

STEEL TYPE IV.

Medium-hard nickel-chromium steel containing : 0.30 to 0.40
per cent, carbon; 2.50 to 3.50 per cent, nickel; 0.5 to i per cent,
chromium ; 3 to 4 per cent, total nickel and carbon.

This steel can be machined in its forged or rolled condition,
but a softening treatment will increase the ease of machining and
will be beneficial in decreasing the strains caused by work.

For this treatment, which should be logically applied before
machining, the steel should be heated to 850-900° C. (1562 to
1652° F.) for 30 minutes or more, and slowly cooled.

The machined parts should then be subjected to a strengthen-
ing treatment consisting in heating to 800° C. (1472° F.) fol-
lowed by air cooling or preferably to the double treatment con-
sisting in heating to 800° C. (1472'' F.) and quenching in water
or oil, followed by reheating to 400 to 650° C. (752 to 1202° F.)
according to requirements, and quenching in oil or water.

STEEL TYPE V.

Air-hardening nickel-chromium steel, containing: 0.30 to 0.50
per cent, carbon ; 3.00 to 4.50 per cent, nickel ; 0.50 to 2.00 per cent,
chromium ; and total nickel, chromium and carbon, not less than
5 per cent.

In its forged or rolled condition, this steel is difficult to
machine. It should be subjected to softening treatment (ft).

The machined parts should then be either cooled freely in air
from a temperature of 850° C. (1562° F.) or quenched in oil
from 800° C. (1472° F.) and reheated to 300-600'' C. (572-
1112- F.) according to requirements. Air cooling suffices, how-
ever, to impart great hardness and great strength to this steel.

STEEL TYPE VI.

High speed steel, suitable for exhaust valves. To soften this
steel in order to permit a small amount of machining, it may be
heated to 750-850° C. (1382-1562° F.) for several hours and
cooled very slowly.

The valves should then be subjected to the heat treatment
generally applied to high speed steel, namely :

Heating to a temperature of some 1200° C. (2192° F.) and
cooling in air or in oil. This may be followed by reheating to
500-600° C. (932-1112° F.).

Vol. 188, No. 1 124— 15

Digitized by

Google

1 98 Current Topics. IJ- F- 1-

Method of Turning on Steam in Large Linea. (Power, vd. 1,
No. 3, p. 124, July 15, 1919.) — ^Accidents and consequent losses^
both direct, and indirect, due to the failure of steam piping and
fittings while being cut into service when steam is being turned
in, have apparently all been due to expansion strains rather than
pressure strains. The expansion strains which caused the dam-
age were usually different from those which were present after
the line had been heated to full temperature.

A further analysis discloses the fact that the particular form
of expansion causing the trouble has been in most cases due to
the presence of air in the steam line at the time steam was being
turned on. Air, having approximately twice the density of steam,
remains at the bottom of the pipe and prevents the steam from
coming in contact with (and thereby expanding) parts of the
piping. On a straight run of horizontal piping the result has a
tendency to "rainbow" the piping. This has been proved by
actual test. The further result of this action is to put a heavy
compression strain on the upper half of all joints and fittings and
a corresponding tensile strain on the lower half. This trouble
is experienced to a greater extent with large than with small pip-
ing. This may be due either to the pipe being so small that the
air and steam do not remain stratified, or possibly to the g^eat
flexibility of the small piping.

The method of turning on steam, which will prevent trouble
of this kind, is as follows :

All drains and air vents on the line are opened. Steam is
turned into the line very rapidly, the valve being opened one-
fourth to one-half its full opening. This applies not only to low
pressure, but to high pressure as well. This procedure results
in driving the air out of the line very rapidly and allows the
pipe to heat uniformly. To engineers who have been accustomed
to " warming up " slowly, or " soaking " the line, this method
will no doubt seem dangerous, but the results obtained from
close observation and actual test indicate that it is the best that
can be followed.

The same phenomena take place in starting up a steam tur-
bine. In the Parsons type of machine where the blade and clear-
ances are small, the " warming up " method of starting is likely
to cause blade failures, because when a machine is standing still,
the spindle and cylinder " rainbow " in the same direction, but as
soon as the spindle revolves one-half a revolution, the top of the
spindle (then at the bottom), unless the clearances are large,
rubs the bottom of the cylinder. The new method is to open the
throttle quickly until the spindle starts to revolve, after which
the throttle is almost closed again, allowing the turbine to revolve
slowly until the heat is evenly distributed.

Digitized by

Google

GIMBAL STABILIZATION *

V. BUSH, Eiig.D.

Refl«aroh Labormtoriw, American Radio and Reaeareh Corpomtion.
GBHBRAL.

The following is an analysis of the effectiveness of gimbals
of various designs for maintaining a horizontal platform on ship-
board, and of gyroscopic stabilizing of such devices.

Gimbals can never maintain a platform absolutely horizontal,
for there always will be a certain deviation.

The motion of the ship in the waves can affect the gimbals
in three ways, namely by reason of ( i ) horizontal motions im-
pressed upon the support, (2) vertical motions impressed upon
the support, and (3) tipping of the support

If the friction of the gimbals about the pivots is small, as must
always be the case in a good design, the third effect is entirely
negligible. The second effect comes in only when the supported
platform deviates from the horizontal. If the angle of deviation
is small, as it must be in a case of practical value, the second effect
is also negligible. There remains to be considered only the first
point, the effect of moving the support horizontally. It is suffi-
cient to consider a single plane only, as motions at right angles
produce independent effects. The to and fro motion of the sup-
port, due to rolling or pitching of the ship in a sea, is not strictly
harmonic. It is usually a rough beat motion which can be con-
sidered the sum of two sinusoidal motions of somewhat different
frequencies. Each of these may be considered separately if de-
sired. To a first approximation, however, it is sufficient to con-
sider a simple harmonic horizontal motion of the support. Ob-
viously the motion of the gimbals does not react appreciably to
affect the motion of the ship, hence we may consider the motion
of the support to be an undisturbed sinusoidal oscillation.

PBHDULnX.

The above problem is hence the problem of considering the
potion of a physical pendulum of which the support is given a
sinusoidal horizontal motion.
^_I n Fig. I, we have su ch a pendulum located by the coordinates

* Communicated by the Author.

199

Digitized by

Google

200

V. Bush.

IJ.F.I.

X and *, where x is caused to vary in accordance with the
expression

X =i4 sin w/

The pendulum has constants

m B total mass

h « length from centre of mass to support
a » radius of gyration

Pig. I.

It will also be convenient to use the coordinate y, which for the
small values of ^ to be considered throughout is given by

y - x-bQ
AHALOGOUS ELECTRICAL CIRCUIT.

The formulas for forced harmonic motions of electrical cir-
cuits are in much more convenient form than the formulas for
mechanical systems. It will accordingly be convenient to solve
first the electrical circuit which is analogous to the mechanical
system of our problem, and then to interpret the results on the
problem itself.

jf\

Digitized by

Google

Aug, 1919.I

GiMBAL Stabilization.

201

We will consider first the simple pendulum in which

Such a pendulum when the support is moved in accordance

with

X ^ A sin «/

is analogous to the series electrical circuit of Fig. 3, containing
resistance R, inductance L and capacity C, when independently

Fig 2.

of the circuit a charge is supplied to the condenser in accordance
with

g = sin «/
This will be true when we have in a pair of leads connected across
the condenser, the current

dq ^

» = -^ « Qw cos w/

Using the vector notation this would be written

Digitized by

Google

202

V. Bush.

[J.F.L

If /i is the vector current in the inductance, we may write the
relation between /^ and / by considering that / divides into parts
proportional to the admittances of the two branches. That is

^»-^ — Tmn:

' iO"

i-L Ci»* +7 R C« i-L Co* +j RCo

TRAHSFBR TO XBCHAHICAL STSTBX.

Considerable care must be used, in interpreting this result on
the mechanical system, to obtain exact analogues.

We have already set the maximum quantity Q analogous to

Pig. 3.

the maximum displacement A. Hence the current in the leads is

analogous to -— or jr. If a displacement A is produced, and the

centre of mass is simultaneously prevented from leaving the
centre line, there will be, for a small angle 0, a back force produced

equal to -^ /i, as can be seen from Fig. 4. Analogously in the

electrical circuit if a charge Q is introduced through the mains,
and the branch circuit is open so that this affects the condenser

only, there will be a back electromotive force -^. We thus have

C analogous to —

Digitized by

Google

Aug., iQig.]

GiMBAL Stabilization.

203

The kinetic energy of the mechanical system in the case of a
pendultim with concentrated bob is

and the energy stored in the magnetic field of the electrical sys-
tem is

Hence L and m are analogous ; and f 1 corresponds to {x - hO) or y,
that is to the net horizontal speed of the centre of the bob.

Pig. 4.

The frictional constant F, which is the force which occurs
when the bob moves at unit net constant speed, corresponds to the
resistance constant R which is the force arising when unit steady
current flows in the branch circuit.

We may make the analogy more apparent by writing the
differential equations for the two systems.

For the mechanical system, equating the forces on the bob,
we have

my-\'Fy™mgQ

which may be arranged

fny •\. Fy + -J y ^ -^ A anut

Digitized by

Google

204 V. Bush. U-FI-

For the electrical system, summing the voltages about the
circuit

which becomes upon differentiating and substituting

jL ti + i? ti + ^ »i = ^ Q<a cos <at

Place side of this the derivative of the equation for the mechani-
cal system

my -{- Fy + -^ y ^ -1 ^w cos "/

and we may read off immediately the analogies

m
F
b_

u
L
R

Inserting these quantities in the expression above for the electri-
cal circuit, we obtain for the mechanical system

bo* , . Fbu>

bi^ . , Fbu

and since y - x-bO, and x = A sinm t.

K"'-t'-'^)

We are interested in the maximum value to which 9 attains, and
hence in the maximum value of the above vector expression,
which becomes when simplified

This formula checks dimensionally, thus affording an indi-
cation that the substitutions have been made correctly.

Digitized by

Google

Aug., iQig.] GiMBAL Stabiuzation. 205

When the frictional force is zero it reduces to

$max — . g

These formulas hold only for small values of ^, and the absolute
value of the result should be considered irrespective of sign.

When there is resonance, that is when the period of oscillation
is the same as the natural period of the pendulum, which will
occur when

"-Vi

we have

and the formula shows that a large angle may result from even a
small amplitude of oscillition of the support. On the other hand,
when b is very long, the angle of deviation is nearly zero.

In the above the frictional force is assumed proportional to
y, that is to the net velocity of the bob through the medium ; and
the friction of the pivot is considered negligible, as must be the
case if tipping of the support is not to affect the pendulum. In
many practical cases it is nearer the truth to consider the frictional
force to be proportional simply to bO, that is to consider that the
medium moves with the support.

If this assumption is made, the differential equation for the
mechanical system becomes

my + Fv-h-T^y™ -A A*-* cos w/ - F Au* sin <•>/

In Fig. 3, if we alter the current leads to be connected across
the coil alone, instead of the coil and resistance, the equation for
Ihe circuit becomes

L ii 4- Rii + -p; ti = 7; 0" cos w/ - RQt^ sin w/

The same analogy thus holds as before, and if this new circuit
be solved, and the substitutions made, we obtain for the maximum
deviation for the assumption that the medium moves with the
pivot :

ffmax =

V('-i)"M^)'

which reduces, upon setting F = 0, to the same simple formula
for the frictionless case.

Digitized by

Google

206 V. Bush. [JF-l-

PHYSICAL PBHDULUX.

We will now consider the case where all of the mass cannot
be considered as concentrated at a point, as is the case for the
systems shown in Figs, i and 2.

The peculiarity of this case is that there may be kinetic energy
stored in the system even when the centre of mass is not moving.
li X and are both increasing in such a manner that

y = i-bB

is zero, there still is a kinetic energy of rotation about the centre of
mass. If "a" is the radius of gyration about the pivot, the radius
of gyration about the centre mass at a distance "ft" from the pivot
will be

and the above kinetic energy will hence be equal to

^ (a>-y) ^

tn '

Consider now the circuit of Fig. 5, in which there is added
the inductance " 1 " in series with the condenser. The circuit
may store energy in a magnetic field even when there is no cur-
rent in the branch circuit, that is when

•i - a .

An analogy with the mechanical system may be set up for this
circuit exactly as before, and by the same reasoning as above used
we have

Electrical Mechanical

»l
ft

k-btf

b/mg

Now when »i = 0, the energy in the magnetic field is

i^'

and we see that if this is to correspond to the kinetic energy above
when fa is set equal to bO we must have

Electrical Mechanical

If now bO is taken as zero so that we have simply translation, the

Digitized by

Google

S..19I9.]

GiMBAL Stabilization.

207

^^^tic energy is — ' Also, if », is zero so that i = n, the magnetic
Clergy is ^^ and since t and x are analogous, we have

Electrical Mechanical

as before.

Fig. 5.

^^ may check the consistency of our analogy as follows : In
^t cVectrical system assume i = 0, and hence ii = »2. The mag-

Similarly in the mechanical system, assume the pivot at rest, and
the pendulum simply rotating. The kinetic energy is then

Hence we must have the analogy l + /

But we already have /

so that we must have L

but this reduces to simply L

mo*

Digitized by VrrOOQlC

208 V. Bush. [JF.i.

as before, giving us a check on the analogy as far as this part of
the circuit is concerned.

Now in the electrical system we have

/. -/-

'"*-Thr "*''•

^^"^ I - (/ + L) a»« + jRCi^
Hence by analogy in the mechanical system we have

bg ng

and from this by the same process of reduction as used before, we
may obtain for the case of the medium at rest :

ffmax

a \[ '-^)-('-^K'-^r"')+(^)l+(77)('-Tr"')

\bg I '^ \mgj

it will be noted that this formula reduces to the one derived for a
simple pendulum when a = b, and also that it is dimensionally
correct.

When F = it reduces to

Smax «^; g

a'
This formula is particularly interesting in showing that when j

is large, that is with a pendulum of large radius of gyration,
mounted only slightly away from its centre of mass, the angle of
deflection will be very small. Also resonance may be obtained
exactly as before, the frequency of oscillation in this case being

2x y o«

GYROSCOPIC STABILIZATION.

The effect of a very long pendulum may be obtained in an
instrument of small dimensions by the use of the gyroscope.
An arrangement of this sort is shown in Fig. 6. The size and

Digitized by

Google

Aug., 1919J

GiMBAL Stabilization.

209

speed of gyro, and the strength of the restoring spring, determine
the constants of the equivalent pendulum.

Assume first that the weight of the frame can be neglected in
comparison with the gyro.

Let the gyro be of such size and speed that a unit torque
about the pivot causes precession at the rate of p radians per sec-
ond. Let the spring be of such strength that a displacement of
the gyro of one radian brings to bear on the gyro a restoring
torque s. Let the centre of gravity of the system be a distance c
below the pivot, and let the mass of the system be M .

Fig. 6.

Consider the system initially displaced through a small
angle <^, the gyro being in mid position. A torque Mgc4» acts on
the gyro, and it precesses at a rate

Mgcp^ radians per second.
The spring then exerts a restoring torque

sjMgcp^ di
and under its influence the gyro precesses about the pivot at a rate

Mgscp^j^ di radians per second.

That is

J^ = - Mgscp^f^t

S " - ^^''^'^

The pendulum will then oscillate in accordance with the formula

9 « ^0 sin Py^Mgsct

Digitized by

Google

2IO

V. Bush.

[J. F. I.

If b is the length of the centre of gravity of the equivalent physi-
cal pendulum, and a is its radius of gyration we have

from which

V^^l

g(Mscp')

Mscfl'

Disregarding friction we may then write for the maximum devia-
tion of the pendulum from the vertical when the support is moved
harmonically a distance A either side of the centre position

9max =■ o^
h

Bmax

_J 1

Mscp^ «»

The rate of precession of a gyroscope is given by

*-- ^r

where

and
Letting

^ is the angular velocity of precession,

/ is the polar moment of inertia of the wheel,

V is the angular velocity of the wheel,

T is the applied torque.

T - I

we have
from which

and thus

P-Ti

I
IV

Msc

f^max

pyt
Msc

In order to find a, assume the pendulum to be hanging vertically,

with the gyro in its mid position. Suppose now we apply a torque

T to deflect the pendulum from its central position. The gyro first

precesses at a rate

T
'^ ^ fy radians per second,

Digitized by

Google

Aug., 1919.I

GiMBAL Stabilization.

211

whereupon the restoring spring exerts a restoring torque equal to

sTt

which in turn results in a precession in the direction of the applied
torque at a rate

=5^ radians per second.

Plate I.

z
<

.4.
.3
.2
.1

a E

04 -

FLLi
SIM

;tio(

'LE

1 vs

PEN

17.1

55^

n.4

"-y

5.7

01 —

2.3

1.7

1.1

a 4- 6 a 10 12 14. 16 "b"case i
10 15 20 25 30 as 40 4s''b"ca3«n

FEET

The angular a.cceleration is thus

If we consider a physical pendulum of mass M and radius of
^ration a acted upon by torque T, the angular acceleration will be

Hence we have

Digitized by

Google

212 V. Bush. tJFl-

and since from the above

b ~~ sMc

it follows that

h = c

Thus the effect of the gyroscope is simply to cause the equiva-
lent radius of gyration of the system to be increased to the value

ViSr
Usually with gyroscopic stabilizing-^ will be so small that

only the gyroscopic effect need be considered, and unless «> is very
small we may write approximately

emax = AMscpl^ •= -j^
EXAMPLES.

In the following illustrative examples we will consider two
cases.

Case No. i is intended to be typical of what will be found on
smaller boats. The roll is considered regular and 30® each side
of the vertical, occurring with a period of five seconds. The
instrtunent is assumed mounted at a distance of 4 feet above the
axis about which the craft rolls. We then have in terms of feet
and seconds

A — 2 ta ^= 2 tr .2

and

X — 2 sin 1.256/

Case No. 2 is intended to represent a large ship. The roll is
considered to be 15° either side, with a period of 15 seconds, the
instrument mounted 20 feet above the centre of roll.

Then

i4 = 5.2 , w — —

and

X - 5.2 sin .418/
SIMPLE PENDULUM.

Consider first a simple pendulum, and neglect friction. The
maximum angle of deviation is given by

ffmax --

»-i.

Digitized by

Google

Aug., 1919.]

GiMBAL Stabilization.

213

The results of computation for various values of b are plotted
on Plate I for the two cases above.

The curves show that in Case No. i a pendulum of reasonably
short length will deflect about 5 degrees while a pendulum 15 feet
long will deviate an amount greater than twenty degrees, so much
in fact that the formulas no longer hold even approximately.

In Case No. 2 the deflection for a short pendulum will be about
1.5 degrees, this deflection becoming large as the length of pendu-
lum approaches 183 feet.

Plate II.

— 1

1 v:

i.Ri

.D.

iYF

TIC

"5 5-

-Y

g E.S

97 A A

1 T 1 >

•*

*«,

"*"

—

<5 7 1 .

0./ .1 "f"

—

tzi

—

m—

Z A 6 A W 1.2 1.4 1j6 \5 2.0 22 2.4 2j6 2A 3J0 3.2 3.4 3.6

INCHES 'b'Casel.

.1 .2 .3 .4 .5 .6 .7 .6 .9 1.0 I.l 1.2 1.3 14 1.5 1.6 1.7 Ifl

"b"CftS«lI.

This example shows conclusively that a simple pendulum of
reasonable length swung in frictionless gimbals on board ship
cannot be expected to remain vertical within several degrees.

PHYSICAL PEVDULUK.

As a second example consider a fly wheel with heavy rim
swung slightly off centre. Suppose the radius of gyration, which
will be approximately the mean radius of the rim, to be i foot,
and disregard friction.

The formula now is

ffmax =■■

b '

Vol. i88. No. i 124—16

Digitized by

Google

214 V. Bush. [JFI-

On curve sheet 2, are plotted the results with this fly wheel
suspended various distances off centre.

Considering Case No. i we see that when the distance off
centre is several inches, the deviation is several degrees, as with

Plate III.

.0080

.0070

.0060

U .0050

.004-0

.0030

.0020

.0010

1000 eooo 3000 4.000 5000 "V r. p.m.

the simple pendulum. If the eccentricity is shortened the angle
becomes larger, and at one inch is about 15 degrees. If "&" is
made very small, however, conditions improve, and when b is
.12 inches the deflection is 1.4 degrees. If b is made .01 inches

Digitized by

Google

Aug., 1919-1 GiMBAL STABILIZATION. 21$

the deflection will be in the neighborhood of .i degree. In this
latter case, however, there would not be probably enough eccen-
tricity to properly overcome friction. For Case No. 2 conditions
are even less favorable. It will thus be seen that even using a
massive pendulum it would be difficult to design in such a manner
that very small deflections would result.

USB OF GTROSCOPB

Let us now consider the use of the gyroscope for stabilizing.
Suppose the gyro wheel to weigh i pound, with a radius of gyra-
tion of .25 feet, revolving at speeds up to 5000 r. p, m. Suppose
the mass of the whole system to be two pounds, with a centre of
gravity .5 feet below the support. Suppose the restoring spring
to be of such strength that when the gyro is deflected through i
radian or 57 degrees it exerts a force of .05 pounds at a lever arm
of .1 foot.

Then

c = .5
Af= 2
s =.005

The formula is

Omax =

and for the values of the example :
Case No. i

Bmax =

Case No. 2

On Plate III are plotted curves for this example for speeds up
to 5000 r. p, m,, that is up to

y __ ^^5000 _ ^^^ radians per second.
60

It will be noted that at this highest speed the maximum deflection
in the two cases is .0005 and .0014 degrees, respectively. Thus
practically complete stabilization is obtained. •

Meoford Hillside, Mass.,
Nov. 8, 1918.

Msc

«
««

iple:

.78 v»-

20.4

5.2

Digitized by

Google

2 16 Current Topics. [J- F- ^•

Hydro-Electric Development in Ontario. {The Canadian
Engineer, vol. xxxvi, p. 529, June 12, 1919.) — Sixty thousand
horsepower will be developed on the Nipigon River, about sixty
miles northeast of Port Arthur, by the Hydro-Electric Commis-
sion of Ontario, and it is expected that by June of next year two
12,000 h.p. units will be in operation. Propositions from several
leading water turbine builders are now being considered, and
after the contract for the " wheels " is let, which may be Avithin
the next two or three weeks, definite plans will be completed and
active work will be commenced at the site of the new poiver
house.

The Nipigon River flows from Lake Nipigon to Lake Supe-
rior, a distance of about 32 miles. The normal elevation of Lake
Nipigon is 852 ft., and of Lake Superior, 602 ft. There are at least
four power sites on the river, all of which will ultimately be devel-
oped by the Commission. Between Lake Nipigon and Kmma
Lake are Virgin Falls, Rabbit Rapids and Devil Rapids, where
the total head for development through Hannah Lake would be
42 ft. South of Emma Lake are Flat Rock Rapids, White Chute
and Pine Portage Rapids, with a head of 55 ft. South of Lakes
Maria and Jessie — near Cameron's Pool — are two sites. The
upper site affords 65 ft. net head and the lower, 53 ft. The
upper site at Cameron's Pool is considered to be the most advan-
tageous one on the river, and naturally will be developed first.

The design of the proposed plant includes a regulating dam
that can raise the river level to the elevation of Lakes Maria and
Jessie, which will form natural storage reservoirs. It is esti-
mated that a peak load of 60,000 h.p. can be taken care of by the
normal flow, and that is the size of the plant that will be built.

The initial installation will be two units, each 12,000 h.p., but
three more will be installed at a later date. Single runner vertical
water turbines will be direct-connected to 3-phase, 60-cycle, 12,000-
volt, internal revolving field generators, each 10,600 k.v.a. (80 per
cent, factor, maximum rating). The generators will be arrang^ed
for parallel operation and will supply light, heat and industrial
power on the Commission's " Nipigon System." This develop-
ment is further west than any other yet undertaken by the
Commission.

Digitized by

Google

THE PHOTOMETRIC SCALE.*

HERBERT E IVES, PIlD.

Member of the Institute.
niTRODUCTORT.

The term " Photometric Scale " is here used to include, in
reference to photometry, the same kind of collection of constants,
fixed points, methods, etc., as, in reference to thermometry, go
to establish and maintain the thermometric or temperature scale.
Such a scale, rationally based, and adequately specified, is neces-
sary in any branch of exact science, to insure agreement of results
among different workers, and to give their results scientific and
practical value when obtained.

A complete photometric scale has been established and pub-
lished by the present writer during the past few years. It involves
the following factors:

1. Conditions of observation.

2. Method of choosing observers.

3. Relative luminous values of radiant energy of various

wave-lengths.

4. The value of the lumen in terms of the watt of luminous

flux.

5. Standards of luminous intensity.

6. Standards of color difference.

These factors have been interchecked until complete agree-
ment and consistency have been obtained — ^an essential procedure
if photometric methods are to be used in accurate scientific work.
As the scale now stands it provides complete and practical means
for the precision measurement of the luminous values of all kinds
of light sources.

Since its first publication a number of years have elapsed, in
which time additional data have been collected, both by the
writer and by others (notably at the Bureau of Standards),
which now make it possible to fix the constants of the scale with
somewhat greater exactness. It is the purpose of the present
article to gather together in one place all the recommendations
and data which constitute this scale, bringing them completely
up to date.^

* Communicated by the Author.

217

Digitized by

Google

2i8 Herbert E. Ives. [J. F.I.

X. COVDITXOVS OF OBSERVATION.

Since the rdiitive luminosity of the various colors is a con-
tinuously varying function of brightness and field size, it becomes
necessary to choose certain conditions as standard conditions of
measurement. The brightness and field size selected should be
representative of useful working conditions. The measuring
method should be a practical one, of as high precision as possible.

As a result of comprehensive studies the writer * has been
led to recommend the use of a field brightness of 2.5 milli-lam-
berts, and a field size of two degrees diameter. This brightness
is about as high as can be easily handled with the photometric
standards in ordinary laboratory use. It is, however, at the lower
limit of modern working illuminations, and considerably below
normal daylight illuminations. This latter objection is offset by
the use of the small field, which has the effect of shifting the
equivalent illumination upward, so that the final condition does
correspond to modem working illuminations.

A very great advantage of the choice of these conditions is
that imder them the extremely practical and precise flicker pho-
tometer yields (at infinitely less trouble) the same results as are
derived from the less precise method of juxtaposed fields or
direct comparison.'

The complete specifications for the conditions of observation
for precision photometry on the scale under discussion are then :

A photometric field of two degrees diameter, a field bright-
ness of 2.5 milli'lamberts, (A)

The use of the flicker photometer is recommended,*

n. KBTHOD OF CHOOSIVO OBSBRVBRS.

No agreement between different laboratories, nor Useful
photometric results corresponding to an average eye, can be ob-
tained without some standardized method of picking observers
whose color vision is normal or averages normal. The ideal
method of choosing observers would be to obtain the luminous
efficiency curve of the spectrum for each member of the labora-
tory staff, and pick the men to be used by comparison with an
established average luminous efficiency curve. The labor in-
volved in such a procedure makes it, however, impracticable for
general use.

As an alternative simpler method, the author has proposed *
the measurement by each prospective observer of an arbitrary

Digitized by

Google

Aug., igig.] The Photometric Scale. 219

color difference whose value for the average eye has been estab-
lished by numerous observations. Only those observers should
be used who are normal, or who form a group which averages
normal.

The color difference proposed was that furnished by placing
over a "4-watt" carbon lamp two inorganic salt solutions in
layers one centimetre thick, whose composition was such that the
absorptions were equal for the average eye. The group to be used
in any color difference measurement was then such a group that
their average reading of the two solution transmissions was
equality.

The original solutions were worked out on the basis of
measurements made on 61 observers. At a later date, Crittenden
and Richtmyer at the Bureau of Standards • made measurements
upon about double this number of observers, and as a result
found a slight change necessary in the ratio of transmissions.
This in turn indicated a change of composition in order to give
two solutions of equal transmission. Making this change in
composition, the method of choosing observers may now be
specified as follows :

Observers for making color difference comparisons shall be
selecetd by measurements on two test colors. The constitution of
the YELLOW test color is

*J2 grams potassium bichromate to one litre of water. The
constitution of the BLUE test color is

57 grams copper sulphate to one litre of water.

The group of observers, preferably not less than five in num-
ber, should obtain an average value of unity for the ratio of the
transmissions of these test color solutions when used over a " 4-
watt " carbon lamp. (B)

Details as to the technic of preparing the solutions, the choice
of tanks, and the temperature coefficients, may be obtained from
the original publications.^* *

ni. RELATIVE LUKIROUS VALUE OF RADIANT ERBROY OF VARIOUS
WAVELENGTHS.

An essential part of the photometric scale is the relation be-
tween radiant energy and luminous energy, for all colors, or the
luminous efficiency curve of the spectrum. Only by an exact
knowledge of this can light and energy be coordinated, and pho-
tometry become a really precise branch of science. It should be

Digitized by

Google

220

Herbert E. Ives.

[J.F.L

self-evident that the luminous efficiency curve must be obtained
by the same photometric method as is used in the photometry of
the integrated luminous fluxes.

In the scale as published by the writer the luminous efficiency
curve was arrived at by empirical variation of a curve obtained
by direct measurement with a limited number of observers. The

Table I.
Luminous Efficiency of the Spectrum.

Physical
Photometer

Nutting

Calculated

(3-Tenn
Expression)

.400m

.0021

.0024

.410

.0036

.0032

.420

.0065

.0096

.430

.0115

.018

.440

.022

.029

.450

.038

.041

.460

(^007)

.061

.058

.47c

(.029)

.101

.090

.480

(091)

.149 .

.138

.490

(.185)

.215

.500

.317

.314

•341

.510

.478

.456

•493

.520

.652

.616

.638

.530

.799

.815

•795

.540

.911

.925

.919

.550

.985

.986

.992

.560

.999

.995

•999

.570

.957

.949

.953

.580

.888

.871

.879

.590

.782

.762

.777

.600

.639

.634

.633

.610

.494

.498

.491

.620

.365

.368

.362

.630

.261

.268

.240

.640

.170

.166

.164

.650

.094

.105

.101

.660

.051

.058

.060

.670

.029

.032

.038

.680

.014

.016

.022

.690

.008

.oc8i

.013

.700

.0036

.007

variations were made in the constitution of a " luminosity curve
solution " used with a non-selective radiometer to form a precision
physical photometer, and the modified curve was checked by
measurements on the " test colors " and on a large range of black
body colors, until it gave results completely agreeing with the
visual method.

Digitized by

Google

Aug., I9ig^]

The Photometric Scale.

221

With the slight change of composition made necessary in the
test color solutions by the measurements on a larger number of
observers, a corresponding change was called for in the lumihoUs
efficiency curve. This was made by an empirical change in the
composition of the physical photometer solution, and published
some time since,* without, however, any figures on the spectral
character of the change resulting.

Fig. I.

40 ,-- ;

1 7 1

1
f> 1

.O 1 4 -

A — • i

••

1 ;

2 . i

i '
] \ J

,,,^

<0 .45 50 SS .60 65 70^

Luminous efficiency of the spectrum.

Dotted line — Physical photometer solution.
Dashed line — Nutting^ curve as revised.
Pull line — Calculated from 3-term expression.

There has recently been made, through the courtesy of the
Bureau of Standards, a precision measureirient of the spectral
transmission of this revised luminous efficiency curve solution.
This measurement was made by both visual and photo-electric
spectroradiometry, and is probably considerably more accurate,
especially at the blue end of the spectrum, than the measure-
ments made and publi^ed on the earlier solutions. The results
of this measurement are listed in Table I, and are plotted (dotted
line) in Fig. i.

Digitized by

Google

222 Herbert E. Ives. [J.F.I.

In comparing this with the earlier curve (which Hes further
toward the red) and with other pubUshed curves, the interesting
fact was discovered that it almost exactly agrees with the one
obtained by Doctor Nutting some years ago, using substantially
the photometric method here outlined, although with a random
group of 21 observers. Nutting's curve as originally published
did not prove suitable as tested on the physical photometer," but
it has since been revised as the result of later data on the energy
distribution of the light source used, and it is this revision which
(kindly furnished by Doctor Nutting), as shown by the dashed
curve in Fig. i, is practically coincident with the lately obtained
luminous efficiency curve solution transmission. The difference
in the blue is to be decided in favor of Nutting's curve, since the
physical photometer tests would be inadequate to detect a defi-
ciency of this sort.

The significance of this agreement is that each curve supple-
ments the other. Nutting's curve was obtained with a group of
observers whose characteristics are not known in terms of the
test colors, so that while its shape and end characteristics are well
established, its position in the spectrum may be shifted from the
average of a larger group. On the other hand, the physical
photometer solution is accurately coordinated with the test colors,
but its shape and characteristics at the ends of the spectrum
(particularly the blue) might be only approximately right.^*

It has been shown by Kingsbury " that the luminous efficiency
curve of the spectrum may be well represented by a series of
terms of the form

j.(i?i)"..('-^)

Both of the curves under discussion are well represented by a
three-term expression of this form with constants given below.
As a consequence the formulation of the relation between the
luminous values and the energy values of the spectrum may be
expressed as follows:

The luminot4s efficiency curve of the spectrum is given by the
expression (C)

Digitized by

Google

Aug., 1919] The Photometric Scale. 223

The luminous efficiency curve of the spectrum is accurately
copied for purposes of physical photometry by a solution of
composition (D)

Cu a, 61-25 grams

Co (NH4), (SO4), MS grams

K, Cr O4 1 .9 * grams

Water to i Hter

The original paper " should be consulted for details of the
technic of the physical photometer.

IV. THE VALUE OF THE LUXEH IH TERMS OF THE WATT OF LUXIHOUS FLUX.

The common unit of luminous flux, the lumen, is entirely arbi-
trary." It is related to the watt of luminous flux by a constant,
commonly called " the mechanical equivalent of light." The
simplest method of obtaining the value of this constant is to
measure in absolute units the energy transmitted by a luminous
efficiency curve screen from a light source of known lumen out^
put. This measurement has been carried through with the origi-
nal luminous efficiency curve solution, giving a value for the
lumen of .00160 watts. In order to correct this to the newer
curve it has only been necessary to obtain the luminosity curve of
a standard (" 4- watt ") lamp for both curves, which is easily
done graphically, and measure the relative areas. Carrying
through this procedure gives as the new figure .00156. The next
element of the photometric scale is therefore specified as follows :

The lumen is equivalent to .00156 watts of luminous flux. (E)

V. STAHDARDS OF LUXIHOUS IHTEHSITT.

The question of a primary standard of light assumes some-
what less importance than has been accorded to it in the past,
immediately luminous flux is properly analyzed into its physical
part and its physiological part. The rational unit of luminous
flux, the watt, is to be maintained by the same standards as those
employed for the measurement of any form of radiant energy.
Any light source is giving unit illumination when its radiation
measured on the far side of a luminous efficiency curve screen is
of unit value.

As a matter of convenience, however, it is desirable to have
certain fixed points or standards, by which the value of the unit
may be obtained at any time without going through all the steps

Digitized by

Google -^

224 Herbert E. Ives. [J. F.i.

requisite for its original establishment. In the case of light the
fixed point presenting the greatest merit is the black body at the
melting point of platinum. Its exact value is still subject to re-
finement of determination, but as a result of the most recent
measurement " the following specification may be given :

As a standard fixed point in photometry the brightness of the
black body at the melting point of platinum may be adopted as
S?-35 candles per square centimetre, f F)

YI. STANDARDS OF COLOR DIFFERENCE.

In the interest of economy of labor, it is desirable to embody
the results of measurements carried out under the most elaborate
standard conditions, in subsidiary standards. In the case of
color difference photometry the subsidiary standards take the
form of illuminants of different color, or colored media, whose
characteristics are reproducible and have been made the subject
of measurement and specification.

In order to have such standards to meet all contingencies it
would obviously be njecessary to have sub-standards of an enor-
mous number of colors, and in the course of time it is, in fact,
likely that the number of color difference standards prepared for
use with different illuminants will become quite large. Up to
the present, however, the only standards of this sort that have
been developed are for the most commonly occurring type of
color diflFerence in ordinary illuminants, namely, the black body
series.

The set of such standards belonging to the photometric scale
under discussion consists of a yellow and a blue solution, made
up in conformity with the suggestion of Professor Fabry, of such
spectral character of absorption that increasing diflFerences of
color along the black body scale are met by increased concentra-
tions." The composition of these solutions is given below. The
transmissions were measured, at the time of the publication of the
composition, in terms of the group of observers available at that
time, and it is to be expected that the somewhat altered scale due
to the greater number of observers now embodied would alter
the values. As a matter of fact, however, measurements made
by Crittenden and Richtmyer* on one of these solutions show
the original calibration to hold even with the larger group of
observers. This is to be ascribed to the fact that the color differ-

Digitized by

Google

Aug., 1919.] The Photometric Scale. 225

ences involved are much less than those of the " test colors," in
whose value occurred a difference of only two per cent. Until,
therefore, more refined measurements dictate a revision of the
Fabry solution values, these stand as in the original publications.
They are embodied in the following :

A yellow absorbing solution for use with color differences of
the black body type is composed of

Cobalt ammonium sulphate 100 grams

Potassium dichromate 733 grams

Nitric acid (1.05 gr.) 10 c.c.

Water to i liter

Its transmission in a thickness of one centimetre as compared
with clear water is given by the formulce,

logi* T = -0.245 C •••—-when used over a " 4 watt " lamp.
Jogj» T =-1-0.366 C *••• — when used over a test lamp to bring the
light to " 4 watt " color,
where c is concentration ; (G)

A blue-absorbing solution for use with color differences of
the black body type is composed of

Nickel ammonium sulphate 50 grams

Ammonium sulphate 10 grams

Ammonia 0.90 gr. 55 cc

Water to i liter of solution.

Dilute with water containing 10 gr. ammonium sulphate per liter.

Its transmission in a thickness of one centimetre as compared
with clear water is given by the formula (H)

logj, T = -0.539 C >.•■ — when used over a "4 watt" lamp.

Details as to technic, temperature coefficients, etc.,. are to
be found in the original publications."* "

YII. DISCUSSION.

The system of photometry which is here summarized will
appear to many to be a complicated and difficult one. It is to be
remembered, however,, that comple^city/is inherent in any com-
plete scheme for color difference photometry, both because of
the nature of color vision in the individual, and because of the
statistical element which enters due to the varying characteristics
between individuals. Considered from this standpoint it is be-
lieved the system is in reality as simple as an adequate one can be

Digitized by

Google —

226 Herbert E. Ives. [J. F.I.

made. It may be emphasized that it is the only complete system
thus far presented. It is further to be remembered tliat it is not
the intention that the complete photometric procedure be gone
through with every measurement, or in every laboratory. The
ideal is to use the method for the establishment of secondary
standards, by means of which all practical photometry is carried
out with no color differences, leaving the fundamental color dif-
ference measurements to be made in the standardizing laboratories.

NOTES.

^ This paper may be considered as a revision to date of portions of the
communication "Proposals Relative to Definitions, Standards and Photo-
metric Methods," presented to the Illuminating Engineering Society, May, 1915.

■ Philosophical Magazine, July, September, November, December, 1912, pp.
149, 352, 744, 84s, 853.

' The identity of the results given by the two methods under the conditions
specified, and on the employment of enough observers to secure a significant
average from the widely scattering values apt to be obtained in the juxtaposed
field comparison, is a fact of experiment against which no conflicting evidence
has been adduced. It has, on the other hand, been confirmed by the work of
Abney and Watson, and by the extensive study of Richtmyer and Crittenden at
the Bureau of Standards. It is not claimed by the writer, and never has
been, that the two methods give the same results under other conditions. It
was, in fact, his own researches which first showed in what manner and to
what extent the two methods give different results. It is consequently quite
beside the point for critics to attempt to discredit the photometric scale under
discussion by blanket assertions that "the flicker method" gives results different
from "the equality of brightness method." Such criticism is on a par with at-
attempting to discredit accurate methods of linear measurement by stating
that a* bar of lead and a bar of platinum measured at o^ are of unequal
llengths at any other temperature. The necessity for recourse to standard
comparison conditions, due to the fact that response to varying conditions is
different in different substances, is not peculiar to heterochromatic photometry.
A red light and a blue light cannot, from the nature of vision, be equal under
alt conditions, and the choice of comparison conditions after a thorough con-
sideration of the questions of utility, practicability and convenience, is entirely
on a par with procedure in other departments of measuring science.

* There appears to be prevalent an idea that " ordinary photometry " and
"the conditions of ordinary photometry" stand upon a firm basis, that they
are sacrosanct, immutable, and in fact give exactly the measurements required
for the proper evaluation of all light quantities. As a matter of fact there is
no basis whatever for such a belief. " The conditions of ordinary photometry "
are to a predominant degree accidental. They have not to this day been
made the subject of definite specification, and have never, previous to the
writer's researches, been studied .quantitatively at all with reference to the
phenomena of color perception. The only requirement for " ordinary photom-

Digitized by

Google

Aug., 1919.] The Photometric Scale. 227

ctry" (which is photometry in which no color difference is presenf), is the
use of a sufficient field brightness and size to bring the observations into die
region of respectable precision of setting, when the eye is the null radiometer
employed. The most common conditions (in American practice) are an il-*
lumination of about 10 metre candles (near the lower limit of the region of
good photometric precision), and a field of about 5 degrees diameter. The
former condition is directly traceable to the candlepower and physical di->-
mensions of the light sources and standards in common use a decade or two
ago ; the latter probably is connected with the size of prism which it ^as orig-
inally found practicable to grind to the Lummer-Brodhun form. But neither
condition is authoritatively specified or generally adhered to. As long a^s
there is no color difference present it is unnecessary to hold 'to narrow coti-
ditions. In fact had the thermopile been as sensitive and as practical in form
thirty years ago as now, it is not beyond the bounds of possibility that it
would have been seriously advocated as a photometer, for which 'pln'f>ose it
would have been entirely suitable, as long as no difference of color existed be^
tween the light sources under comparison. The error of using -the 'Coa^
ditions of ordinary photometry " for colored light comparison is of the ^ame
nature, even though not as great, as is the use of a. thermopile. It r^ in-
•evitable that when color differences are to. be compared a narrower. and more
•exact choice of conditions must be made than sufficed formerly. It w:0uld have
been entirely an accident had the " conditions of ordinary photometry"; (such
as they are) been identical with those dictated by a basic, study of theheterpr
chromatic problem. ,-

It must not be overlooked by those who display concern for "ordinary
photometry" that the conditions here specified for color, difference photom-
etry yield identical results to "ordinary photometry" for the only measure-
ments for which the latter was ever suited, so that there is nothing revolu-
tionary involved in picking conditions suited to color difference photometry.
The adoption of definitely specified conditions is a step inseparable from
the advance of any science. The "eye of the skilled workman" has had to
yield to the pyrometer in heat measurement, and in photometry the " practiced
observer " must yield to a well-considered and definitely specified photometric
procedure. .

• Trans. Ilium, Eng, Sac, x, No. 3, 191 5.

• Bull. Bur. Stds. 14, 87, 1918.

' T^ans. Ill, Eng. Soc. viii, p. 795, 1914 ; Trans. III. Eng. Sac, p. 253, 1915.

' The method of . measurement, and the method of choosing observers, as
here specified, are those now in use at the Bureau of Standards.

•Journal Franklin Institute, July, 1918, p. 121.

*• Physical Rev., Nov., 1915. P. 319-

"Two other comparatively recent determinations of the luminous effi-
ciency curve of the spectrum are not included for consideration because they
were not made under the conditions which fix the photometric scale under
discussion. The extensive investigation of Coblentz (Bull. Bur. Standards
303, Sept 12, 1917, p. 168) , although stated to be carried out in accordance with
the procedure of the present writer, was not, in the vital particular of field
brightness, which was not 'over one^uarter that here specified. As a c'onse-

Digitized by

Google

228 Herbert E. Ives. [J. F.I.

quence the curve obtained by him is shifted toward the red. An experimental
test of Coblentz's luminosity curve solution, based on his determination of
the luminous efficiency curve, shows an error on the test colors of 4V2 per
cent (Journal Frankun Institute, July, 1918, p. 121). The determination
by Hyde^ Cady and Forsythe {Astrophysical Jour,, Sept, 1918, p. 65) was made
by the cascade method, which die writer had already shown would give the
same results as the flicker method under the small field high brightness con-
ditions specified by him. The investigators quoted, however, carried through
their work under conditions of brightness and field size (the latter not
specified) supposed to correspond to " the conditions of ordinary photometry/*
which as abeady pointed out, have no rational basis for use in color difference
comparisons. As a consequence of their use of these conditions their curve
is shifted toward the blue, as compared with the one here given. Neither
Coblentz's nor Hyde's curves are coordinated with any accurately speci-
fied observing conditions nor method of choosing observers. They con>
stitute isolated elements of photometric scales which are not only incomplete
bat without sound bases for adoption even if supplied with their missing parts.

^Physical Rev,, Feb., 1916, p. 161.

" See Journal Franklin Institute, Oct, 1915, p. 409.

''Journal Franklin Institute, July, 1918, p. 122.

" Trans. III. Eng. Soc. p. 796, 1914 ; Trans. III. Eng. Soc, p. 253, 1915.

" The only other color difference standards of a reproducible nature thus
far published are furnished by the tungsten lamp characteristic equations of
Middlekauff and Skogland (Bull. Bureau Standards, No. 258, p. 483, Oct., 1914)-
Their validity is conditioned by the uniformity of characteristics from one
lamp to another, which is hard to guarantee in so complicated a product as
the modem incandescent lamp. Moreover, the equations as published are
based on photometric measurements carried out under conditions and with
observers neither of which were the subject of study or selection, or of
specification. It is understood that a revision of these equations is contem-
plated, based on photometric determinations made on the scale here described

APPENDIX.

APPLICATIOH TO THE BLACK BODY.

The luminous efficiency curve of the spectrum may be applied
(due to the possibility of summating luminous radiations) to the
calculation of the luminous characteristics of any radiation of
known physical constitution and intensity. The most important
case is the black body, or complete radiator. Luminous efficiency
curve equations of the form above given may be combined with
the Planck black body energy distribution equation and integrated
lo give the luminous radiation, in ergs or watts of luminous flux.
From this, upon division by the constant relating the number of

Digitized by

Google

Aug., 1919.]

The Photometric Scale.

229

watts of luminous flux to the lumen (mechanical equivalent of
light), the flux, or brightness, may be immediately derived in the
ordinary units of lumen and candlepower.

The form and derivation of these equations has been given
by Kingsbury.^ In re<:alculating them for the new luminosity
data here presented several deviations have been made from the
previous procedure. As given by Kingsbury the constants are all
worked out numerically, on the basis of a chosen value of the
black body constant Cg, (14370). Experience in being forced to
recalculate the data to several other temporarily more popular
values of the constants, or to values which would make possible
a real comparison of work of different observers, has suggested
the desirability of stating the equations in such form that the
place of occurrence of all the black body constants shows clearly.
This, in turn, is but the first step in the search for a mode of
expressing the luminous flux equations in \^hich the calculations
once made and tabulated will be independent of any particular
choice of the black body constants. While the uncertainties in
the values of these constants are becoming gratifyingly small,
they still amount to a great deal when translated into terms of
luminosity ; and the refinements yet to be made in their determi-
nation will be important factors in their use in luminous flux
equations. The desired form of the luminous flux equations,
into which the latest and best values of the constants can be intro-
duced at any time, is furnished by taking advantage of the fact
that the two variables, shape of the emission curve (determined
by — ) and luminous efficiency (ratio of the light-evaluated to
the total energy), are connected by definite values which may be
calculated without assuming definite figures for the black body
constants. Accordingly the data herewith plotted are values of

(where L is the light-evaluated, R the total radiant energy),

against •^.

Expressed in this new form the flux equation as developed by
Kingsbury becomes

^(?yx

.01Q22

h('-¥)'

*i^

, \n\m T J

(I)

Vol, 188, No. 1 124— 17

Digitized by

Google

230

Herbert E. Ives.

[J.F.I.

Upon introducing the constants of the luminous efficiency
curve equation as developed in the body of the paper this equa-
tion becomes

.28730 .0070326

{1304

R \T/ Loo8qq3-^+i) ^ l.ooi282-+i\

. .022S8l \

(2)

Table I.
Black Body Luminous Characteristics.

Ct
T

L
R

.0514

T.71096

.546/"

.1296

T.II261

.5515

.1085

T.0355I

.5575

.05755

7.76102

.5635

.02416

7.38303

.569

.008778

7.94340

.5745

.002864

^•45697

.5795

.0008768

T.9429O

.5845

.0002479

T.39435

.5895

.00007198

7.85721

.5945

.00001994

7.29937

.5995

.000005217

^.71740

.604

Calculated values, using this equation are listed in Table I
and plotted (in terms of the logarithm of ^ ), in Fig. i.

In order to arrive at definite values of luminous flux it is, of
course, necessary to choose and introduce definite values for the
black body constants. Thus to obtain L, the luminous flux in
watts, we use the relation

L=(|)x<'r* (3)

To obtain the normal flux Lo, we use the equation

To transform these results to lumens and candlepower we
divide by m, the watts of luminous flux in the lumen, thus

^^UJXm- (5)

, fL\ frT*
^o-'^=[R)X^m .(6)

Digitized by

Google

Aug., 1919J

The Photometric Scale.

231

Some illustrations of the use of these equations are of inter-
est. Two characteristic ones are furnished by the luminous prop-
erties of the black body at the melting points of gold and platinum
respectively :

Assuming Millikan's values for the black body constants, we
have for gold, with its well-established melting point of 1336° K.,

Fig. I.

1 ^

logl

1 2 3 4 5 6 7 6 9 10 II 12

Luminous efficiency of the black body.

the value ^}|y = 10.7125 for -^. Using this in (2) we obtain
for \ the figure .000000002172. From (4), taking 5.72 x 10"
for (T we obtain for Lo the value .0001659. Dividing this by
.00156, the value chosen in the body of the paper for m, we finally
get for the brightness of the black body at this temperature, —
0.1062 candles per square centimetre.
The latest determination of this quantity is that of Hoist

Digitized by

Google

2^2 Herbert E. Ives. [J- F- ^•

and Visser.2 Their value is 0.1071. Details of their photo-
metric method are not at present available, so that the accuracy
with which it is represented by the luminous efficiency curve here
chosen is problematical. Furthermore, it is to be noted that the
calculated brightness varies with enormous rapidity^ with the
choice of Cg- On the whole, therefore, the agreement of cal-
culated and observed values to within one per cent, is excellent.

In the case of platinum, if we take the same black body con-
stants, together with the latest value for the melting point, namely,
2037° K., the result for the brightness is 55.9 candles per square
centimetre. Experimental determinations by the writer* gave
this quantity as 58.35. This leaves a discrepancy of four per
cent., which, however, is quite as likely to be due to uncertainty
in the melting point of platinum, and in the value of C2, as in the
photometric method and calculations.

It is evident from these calculations, applied in the one case to
a region where photometric observation is reaching its lower
limit of feasibility, in the other to a region where exact tem-
peratures are still in question, that the photometric methods and
equations are in very practical shape for use. In the form they
are here presented they will be available for calculations of the
highest precision immediately the constants of the black body
are fixed.

A second quantity of interest in connection with the luminous
properties of the black body is the equivalent wave-length or the
wave-length at which the rate of energy emission is varying with
change of temperature at the same speed as the rate of luminous
emission changes. (The equivalent wave-length, which applies
to one temperature, is to be distinguished from the Crova wave-
length, which is the wave-length to be used in comparing emis-
sions due to two different temperatures. To a close approxima-
tion the Crova wave-length is the mean of the equivalent wave-
lengths.)

Expressing the equations derived by Kingsbury ^ for the
equivalent wave-length in terms of the more convenient variables
^ and I we get

Digitized by

Google

^,=

^5>i9.] The Photometric Scale. 233

__ \fir \ n J
p

^'- fcr + V

^~7T~^ — : — . R (7)

^/^

r(^)"^'("-f') (r)'x-

oig22 X

J Cj V + s

. ^-U^T + V
Vntroducing the numerical values derived from the luminosity
curve equation, this becomes

L
R

-52708 _J_ 011757

-ooSmr^'Y"' [001282^^1)''''-^

-049244 "I (8)

y.01064 J? 4- / j J

Values calculated from (8) are given in Table I, and are
plotted in Fig. 2.

The plotted values of A« lie on a smooth curve, which is rep-
resented with considerable accuracy by an equation of the form

^ = a + &(^) +c(f)^ (9)

oolv/ng for the constants we find the following numerical equa-
tion to represent the curve well,

'^ = ,$402 4- .00^2 \Y) "■ 'O00074 Iy) (^°)

It has been pointed out by Foote '^ that an equation of this
lorm may be made the basis of an empirical luminous flux equa-
tion of comparatively simple form for numerical calculation. In
OT^er to form such an equation in terms of ^ ^^^ t we note

Digitized by

Google

234

Herbert E. Ives.

[J.F.I.

that if the luminous radiation is considered as monochromatic we
may represent it by the expression

L = ci'\~^e >r

and 1^ by the expression
L
R

Fig. 2.

\ 23456789

Black body equivalent wave-lengths.

From this is immediately derived the relation

dlog —

(?)

(II)

(12)

- T

1
1

Xe ;

7o7 '

li^ -rf*^

10 11 12

(13)

If now we substitute the complete expression for A« from (lo)
we get

^ '+<?)+'(¥)'^(?)

Integrating this we get

(14)

Digitize(j by

Google

Aug., 1919] The Photometric Scale. 235

(15)

log ^ =

/ft b + Vb'-4ar \ I

Solving for numerical values this becomes

I'j.-i37i6\ (,6)

log k^7z.oos log I I + 4log% — 19.6ZOO

* \% + S3.378J ^

This expression gives results of about one per cent, accuracy,
and is considerably quicker than (2) to work with. Its deriva-
tion presupposes the true values known from the direct procedure.

NOTES TO APPENDIX.

• Physical Review, Feb., 1916, p. 161.

' Hoist and Visser, K. Akad, Amsterdam, 1918.

• In the region of the gold point the calculated luminous efficiency changes
almost exactly i per cent for each unit in the fourth place of the assumed
value of Cx. The present uncertainty in the value of Ci is four or five units in
this place (14300 to I4350).

This rapid variation of calculated luminous efficiency with c, suggests that
a highly sensitive method of determining this constant lies in the experimental
determination of ^ for the black body at the well established gold point. L
could be established photometrically by comparison with a light source of the
same color as the black body at this temperature, but of sufficient intensity
to furnish measurable radiation through a luminous efficiency curve filter of
accurately known transmission. Such a source is at hand in the "4 watt " car-
bon lamp in conjunction with a 90 per cent, concentration "Fabry" yellow
solution.

. * Journal Franklin Institute, July, 1918, p. 122.

• Bull, Bureau Standards, 270, Mar., 1916.

Digitized by

Google —

236 . Current Topics. t J- F- 1-

Salving Trench Hosepipe. (Journal of Industrial and Engi-
neering Chemistry, vol. xi, No. 7, p. 690, July i, 1919.) — An inter-
esting side line of war salvage is being carried on at Hayes,
Middlesex, England, where some hundreds of miles of trench
hosepipe are being disintegrated and the various products recov-
ered for sale. This type of hose contains a large amount of iron
wire and canvas impregnated with a small proportion of rubber.
A special machine has been designed for treating the hose, and
the stripped wire is stated to be worth about $60 a ton at present
prices. The rubber is being reclaimed and the canvas ultimately
finds an application as cellulose. The work is being done on a
part of the premises of a detinning works, where considerable
quantities of scrap tin are now being treated by the electrolytic
process with satisfactory results. Metal containing as much as
99.8 per cent, of tin is being obtained from the scrap.

Zirconium Steels. J. Garcon. (Bulletin de la SociSte d'En-
couragement pour V Industrie Nationale, vol. 131, No. i, p. 148,
January-February, 1919.) — Zirconium is not found in nature in the
metallic state. It occurs in Norway, Ceylon and Brazil, and
nearly everywhere in the form of orthosilicate. Zircon or hya-
cinth contains two-thirds oxide of zirconium or zirconia and a
third of the silicate with some impurities. Its density is very
high, reaching 4.7. Another richer mineral is badelyte, of which
quite copious deposits are found in Brazil and also in Ceylon. This
is a natural zirconia whose content of ZrOg varies from 69 to 94
per cent. Several methods are followed to obtain more or less pure
oxide. Zirconia is employed, in view of its high temperature of
fusion, in the manufacture of crucibles and for the linings of
metallurgical furnaces. Zirconium enters also in the composition
of Nemst-lamp filaments, in the leads of the Bleriot-lamp, and as
a component of a special glass which may be substituted for quartz-
glass.

An important application of zirconium is found in the manu-
facture of alloy steels. Tests at the Ford laboratory on armor-
piercing-bullet-shields have shown that nickel-zirconium steel
plates 10 mm. in thickness have a resistance to penetration equiv-
alent to nickel-chrome steel 16 mm. thick and nickel-molybdum steel
13 mm. thick. The zirconium is added in the form of a 30 per cent,
ferro-alloy. This alloy is produced by reducing the mineral in the
electric furnace with aluminum. It is essential that the alloy contain
not more than 5 per cent, of aluminum, otherwise the presence of
the aluminum diminishes the strength of the steel.

Digitized by

Google

DEVELOPMENT OF AN AIRPLANE SHOCK
RECORDER.*

A. P. ZAHM. PluD.

Bureau of Construction and Repair, Navy Department.

To meet the current needs of the airplane designing staff of
the U. S. Navy, an airplane accelerometer was developed for
measuring the sudden loads and shocks encountered in flying, and
landing. An elaborate instrument of precision was not called
for, but rather a device whose records could be obtained easily
and read directly. For the scale drawings and early tests of the
design here described the writer is indebted to his assistant, Mr.
L. Crook, who first calibrated the accelerometer, then used it on
a flying boat to measure landing shocks.

Fig. I pictures the instrument in course of development. It
consists of many vertical styluses, or pointed rods, supported
individually by springs and recording on a single chronograph
drum over which passes a continuous sheet of sensitized paper.
For measuring upward accelerations the rods, which are all of the
same mass, are pressed upward against stops by springs of graded
intensity, while their pointed lower ends, or needles, are held
within a few thousandths of an inch of the chronograph drum.
When acceleration occurs a certain number of styluses begin to
record instantly, as the intensity of the force overcomes in suc-
cession stronger and stronger springs.

When preparing the instrument for any proposed measure-
ment one sets the springs so as to meet any probable accelerations
that will have to be recorded. By means of the sliding sleeves
shown in the photograph the force of the springs can be adjusted
so as to equal any multiple of the weight of a rod. To this end
one applies in succession to each stylus, by contact with a weigh-
ing scales, forces which are multiples or fractions of the whole
fixed weight of the rod plus half the weight of the spring, while
the springs are adjusted so as barely to support the rod against
the stop. A single rod of brass weighs about i ^ ounces, being
•/s2 inch diameter by 5 inches long.

* Communicated by the Author.

237

Digitized by

Google

238 A. F. Zahm. IJ.F.I.

To prevent the needle from scratching or puncturing the
paper it is cushioned against a spiral spring inside the holder, or
vertical rod, within which it can otherwise slide freely. The
needle at its middle is provided with a shoulder abutting against
the upper end of the small holding and adjusting screw. This
screw can, by rotating, raise or lower the setting of the needle,
and is securely fixed in place by the jam nut shown at the bottom
of the rod. The needle is of brass or German silver, and makes
a clear, fine mark on the chemically treated paper when the pres-
sure is three per cent., or more, of the weight of the holder. One

Fig. I.

per cent, of the weight would be sufficient pressure with styluses
fifty per cent, longer and thicker, for a test has shown that .05
ounce pressure of the needle causes a clear trace.

In the position and adjustment shown, the present instrument
records only upward accelerations, but by inversion can, with-
out further adjustment, record downward accelerations, provided
account be taken of the reversed direction of gravity. Thus, if
when upright, the stylus exerts on the stop a pressure nw, in-
verted it exerts (n + 2) w; and hence records accelerations ng,
(n + 2)g,w being its weight. Without inversion the instrument
also records negative accelerations if the styluses be pressed
downward against their stops. Also in its upright position the

Digitized by

Google

Aug., 1919] An Airplane Shock Recorder. 239

instrument records both positive and negative accelerations when
the springs are set so that some styluses are pressed upward and
others downward.

The special stylus shown on the right of the photograph is
provided at its upper and lower ends with thin cantilever springs
which prevent it from rubbing against the guide plates of the con-
taining box, and at the same time hold the rod upward against its
stop in the manner described for the spiral springs. An instru-
ment with such cantilever, or anti-friction, springs could be used
to measure horizontal as well as vertical accelerations.

In the form here shown the instrument is provided with six
feet of paper driven by an alarm clock at the rate of two inches
per second for such accelerations as are found in aeroplane ex-
periments. This rapidity is essential in order to separate and
clearly disclose landing shocks and structure vibrations; for it is
usually the short hammer-blow shocks of a few hundredths of a
second duration which most stress the under parts of an airplane
in alighting on land or water.

In action the instrument appears to be fairly instantaneous
and free from the oscillations found in a spring accelerometer
whose recorder has a considerable displacement. Thus each
needle records without interruption a definite continuous accelera-
tion beyond a certain intensity, but instantly ceases recording
when the acceleration falls below this amount. It can also simul-
taneously record long and short accelerations. For example,
engine tremors superposed upon an air swell cause a needle to
make a dotted trace; the length of the trace representing the
duration of the swell beyond a certain intensity, and the distance
between dots representing the period of the engine tremor. In
fact, a known engine speed serves to standardize that of the
paper, and a known paper speed that of the engine. The aggfre-
gate tracings of all the needles form a shaded diagram whose
contour is a wavy line like that of a spring accelerometer.

An example of typical records taken on a seaplane is presented
in Fig. 2 of this report The farther stylus, which has its re-
straining spring adjusted to record upward accelerations of twice
gravity, has made a few instantaneous traces separated by long
blanks ; the one set for two-tenths of gravity has made long traces
with short blanks. Both records are dotted, showing engine
tremors. Feeble accelerations were expected, otherwise a more

Digitized by

Google

240

A. F. Zahm.

[J.F.I.

suitable setting of the springs would have been made. They

should have been graded to tenths in the region of two gravities.

Fig. 3 gives an acceleration record of an approximately simple

harmonic motion, somewhat damped, made with the instrument

^0'

1.0

Fig. 2.

TIME IN SECONDS

12 3

Landing accelerations on pontoon of Curtis JN — 4E.

screwed to the end of a vertically vibrating spring-board clamped
in a firm vise on a not very firm table, and with its styluses set
only for positive accelerations. Plotted on the same diagram, as
a line of small circles, are the simultaneous maximum accelera-
tions of a needle inserted in the end of the spring-board and play-

Digitized by

Google

Aug., 1919.] An Airplane Shock Recorder. 241

ing on a sheet of smoked paper moving steadily past it. The line
of circles is a " damped " harmonic with a perceptible " over-
tone," and matches the damped acceleration trace taken simul-
taneously, all recorders being equally distant from the face of
the vise. The actual tracing of the spring-board tip is given in
Fig. 4, and the method of computing from this the maximum
accelerations, which are indicated by the circles in Fig. 3, is de-
veloped in the following paragraph.

Fig. 3.

•T't

J oooHAXIMUH)CCELER/niOHSCOMinJTCDn»MPERIOOAriO/WllITUDtOrS^^

r. o "TRACE- OF- STYLUSES OF- SHOC^RECORDER.

ij APPROXIMATE-CONTOUR-OFACCtLERATION-TRACES-

li- ff ? 9

I I 11 |l «

I I I 1 M II 7

• I • I • II 1; .

M \^ n '1 H ^ S

'1 : » • . I . • I i»

1.4 !

5.2'-

::i.i

! I I • « ' • I • ! , •

J I • • I

I I I I I I

! 1 I 1 • 1 ! 1 1' \ i

I I I

I > I I

T ' 1 ' «

I i I II

I II II

I II I I

> ' !
I I I

75 To IS ^ZJQ ^2^5

TIME IN SECONDS

Calibration diagram for shock recorder.

Without rigorous precision the general equation to the ver-
tical motion of the spring-board tracing point may be written

s + CLS* -^ bs -\-cs =

in which s is the displacement, at any time t, from the point of
rest under gravity, and d^, bs, are retardations due to the air
resistance and internal friction of the vibrating system. The
maximum acceleration for any one vibration occurs when s = o,
and may be written from the equation

s -\- cs = 0'

It is

5l = —CSi

Digitized by

Google

242 A. F. Zahm. [J.F.I.

in which Si is the momentary amplitude. Since the damping is
small, Si can also, without material error, be written in the more
familiar form

when n is the frequency. Now, since Si is approximately re-
corded by the acceleration styluses, and 'su n, are found in the
record of the vibration stylus, the one record can be checked with
the other. This method was used in computing from the trace
of the spring-board's motion, the accelerations indicated by circles
in Fig. 3.

The acceleration records are fairly trustworthy as far as they
go, but lack continuity, like the markings on a yardstick. To

Fig 4.

TIME IN 5THS. OF SECONDS.
Trace of tip of vibrating spring board used in calibrating accelerometer.

disclose accurately the maximum acceleration in any shock the
adjustment of the springs must be close-graded. Thus, if a
maximum acceleration of twice gravity be recorded by styluses
graded to tenths of gravity, the greatest possible error is pre-
sumably one-tenth of gravity, or five per cent, of the quantity
recorded, while the probable error is two and one-half per cent.
Still closer estimates can be made by sketching in the contour of
the traces. The free play of the styluses between their stops
must, of course, be kept small.

Closer agreement between the two sets of superposed values
in Fig. 3 would ensue if the clock ran uniformly; if the paper
were uniformly thick, instead of being spliced; if the needle points
were set 0.004 i^ch from the paper, instead of 0.012 inch; and
if the styluses were given less play between their stops. These
adjustments would be made in refining the instrument. But, even
so, the records would not everywhere accurately disclose the
acceleration, unless made with numerous styluses in close-graded

Digitized by

Google

Aug., 1919.] An Airplane Shqck Recorder. 243

adjustment. At one point, such as the third crest in Fig. 3, the
record might be a mere dot, and hence indicate the acceleration
truly ; at another it might be a dash, leaving the true crest to be
extrapolated. Numerous and close-graded styluses can, of course,
be provided without much increase of cost or weight, if found
desirable for special investigations.

For the immediate measurements in view it was thought un-
necessary minutely to calibrate the shock recorder to a close-
grade scale by experiment. Continuous recording instruments
are in the market, such as the RAF photographic accelerometer,
or in development, such as the Sperry mechanically recording
accelerometer, and these may be had in time. The present in-
strument has served a passing need, and may prove useful for
disclosing hammer-blow shocks too sudden to be faithfully re-
corded by accelerometers of another type.

For a comprehensive field laboratory study of the accelera-
tions throughout an airplane it may be well to measure simul-
taneously the shocks in the undercarriage, the body and the
wings. This can be done either by placing individual recorders
in those parts, and synchronizing them, or by placing shock re-
ceivers there and recording on a central chronograph. The
present instrument, or a simpler one consisting of plane bar
springs, could be used as a contact maker in various parts of an
airplane to operate recordinjg magnets at a central drum. Such
an apparatus can easily be arranged, and may be expected to
record with about the promptness of a ballistic or an astronomi-
cal chronograph.

For instantly indicating to the pilot the comparative stress-
ing of his machine a number of simple bar-spring contact makers
of graded strength can be coupled to a row of tiny electric lamps
on the instrument board. These would brighten successively,
and indicate by their various colors, positions, or markings, the
degree of stress put upon his craft. A tentative instrument of
this kind has been tried incidentally to the present study. Such
cantilever styluses, or contact makers, have the simplicity and
compactness of a row of piano keys, but are not preferred to the
endwise-moving styluses because they are more affected by angu-
lar accelerations about their centres of gravity, or points there-
about, than are the rods used in the present instrument. Obvi-
ously the contact points could be used with a smaller gap than
have the needles recording on paper.

Digitized by

Google —

244 A. F. Zahm. [J.F.I.

Without its base the present instrument, whose case measures
9 inches by 6 inches by 1.5 inches, weighs eight poimds, being
riiade almost wholly of brass. By using aluminvmi, where prac-
ticable, the whole weight can be reduced to about two pounds. In
this style the clock would form part of the case, and the whole
could be screwed to the instrument board of an airplane.

Lignum-Vitae, the Vital Wood. S. J. Record. {Scientific
American Supplement, vol. Ixxxviii, No. 2270, p. 4, July 5, 1919.) —
The propeller shaft of every battleship, every destroyer, every
transport, in fact, every large steamship, revolves in a wooden
bearing at the stern end. Of all the thousands of woods in the
world, true lignum- vitae, a native of the West Indies and certain
other parts of tropical America, is the only one that has been
found equal to this exacting service. The peculiar properties
which so well fit lignum-vitae for the purpose are due to the
arrangement of the fibres and the resin-content of the sap cells.
The fibres never run straight up and down the log, but weave
back and forth in a serpentine manner that cross and criss-cross
like the corded fabric of an automobile tire. The result is a
material of extreme tenacity and toughness. When the sap cells
cease to function, their every nook and cranny become filled with
a resin which is about a third heavier than water. The result is
a material which weighs about 80 pounds per cubic foot.

Stern bearings provide the most important use for lignum-
vitae but by no means the only one. Formerly it was in g^eat
demand for bowling balls, but now only one ball in ten is made
of wood. A large quantity of low-grade logs, known as " cut-
ting-up " wood, is consumed in the manufacture of rollers for
furniture casters. Small round sticks make excellent mallets
and fill a large demand, especially in England. Another impor-
tant use is for sheaves of pulleys, and they have been known to
last in constant use for seventy years. Another nautical applica-
tion is for "dead-eyes," a small flattish block with a grooved
rim to fit in the bight of a- rope or encirded by an iron band,
pierced with three holes to receive a lanyard, and used to extend
the shrouds and stays. Among the miscellaneous uses may be
mentioned stencil and chisel blocks, watchmakers* blocks, mor-
tars and pestles, dowels, golf-club heads, wooden cogs, water
wheels and block guides for band saws. In building the Panama
Canal, the true lignum-vitae made the most serviceable railroad
ties that could be obtained. Between 150 and 200 tons of genuine
lignum-vitae are used every year in New York for fuel in grate
fires. The very dense nature of the wood, together with the heavy
resin content, produces a fuel with intense glowing heat and good
lasting qualities. This provides one outlet for defective and
crooked logs which are found in every shipment.

Digitized by

Google

Htch pockets and their relation to the
inspection of airplane parts.*

J. R. WATKINS.

Assistant Engineer in Forest Products, Forest Products Laboratory, U. S. Forest

Service, Madison. Wisconsin.

Member of the Institute.

In the inspection of important wood parts for airplanes it is
essential to know as accurately as possible the effect of any defect
on strength. In the early days of airplane manufacture the builder
could go to almost any length in securing wood entirely free from
knots, imperfections of grain, pitch pockets, or any blemish or
defect ; in other words, absolute perfection could be insisted upon.
When airplanes began to be manufactured on a large scale for
war purposes and we began to look forward to a commercial
development of the airplane it became impossible to insist on this
absolute perfection. Consequently, accurate knowledge of the
effect of all sorts of defects is becoming increasingly essential.

Among the defects found in the coniferous species used for
airplanes, such as spruce and Douglas fir, a common one is pitch
podcets. This article is a brief resume of theories advanced to
account for the presence of pitch pockets and the results of tests
to determine the effect of pitch pockets on the strength of airplane
wing beams. The tests were made at the Forest Products Labora-
tory of the United States Forest Service, in cooperation with
the Air Service of the Army, and the Bureau of Construction and
Repair of the Navy.

ORIOIV AVD OCCURRBVCB OF RBSIV POCKBTS.

Resin pockets are hollow recesses in the wood of conifers,
which are more or less completely filled with resin.

A theory advanced about 75 years ago is that they are
caused by the dissolving of wood parenchyma clusters in such
a manner that wood tissues are transformed into resin.

Another theory ^ contradicts the first with the following
statements : " First, the pitch pockets in the very newest annual

* Communicated by the Director of the Forest Products Laboratory.

' H. Mayr in " Das Harz dcr Nadelholzer, etc," pp. 36-40.

Vol. 188, No. 1 124— 18 245

Digitized by VrrOOQlC

246 J. R. Watkins. [J.F.I.

ring are lined with parenchyma just the same as those in wood
over a hundred years old; there are no pitch pockets whose
parenchymal lining is entirely dissolved away. Second, the pitch
pockets are formed at a time and in a surrounding structure in
which all processes are engaged in the direct opposite of disso-
lution ; that is, in cell formation and reproduction ; namely, in the
cambium and during the cambial activity. The pitch pockets are
filled with resin from the very first moment of their origin, even
before the isolation parenchyma is fully formed. Third, fir
(Abies) and arbor vitae have abnormal parenchyma, like the
spruce, but in neither of the first named species does one ever
find a pitch pocket, since pitch pockets stand in a causal relation
with resin ducts, which latter, as is well known, are absent in
fir (Abies) and arbor vitae.

** There remains, therefore, for the origin of pitch pockets,
only the one explanation, that at the time of the cambial activity,
resin is squeezed from the horizontal canals into cambial layers,
which having been split thereby, are entirely separated for a cer-
tain extent of their surface by the outpouring of resin. This
resin, gushing out into the soft, thin walled and as yet uncom-
pleted layers, kills the neighboring cells, which then collapse.
There then begins on the part of the more distant parenchymal
cells, an inner overgrowth by means of the formation of proud-
wood parenchyma, which isolates the resin which has poured out
and in this way renders it harmless. The resin is squeezed into
the cambial layers with such force that at this point a considerable
expansion of the very thick bark results.

"It is difficult to determine what causes the pathological
exudation of resin from the horizontal canals into the growing
cambial layer. It is well known that, on account of the turgidity
of the sapwood layers, the resin in the resin ducts is under very
high pressure. The only way in which resin is made use of in
the case of the spruces and pines is by pressure exerted upon the
resin by the juicy sapwood. This is the only force which is able
to overcome the resistance of the exceptionally fine capillaries
(resin ducts). Wherever the tension due to the changing tur-
gidity of the structure changes most rapidly, one finds the most
pitch pockets.

" Because of this fact pitch pockets are most frequently found

Digitized by

Google

Aug.,1919.] Pitch Pockets. 247

in the vicinity of branches from the main trunk. On account of
these branches the ascending water current, which is deflected
from the main course at an angle, is dammed up. Those trees
which stand alone, and are therefore subjected to all extremes
of temperature and humidity, are noticeably richer in pitch
pockets than trees which have grown up surrounded by the
forest."

Another theory is that the tree is wounded by means of
some external force. The resin then flows to the wound, where
it assists in protecting the surface against drying out until it
can be healed by an overgrowth of proud wood.

TESTS OF THB BFFBCT OF PITCH POCKBTS ON THB STRBNGTH OF
AIRPLAHB WIHO BBAMS.

One investigator made a considerable number of tests of the
effect of pitch pockets on small test specimens. He Considered

Pig. I.

Length 8 inches, width iH inches, depth ^ inch. Showing pitch pockets and resin flecks
in a piece of white pine.

that pitch pockets were evidence of a diseased condition of the
wood. He also recommended that inspectors reject wood with
very large pockets, and in the case of wood with pockets that are
smaller but exceed i by J^ inch in dimensions special attention
be directed to the grain, and all resin-pocketed wood showing
slight general waviness or slight general obliquity of grain be
rejected. He states that pitch pockets of i by J^ inch in dimension
are not in themselves a cause of weakness and for this and other
reasons the position of the visible pockets of this size on a finished
airplane part is not of paramount importance. These tests were
made in England on " silver spruce," presumably Sitka spruce.
The theory that pitch pockets are merely evidence of a diseased

Digitized by

Google

248

J. R. Watkins.

[J.F.I.

condition seems untenable. In the many thousands of tests of
various coniferous specfes made at the Forest Products Labora-
tory there has been no evidence that the presence of pitch pockets
is indicative of a disease which weakens the wood.

During the early part of the war the rejection of wing beams
and other important parts because of the presence of pitch pockets
was quite large.

There are about 20 inspections of each beam and strut from
the time it enters the mill until it goes into the plane and each
inspection eliminates a fair percentage of the material. Follow-
ing is a table of data compiled during one month by an inspector
in a plant making DH-4 wing beams :

Number and Percentages of

DH-4 ^ing Beams
Final Inspection.

Rejected for

Various Causes at

Cause for
Rejection .

''Spi-

ral

Grain

Diag-
onal
Grain

Dip

Knot

Pitch
Pocket

Warp

Check

Dam-
age

Wind
Break

Glue
Fail-
ure

Dote

Number re-
jected

30s

138

218

Per cent, of
total num-

ber re-
jected

a8.8

1.5

9.2

7.6

13.0

6.2

20.0

5.6

1.7

0.8

Per cent, of
total num-

ber in-
spected . . .

4.4

0.2

1.4

I.I

2.0

0.9

3.1

0.8

0.2

0.1

Total Beams Inspected = 7016
Total Beams Rejected = 1060
Per cent. Rejected =15.1

This inspection was of finished beams and the table does not
indicate the percentage rejected before they had reached this stage.

At the suggestion and with the cooperation of Captain O. P.
M. Goss of the Spruce Production Division, a series of tests to
determine the effect of pitch pockets of various sizes located in
different parts of Douglas fir wing beams was undertaken at the
Forest Products Laboratory of the United States Forest Service,
Madison, Wisconsin. Sixty pairs of Douglas fir beam blanks
2 by 4 inches by 7 feet were selected by Captain Goss at the mills. It
was the intention in selecting these that one beam of each pair
should be entirely free from pitch pockets and that the other should
have pitch pockets in certain parts of the beam. Blanks giving

Digitized by

Google

Aug., 1919- ]

Pitch Pockets.

249

promise of filling these qualifications were selected and shipped
to the laboratory. The two beams of each pair were taken from
the same height in the tree and at the same distance from the pith,
that is, from the same annual rings of growth.

On arrival at the laboratory this material was carefully kiln
dried to about 10 per cent, moisture. The blanks were then
routed to the I-beam form shown in Fig. 2 for test in bending
over a span of 6 feet with loads at the third points of the span.

Fig. 2.

TYPICAL FAILURES OP BEAMS IN GROUP I.

TYPICAL FAILURES OF BEAMS IN GROUP 2.

TYPICAL FAILURES OF BEAMS IN GROUP 3*

Pitch pockets and their influence on the mechanical irropertieB of Douglas fir airplane
wing beams. Showing typical failures of tested beams with pitch pockets in various parts.

These beams were 2^ inches high by 1 5^ inches wide with ^-inch
webs and flanges. A length of 3 inches was left unrouted at
each support and each load point. Pitch pockets in some of the
blanks were eliminated in the routing.

Beams were divided into groups i, 2, and 3.

Group I included beams havijig pitch pockets in the com-
pression flange and between load points. Group 2 included beams

Digitized by

Google

250

J. R. Watkins.

[J.F.I.

having pitch pockets in the tension flange. Group 3 included
beams having pitch pockets in the web and between support and
load point. Each beam containing pitch pockets had a mate free
from pitch pockets selected as previously described and tested
in exactly the same manner.

Fig. 2 shows typical failures of beams of each gfroup. The
numerals'"!" and ** 2 " indicate the order in which failures
occurred.

Group /. — The first failure of all the beams in this group was
by compression, or buckling at the pitch pocket. This shows con-
clusively that the pitch pocket had a weakening effect and was the
cause of failure.

The following table gives the results of tests on individual
beams of this group. The strength properties of each beam are
given as a percentage of the same strength property of the beam
matching it. The matched beam was free from pitch pockets
or other defects affecting its strength.

Table I.

Dimension of Pitch

Pocket in inches

Modulus

Modulus of

Work to Maximum

Beam No.

of
Rupture

Elasticity

Load

Per cent.

31 p

1/16

3/4

22 p

l/«

106.5

33 p

1/16

lOI.O

100

37 P

1/8

I 1/4

98.5

*^l

1/16

97.5

17 p

1/8

I 1/8

99.5

35 p

1/8

29 p

1/8

I 1/4

L = length of pitch pocket.

W = width of pitch pocket as seen on face of beam.
D =» depth of pitch pocket, ». «., distance it extends into beam.

All beams in this series had the annual growth rings hori-
zontal in the beam, consequentiy, W is the radial and D the tan-
gential (to the annual rings) dimension of the pitch pocket.

Beams from which the pitch pockets were eliminated in rout-
ing were also tested and compared to other clear beams matched
to them in the same way as clear beams were matched to beams

Digitized by

Google

Aug., 1919] Pitch Pockets. 251

with pitch pockets. There were 80 clear beams matched in pairs
in this manner. Data from these tests are of assistance in inter-
preting the results given in Table I. These data show that
" matched " pieces differ from each other even when both are
free from defects.

Modulus of Modulus of Work to

Rupture Elasticity Maximum Load

Average ratio of strength property of
a clear beam to that of another clear

beam matched to it 990 .988 .996

Probable deviation of individual ratio

from average 044 .046 .111

The figures on " probable deviation " indicate that with
material selected and matched, as in the present instance, a piece
which is clear of defects will in one case out of four be expected
to be no more than 94.6 per cent, as strong in modulus of rupture
as its mate (also free from defects). The corresponding figures
for the other properties are modulus of elasticity 94.2 per cent.,
work to maximum load 88.5 per cent.

From this it is seen that two of the four pieces with 3-inch
pitch pockets fall below their mates by an amount which would be
expected to be found somewhat less frequently than one time out
of four in the case of pieces free from defects. The piece with
a 2-inch pitch pocket falls well within this limit for modulus
of rupture and work to maximum load. It will be noted that the
damage from 5-inch and 6-inch pitch pockets is quite serious in
beams of this size.

Group 2 — Pitch Pockets in Tension Flange and Between Load
Points. — The pitch pockets in this group were not greater in length
than four inches and in one case only did the line of failure pass
through the pitch pocket.

Group 5 — Pitch Pockets in Web Between Support and Load
Point, — Beams in this group were tested to ascertain the effect of
pitch pockets on the strength in horizontal shear.

The fact that in beam No. 55 (see Fig. 2) the horizontal shear
failure passes through the pitch pocket and the further fact that
this beam failed at a lower load than did its mate may be taken
as an indication that a pitch pocket of this length (4 inches)
constitutes a weakening in horizontal shear.

The conclusions reached from these tests are that :

Digitized by

Google —

252

J. R. Watkins.

[J.F.I.

1. The effect of a pitch pocket is dependent on its size and
location.

2. The effect of small pitch pockets on strength properties is
probably much smaller than has been supposed.

While these tests were on Douglas fir only, there is no reason
to suppose that the results are inapplicable to other species.

The tests are not sufficiently numerous to fix definite limits to
the size of pitch pockets which may be permitted in different parts
of various airplane members. In fact, it may easily be seen that

Fig. 3.

OUTER
QUARTER
OF FLANGE--

i T

\ \

.r^TiX

*• -*

—if

1
■ 1

a very large number of tests would be required to cover the pos-
sible combinations of size, character and location of such pockets.

The following suggested general specifications for wing beams
of I-section (solid or built-up) are based not only on the tests
described above but on many years' observation by members of
the Forest Products Laboratory of the effect of pitch pockets
and various other defects on strength properties and on failures
under test.

(a) At points where the computed stress multiplied by the
loading factor is equal to the maximum allowable stress the beams
must be entirely free from pitch pockets.

(&) At points where the computed stress multiplied by the
loading factor or so-called " factor of safety " does not exceed

Digitized by

Google

Aug., iqiq] Pitch Pockets. 253

90 per cent, of the maximum allowable stress pitch pockets ij/^
inches in length and not to exceed % inch in width or depth may
be allowed in any part of the section, except the outer quarters
of the flange — provided they do not cause a slope of grain steeper
than I in 25 in the outer quarters of the flange. No pitch pockets
to be allowed in outer quarters of flange.

(c) At points where the computed stress, multiplied by the
loading factor, does not exceed 70 per cent, of the maximum
allowable stress, pitch pockets 2 inches in length and not to
exceed % inch in width or depth may occur any place in the
section, except in the outer quarters of the flange — ^provided they
do not cause a slope of grain steeper than i in 20 in the outer
quarter of the flange. No pitch pockets to be allowed in outer
quarters of flange.

(d) At points where the computed stress, multiplied by the
loading factor does not exceed 50 per cent, of the maximum allow-
able stress, pitch pockets, i J4 inches in length and % inch in width
or depth may occur in the outer quarters of the flange and pitch
pockets 3 inches in length and 54 inch in width or depth may
occur in any other portion of the section — provided they do not
cause a slope of grain steeper than i in 15 in the outer quarters
of the flange.

(e) Pitch pockets in the web may not be closer together than
20 inches; if in the same annual ring they may not be closer
together than 40 inches. In other portions of the section these
distances may be 10 and 20 inches, respectively.

Asphalt in the United States. (U. S. Geological Survey, Press
Bulletin, July, 1919.) — Asphalt is widely known and has long been
extensively used in road construction, but in recent years many
producers of asphalt and allied substances have successfully mar-
keted their products for other uses.

Asphalt is most largely used in this country in paving city
streets and country roads, and, though its utilization in road
building in 1918 was restricted chiefly to the maintenance of exist-
ing pavements and to new construction at cantonments, shipyards,
and elsewhere in war work, a larger quantity of paving asphalt,
binder, filler, road oil, and flux was made from petroleum and
crude native asphalt and sold last year than had been sold in any
one year preceding the war.

The uses of asphaltic materials, including both native asphalt

Digitized by

Google

254 Current Topics. [J.FI.

and asphalt made from petroleum, as well as gilsonite, grahamite,
and elaterite, in buildings and other structures are manifold. As
they are elastic, antiseptic, acid-resistant, and moisture proof,
these materials are being widely employed for use in flooring and
roofing, in waterproof coating, and in electric insulation, as well
as in the manufacture of varnish, paint, and putty. Although
these materials have been marketed for relatively few years they
are in general demand among contractors and engineers and their
use is rapidly increasing.

Gilsonite, the purest known hydrocarbon, has found great
favor in the rubber industry. As pure rubber is sensitive to heat
and cold it can not be used advantageously for making products
that are exposed to extreme temperatures, but when it is mixed
with gilsonite and the mixture is vulcanized the rubber under-
goes changes in composition that enable it to resist variations in
temperature as well as oxidation. The product of this mixture,
which is called mineral rubber, is well adapted to outdoor use,
and the demand for it is increasing.

Ozokerite, a native paraffin, is utilized in the manufacture of
leather polish, sealing wax, electrotypers' wax, candles, electric
insulation, carbon paper, and ink. Prior to the war all the ozo-
kerite used in this country was imported, chiefly from Galicia,
but when that source of supply was cut off a search was made for
deposits in the United States, and this hydrocarbon first entered
the market from domestic deposits in 1916. Most of the output
in 1918 was used as an acid-proof coating for electrotypers' plates.

American Chemical Society. {A. C. S. News Service, July 14,
1919.) — The fifty-eighth meeting of the American Chemical So-
ciety will be held in the city of Philadelphia from September 2nd
to 6th inclusive. The first general meeting will be held on Wednes-
day morning, September 3rd. One of the features will be the first
session of the newly organized dye section. There will be a joint
session of this section with the Division of Industrial Chemists
and Industrial Engineers to consider a proposal to revise the
patent laws." It has been suggested that the charging of a
nominal annual renewal fee would compel many patentees to
exploit their patents rather than to permit them to remain unde-
veloped for many years. Special arrangements have been made
to give to all delegates to the convention access to the various
chemical plants in and around Philadelphia. An opportunity to
view the large munition works will also be given the visitors.

Digitized by

Google

RECENT PROGRESS IN THE MANUFACTURE OF
GLASSES FOR PROTECTING THE EYE FROM
INJURIOUS RADIATIONS.*

W. W. COBLENTZ, Ph.D.

Associate Physicist, Bureau of Standards.

The old saying that it is an ill wind that blows no one good,
is well illustrated in the manufacture of optical glass.

One of the chief requirements in the manufacture of optical
instruments is a colorless glass. Iron is the most common
substance which causes discoloration in, and hence diminishes,
the transmission of optical glass. On the other hand, iron impuri-
ties in glass have a marked absorption in the infra-red, the
maximtun being at about ift. This property may, therefore, be
utilized in the manufacture of glasses for protecting the eye
from infra-red rays.

Although it has not been definitely proven that infra-red rays
are injurious to the eye, there seems to be a feeling that protec-
tion from these rays should be provided. Fortunately this can
be done easily and cheaply. And now the most pampered can be
provided with glasses which not only give protection from rays
which are known to be injurious, but also supply the most exact-
ing demands as to color, etc.

It is of interest to consider the transmissive properties of
various glasses which, used separately or in combination, protect
the eye from injurious radiations — ^particularly from ultra-violet
rays.

The ideal glass would be one which absorbs all the ultra-
violet and infra-red, and transmits only the visible rays, by an
amount sufficient to prevent irritation and injury to the eye.

Four years ago the question of providing glasses for pro-
tecting the eye from injurious radiations was practically new and
untouched. At that time the feeling was expressed ^ that : " It
appears as though in the near future glasses fulfilling every

* Communicated by the Author.

* Jour. Franklin Institute, May, 1913.

255

Digitized by

Google _

256 W. W. COBLENTZ. [J.F.I.

requirement will be obtainable, and it speaks well for American
enterprise to be willing to spend a few dollars in attempting to
produce devices for safeguarding the health and contentment
of the public."

In the meantime, this prediction has become a reality. The
subject of eye protection has become national in importance, and
manufacturers of eye protective glasses are meeting the most
stringent requirements.

Fig. I.

z
o
Jo

£
in

1 — LAU i^^-*^ '^ '

.0 .5 1.0 Z.O 3.0 4.0 S/JL

The variety of ways in which various manufacturers of eye-
protective glasses fulfill these requirements, will be noticed in con-
nection with the transmissive properties of various glasses, which
will now be discussed. In most cases these glasses were about
2 mm. in thickness. More detailed data may be obtained by
consulting the original paper.^

Colorless Glass. — It is of interest to note the characteristics

• Bull. Bur. Standards, 14, p. 663, 1918.

Digitized by

Google

Aug., 1919.] Progress in Manufacture of Glasses.

257

of optically colorless glass. Curve A, Fig. i, g^ves the trans-
mission ojf a sample of white crown glass which transmits ultra-
violet to about 0.3/1 and infra-red to about 4.8/t. The shallow
absorption bands at 2.9/1 and 3.6/t are characteristic of glasses.

The presence of iron impurities produces a marked change
in the transmission of a glass with an absorption band at about
i.i/t. This is illustrated in curves A and C of Fig. 2, which

Fig. 2.

90 r

z
o

2 50

40
30
20

10
P

0.0

1.0

2.0

3.0

4.0

5.0 /t

gives the transmission of window glass. Viewed edgewise, such
glass appears tinged green.

Red Glass. — Curve B, Fig. i, shows that red glass absorbs
the ultra-violet and most of the visible rays. But it affords
practically no more protection from infra-red rays than does
clear glass.

Amber Glass. — As illustrated in Curve B, Fig. 2, amber
glass absorbs the ultra-violet and some of the visible spectrum.
Iron impurities produce an absorption band at i.i/i. Aqueous
solutions of iron alum have an absorption band at about i/*.

Green Glass, — Curves A, B and C, Fig. 3, show that green

Digitized by

Google

258 W. W. COBLENTZ. [J.F.I.

glass is opaque to the ultra-violet and has a wide absorption
band in the region of i/*. In combination with other, glasses, it
affords suitable protection from injurious rays.

Blue Glass, — Curve A, Fig. 4, gives the transmission of a
sample of cobalt blue glass. In spite of the fact that blue glasses
transmit ultra-violet, they are used in some high temperature work.
Combined with a deep amber, red or green glass, it affords pro-
tection from injurious rays. For example. Curve C, Fig. 5, gives

Fig. 3.

z
o

i
in

z
<

0.0 1.0 Z.O 3.0 4.0 yu.

the transmission of a combination of several red and blue glasses
used in arc welding. Curve D, Fig. 5, gives the transmission of
a combination of a flashed red, a green and a blue glass used in
oxy-acetylene welding. These two combinations were found to
reduce the intensity of the visible rays by a suitable amount, and
they afford proper protection from the infra-red and especially
the ultra-violet. (In these two curves, C, D, Fig. 5, the trans-
missions are double the values indicated on the scale. )

Sage Green and Blue Green. — ^Two excellent glasses for

Digitized by

Google

Aug., 1919.] Progress in Manufacture of Glasses.

Fig. 4.

259

50
40

z
<
0^ 30

f 1

(

•

^.^ I 1 1 I 1 T^ 1

0.0

1.0

2.0

3.0

4..0

5l0/i

40% r-

20 -

S 15

Fig. 5.

Digitized by

Google

260 W. W. COBLENTZ. [J.F.I.

absorbing the ultra-violet and infra-red are Crookes' ferrous
sage green (American Optical Co., Curve B, Fig. 4), and Corning
C, 124 J. A,, Curve C, Fig. 4.

Gold Leaf. — A thin film of gold on glass (obtained from
A.O.C; see Curves A and B, Fig. 5) eliminates the infra-red
and ultra-violet, and by selecting the proper density provides also
protection from visual rays.

Black Glass. — Ordinary " smoke " glasses are good for out-
door wear, but they do not give sufficient protection when working
near sources of intense ultra-violet radiation.

Fig. 6.

z
o

in
(0

r
to

z
<

I-

0.0 1.0 2.0 3.0 4.0 S.OfJL

Judging from the small number of " black " glasses sub-
mitted for test, in comparison with other glasses used in oxy-
acetylene welding and cutting, it would appear that the so-called
deep " black '' glasses are not used extensively.

Noviweld. — This is a commercial eye-protective glass (Com-
ing Gl. Works) which effectively absorbs the ultra-violet and
infra-red rays. The transmissive properties of various shades
are shown in Fig. 6.

Dyes. — Attempts have been made to use dyed celluloid films
instead of colored glass for protection against harmful radia-
tions. In this manner it seems feasible to absorb the ultra-
violet and visible rays. But the writer knows of no dye which
has marked absorption throughout the infra-red. As shown in
Curve C, Fig. i, a sheet of celluloid which is dyed so as to be

Digitized by

Google

Aug., 1919.] Progress in Manufacture of Glasses. 261

opaque to the visible and ultra-violet, is quite transparent in the
infra-red.

The published data of others * shows that dyes {e,g., green and
violet dyes) which absorb the yellow and red become quite trans-
parent in the infra-red. Hence, unless a dye is found which
absorbs the infra-red, the outlook for sut^tituting dyed films for
colored glasses, for absorbing the infra-red, is not very
encouraging.

The foregoing is a brief description of the characteristics of
glasses readily obtainable, Which singly or in combination afford
protection from injurious radiations.
Washington, D. C, April 15, ipig.

*Pfund, Zeitschr. Wiss. Photog., 12, p. 341, 1913; Johnson and Spence,
Pkys. Rev. (2). 5, p. 349. IQIS-

Preciou^Stones in the United States. (U, S. Geological Sur-
vey, Press Bulletin, July, 1919.) — ^The value of the precious stones
annually produced in the United States from the beginning of this
century to 1914 has been about one-third of a million dollars. In
1914 and in every year since, the annual value of the output has
dropped considerably, and in 1918 it dropped to $106,523, the lowest
reported since the United States Geological Survey began to collect
statistics of gem production, in 1883, with the single exception of
1896, when it was $97,850.

The report on the production of precious stones in 1918, just
published by the Survey, ascribes the decrease in the value of the
precious stones produced to the military enlistment of many gem
miners, the general scarcity of labor, and the poor market.

The output consisted chiefly of the sapphire variety of corun-
dum, which is nearly all used as mechanical bearings in watches
and other instruments that require practically nonwearing fric-
tionless bearings. Other less valuable and softer minerals used
for this purpose are garnet and some forms of hard, compact
silica, known as agate and chalcedony. The annual value of
the output of the four gem minerals, corundum, quartz, tour-
maline, and turquoise, amounts to over four-fifths of the total
value of all the precious stones produced in the United States.
Montana, Nevada, California, Colorado, Maine, and Arizona
are the chief gem-producing States, but from 20 to 30 States
annually report some production.

Several relatively large diamonds were found in Arkansas in
19^8, notably a canary-colored octahedron weighing nearly 18 carats
and a number of smaller stones weighing several carats each.
Vol 188, No. 1 124— 19

Digitized by

Google

262 Current Topics. [J- F- 1-

The value of all the diamonds produced in the United States,
however, in no year exceeds a few thousand dollars.

The report also records the finding of two large diamonds in
South Africa, weighing about three ounces each. It is estimated
that about half the diamonds in the world are owned in the United
States and that their value is over a billion dollars. With the
elimination of competition from German Southwest Africa 95
per cent, of the world's production of diamonds will be under the
control of the De Beers Consolidated Mines Co. and its selling agents.

The report gives a short list of the industrial uses of precious
stones of gem quality and full descriptions of the Iceland spar
variety of calcite and of optical fluorite, states the special uses
and necessary qualifications of the material, and includes lists
of buyers.

The report on the production of precious stones in 1917 con-
tains a full list of gem names, each followed by the name of the
mineral species to which the gem belongs. A second list gives
names of the mineral species, each followed by all the names of
the corresponding gem.

Central-Station Heating in Detroit. J. H. Walker. {The
American Society of Mechanical Engineers, Spring Meeting, June,
1919.) — The general problem of the utilization of the heat ordinarily
discharged to the condensing water in a central electric generating
station is discussed. The impossibility of its complete utilization for
the purpose of heating buildings and the difficulties in the way of
even its partial utilization are pointed out, with particular reference
to conditions existing in Detroit, Michigan.

The development of the central heating system of the Detroit
Edison Company is traced, showing how the use of exhaust steam
for heating was abandoned in favor of live steam. The reasons why
it is more commercially expedient under the existing local condition
to supply live steam to the heating system and to generate all electric
current in the condensing stations are also fully brought out.

The paper also describes some interesting features of the central
heating system in Detroit, such as the boUer plants, distributing
system, underground construction of pipes and tunnels, consumers'
installations and meters. Special mention is also made of distribu^
tion losses, condensation return lines, and the method of transmit-
ting steam through feeders at high velocities and with large pres-
sure drops.

The paper concludes with a discussion of the advantages of cen-
tral heating service and of the obstacles to its wider use. It also
points out the possibility of operating individual plants in combina-
tion with the central plant.

Digitized by

Google

NOTES FROM THE U. S. BUREAU OF STANDARDS.*

SOME OPTICAL AND PHOTOELrECTRICAL PROPERTIES
OF MOLYBDENITE.'

By W. W. Coblentx and H. Kahler.

[abstract.]

This paper gives data on the transmissivity and the reflec-
tivity of molybdenite ; also data upon its change in electrical con-
ductivity, when exposed to thermal radiations of wave-lengths
extending from the ultra-violet into the extreme infra-red.

The effect of temperature, humidity, intensity of the exciting
light, etc., upon the photoelectrical sensitivity of molybdenite was
investigated.

It was found that :

( 1 ) Samples of molybdenite, obtained from various localities,
differ greatly in sensitivity.

(2) There are maxima of sensitivity in the region of 0.73/*,
.8s>, I. 02a*, and i.8a*.

(3) There is no simple law governing the variation in the
photoelectric response with variation in intensity of the radia-
tion stimulus.

(4) The increase in photoelectric current, with increase in
intensity of the incident radiation is greatest for infra-red rays.
It is greatest for low intensities of the exciting light and it is
greatest on the long wave-length side of the maximum.

(5) The photoelectric sensitivity increases with decrease in
temperature. At 70° C. the bands at 1.02/* and 1.8/* have prac-
tically disappeared. On the other hand, at liquid air temperatures,
the greatest change in electrical conductivity is produced by radia-
tions of wave-lengths between 0.8/* and 0.9/^.

Unlike selenium, molybdenite appears unique in being photo-
electrically sensitive to infra-red rays, extending to about 3/1*.

♦ Communicated by the Director.

* Scientific Paper No. 338.

263

Digitized by

Google

264 U. S. Bureau of Standards Notes. iJ- F- 1-

A STANDARDIZED METHOD FOR THE DETERMINATION OP

SOLIDIFICATION POINTS, ESPECIALLY OF NAPHTHA-

LENE AND PARAFFIN.'

By R. M. Wilhelm and J. L. Finkelstein.
[abstract.]

This paper, after a brief treatment of the definitions of melt-
ing and freezing points both of pure substances and of mixtures,
describes a method of making solidification point determinations
of naphthalene. This method was recommended at a conference
of Bureau of Standards and U. S. Customs officials and is based
on the well-known cooling curve or constant temperature method.
The method is shown to be applicable to the determination of the
freezing points of paraffin and other substances.

THE STANDARDIZATION OF THE SULPHUR BOILING POINT/

By E. F. Mueller and H. A. Burgess.
[absteact.]

This paper describes experiments made to complete the data
which are required for the standardization of the sulphur boil-
ing point as a thermometric fixed point. The precision attainable
in calibration of resistance thermometer^ at the sulphur boiling
point is so much higher than the accuracy of the gas thermometer
determinations of the temperature that it was considered desir-
able to standardize the temperature corresponding to normal at-
mosphere pressure by definition at 444.^60, and the data from
which this figure was deduced are given.

Experiments were made to determine the effects of type of
radiation shield, the type of boiling apparatus and purity of sul-
phur, upon the temperature assumed by a resistance thermometer
in the sulphur yapor. The conclusions reached were that if a
radiation shield is to be effective, its inner surface should be a
good radiator, that, witfam wide limits, the temperature is inde-
pendent of thie type of bdiHAg apparatus used, and that sulphur
of a high degree of purity, which is however readily obtainable,
should be used.

The relation between the vapor pressure of sulphur and the

* Scientific Paper No. 340.

• Scientific Paper No. 339.

Digitized by

Google J

Aiig.,1919.] U. S. Bureau of Standards Notes. 265

temperature, over the pressure range from 700 to 800 mm. was
determined with a precision of o.°oi or better. The result of this
work is the equation :

^ = 444.°6o-f 0.0910 (p-76o)-o.oooo49 (p-760)* where / is
the temperature in Centigrade degrees, assumed by a properly
shielded resistance thermometer in the standard form of sulphur
boiling apparatus, and p is the pressure, expressed in equivalent
millimetres of mercury at 0° and under standard gravity (^ =
980.665). In an appendix are given the specifications for a pro-
posed standardization of the sulphur boiling point.

METALLIC COATINGS FOR THE RUST-PROOFING OF
IRON AND STEEL.'

[abstract.]

Steel is protected against corrosion in a great variety of
ways, including metallic and related coatings, paints, lacquers, var-
nishes, enamels, etc. The circular* deals wiA the various types
of metallic coatings, including those closely related in their nature
and method of production (oxide and similar coatings). The
methods of application and characteristics of the different metal
coatings are discussed and it i$ shown that zinc, because of its
electro-positive nature with respect to iron, is the metal to be
relied upon when protection against corrosion is the prime con-
sideration. Other considerations, e,g., freedom from toxic effects,
e.g., for food containers, often lead to the choice of some metal
other than zinc for a coating.

The structure and uniformity of distribution of the different
classes of zinc coatings are discussed and their bearing upon the
behavior in service is pointed out. Of the various methods which
are used for the testing of coated materials, the " salt spray " test
is by far the most satisfactory. The articles to be tested are ex-
posed to a fine mist of a saturated salt- solution and the length
of time that they successfully withstand this severe exposure is
a fair index of the service life that may be expected for. the speci-
men. This test while not entirely satisfactory is the best which
has yet been suggested.

A series o.f. recommendations, concerning. the choice .of. pro-
tective metallic coatings for .various types pf works is given, to-
gether with a good working bibliog raphy of the subject.

•Orcular No. 80. ~ ~ ' ' ' ' ^'- '

Digitized by

Google

266 U. S. Bureau of Standards Notes. IJFI.

LEAKAGE RESISTANCE OF ELECTRIC RAILWAY ROADBEDS
AND ITS RELATION TO ELECTROLYSIS/

By E. R. Shepard.
[abstract.]

Technologic Paper 127 of the Bureau of Standards, entitled
** Leakage Resistance of Electric Railway Roadbeds and its Rela-
tion to Electrolysis," by E. R. Shepard, Electrical Engineer, gives
the result of more than three years of electrical resistance meas-
urements on different types of roadbeds. Electrolytic damage to
underground piping systems is caused from the escape of current
from the rails of electric lines and the resistance of the roadbed
is an important factor in the amount of current which may escape.

Short sections of fourteen common types of roadbeds were
constructed on the grounds of the Bureau of Standards and resis-
tance measurements under varying weather conditions were car-
ried on for a period of three years. Some measurements were
also made on a number of city lines in and about Washington, both
open track and several types of roadbed in paved streets being
investigated. Through the cooperation of the United States For-
est Products Laboratory at Madison, Wisconsin, measurements
were also made on several sections of test track on the Chicago,
Milwaukee and St. Paul Railway where railroad ties subjected to
several different kinds of preservatives were employed. The re-
sults of these measurements are given in tabular and graphical
form, and the following conclusions have been drawn :

I. Roadbeds constructed with solid concrete ballast and vitri-
fied brick or other non-porous pavements have a low leakage
resistance to earth which is affected only moderately by seasonal
and weather changes. There is little difference between wood
and steel ties in their effect on the resistance of roadbeds of this
kind. Insulation is not of practical value in reducing leakage cur-
rent from such roadbeds. The resistance of single roadbed of
this type is from 0.2 to 0.5 ohm per 1000 feet, under ordinary
conditions, but may be two or three times this when the ballast is
frozen to a depth of i foot or more. For double roadbed of this
type the resistance is approximately 70 per cent, of that for single
roadbed, or the leakage from double track would be about 40 to
50 per cent, greater than from single track.

• Technical Paper No. 127.

Digitized by

Google

Aug., 1919] U. S. Bureau of Standards Notes. 267

2. Roadbeds constructed with a foundation of clean crushed
stone under concrete paving base have a much higher resistance
than roadbeds with a solid concrete ballast. In the case of the
experimental roadbed the ratio was found to be about 3 to i.
Roadbeds with a full crushed stone ballast and a Tarvia finish
have a very high leakage resistance which is of the order of 2 to 5
ohms per. 1000 feet of single track. The leakage from a double
roadbed of this type and other high-resistance types is from 80
to 100 per cent, greater.

3. The resistance of earth roadbed in which the ties are im-
bedded and therefore kept in moist condition is much lower than
that of open construction roadbed, being from i to 13^ ohms per
1000 feet of single track under normal conditions and consider-
ably more when the ground is frozen.

4. The resistance of roadbeds of open construction is subject
to wide variation depending upon the condition of the ties and
ballast. In very dry weather with good ballast the resistance will
be 10 to 15 ohms or even more per 1000 feet of single track, but
in wet weather it will drop to from 3 to 5 ohms. Cinder, gravel
and particularly crushed stone, when used as a ballast in open-
track construction, produce very high-resistance roadbeds. Earth
has a tendency to keep the ties moist and therefore to increase the
leakage. Open-construction track is often considered to be insu-
lated from the earth, but this is not strictly true. Assuming a
potential difference between the track and the earth of 5 volts and
a leakage resistance of 10 ohms per 1000 feet the total leakage
per mile would be 2.64 amp. This small leakage current would
not ordinarily be harmful to underground structures in the vicin-
ity of the track.

THE CONSTITUTION OP ALUMINUM AND ITS LIGHT ALLOYS
WITH COPPER AND WITH ALUMINUM."

By P. D» Merica, R. G. Waltenberg and J. R. Freeman, Jr.
[abstract.]

The temperature-solubility curves of CuAlg and of Mg^-
AI3 in aluminum were determined by the method of annealing and
microscopic examination. Aluminum dissolves about 4.2 per cent.

•Scientific Paper No. 337.

Digitized by

Google

268 U. S. Bureau of Standards Notes. [J- F- X-

of copper as CuAlg at 525° C and about 12.5 per cent of mag-
nesium as Mg4Al8 at 450° C.

The solubility of both compounds decreases with decreasing
temperature. At 300° C. aluminum dissolves only i per cent of
copper as CuAls and slightly less than 5.9 per cent, of magnesitun
as Mg4Al8.

The structural identification of the various constituents,
FeAlg, CuAlg, Mg4Al8, found in alloys with magnesium and
with copper is described, and a constituent is noted in all light
aluminum alloys containing magnesium which is believed to be
MgaSi.

The solubility of iron as FeAlj in aluminum is at all tempera-
tures less than o. 1 5 per cent.

Small amounts of silicon up to from 0.12 to 0.20 per cent, are
dissolved by aluminum at the eutectic temperature but are repre-
cipitated upon cooling corresponding to the diminished solubility
for silicon of aluminum at lower temperatures.

Silicon in the usual commercial amounts is probably present
as a compound of iron and silicon together with some aluminum.
The composition of this compound is not known, but it sep-
arates out with aluminum and FeAlg at an invariant point at
610° C.

Large Engine and Small Power. (National Engineer, vol.
xxiii, No. 7, p. 325, July, 1919O — ^The Savannah, the first ocean-
going ship to use steam engine propulsion (1819), shows the
difference between then and now of boiler pressures available,
so much so that comparatively large engines were needed to
develop what nowadays is considered small power. The engine
of the Savannah was equipped with a cylinder 40 inches in diameter
and 60-inch stroke, built by Stephen Vail, near Morristowni N. J.
The boilers were constructed to carry a steam pressure of 20 inches,
registered by a mercury gauge, and were built by Daniel Tod, of
Elizabeth, N. J. The paddle wheels could be folded up like a fan
and stored on deck when the sea was too rough for their use.
Although both sail and steam power was used, the vessel made,
on trial, ten miles with and against .tide in one hour and fifty
minutes. This equipment and performance of the Savannah and
that of the Maiiretania tells the story of achievement in marine
performance.

Digitized by

Google

NOTES FROM THE U. S. BUREAU OF CHEMISTRY.*

THE CONSTITUTION OF CAPSAICIN, THE PUNGENT
PRINCIPLE, OF CAPSICUM.'

By E. K. Nelson.

[abstract.]

Material for this research was prepared according to
Micko's method for the preparation of capsaicin. The best yield
obtained was 50 grams of capsaicin from 50 pounds of very hot
cayenne pepper.

Methylation of capsaicin produces methyl capsaicin, and oxi-
dation of this by means of alkaline potassium permanganate leads
to veratric acid. Hydrolysis under pressure breaks capsaicin down
into vanillyl amine (4-hydroxy-3-methoxy benzylamine) and a
decylenic acid. That the decylenic acid in the molecule of cap-
saicin does not possess a normal chain is proven by the fact that
on hydrogenation normal decylic acid (capric acid) is not
formed, but an isomeric decylic acid melting lower than capric
acid.

Capsaicin is therefore a condensation product of vanillyl
amine and a decylenic acid. The synthesis of substances analogous
to capsaicin is being undertaken, and will form the subject of a
later communication. Some of these substances already pre-
pared are extremely pungent.

THE ZINC CONTENT OF SOME FOOD PRODUCTS."

By Victor Birckner.

[abstract.]

Examination of the ash disclosed the presence of appre-
ciable quantities of zinc in many food products. Bakers' yeast,
wheat, oats, com, barley, rye, and rice contained from 415 to 15
mg. of zinc per 1000 grams of fresh substances. In ordinary

♦ Communicated by the Qiief of the Bureau.

* Published in /. Am. Chem. Soc, 41: 1115-21, July, 1919.
■ Published in / . Biol Chem,, 38: 191-203. June. 1919.

Vol. 188, No. 1124 — 20 269

Digitized by

Google

270 U. S. Bureau of Chemistry Notes. W- ^' ^•

market milk about 4.2 mg. of zinc was found per 1000 grams,
and in human milk from 6 to 14 mg. per 1000 grams. Practically
all the zinc in hens' eggs, amounting to about 0.005 per cent, of
the yolk, occurred in the yolk.

From its constant occurrence in the yolk of eggs as well as
in cows' and human milk, it is inferred that the element zinc
exerts an important nutritive function, the nature of which is not
at present understood.

Tumbler Switches. {Scientific American, vol. cxxi, No. 3,
P- 53* July 19, 1919.) — While the tumbler switch has long been
the standard in most countries abroad, the United States has
persistently stuck to the snap switch and the push-button switch.
Of late, however, the advantages of the tumbler switch have
come to be realized, and manufacturers have started in on the
production of such switches. Some of the designs offered are
typically English, while others are distinctly American in their
simplicity of design. The new switches of the tumbler type are
exceptionally attractive in appearance and convenient to use. A
single button operates the mechanism, which is of the quick
make-and-break variety. Incidentally, the tumbler switch is self-
indicating, the position of the lever indicating whether the switch
is " on " or " off " at a glance.

Air Pans for Driving Electric Generators on Airplanes. G.

Francis Gray, John W. Reed and P. N. Elderkin. {The Ameri-
can Society of Mechanical Engineers, Spring Meeting, June, 1919.)
— The authors describe the method employed by the Radio Develop-
ment Section of the War Department in testing air fans used for
driving the electric generators usually installed on airplanes for
radio communication. They also discuss at some length the various
types of air fans and present numerous photographs and curves
clearly illustrating the construction of the fans and their operating
characteristics.

The difficulty of the problem lay in designing a fan which would
turn at constant speed in the air streams of widely varying speed set
up by the airplane in flight. The various types of fans tested were ;
Fixed-blade fans of special blade shape; fixed-blade fans with wind
brakes centrifugally regulated; fixed-blade fans using a friction
clutch or a friction brake centrifugally regulated, and pivoted-blade
fans in which the pitch is centrifugally regulated.

Digitized by

Google

NOTES PROM THE U. S. BUREAU OP MINES.*

METHOD OP ADMINISTERING LEASES OP IRON ORE DB-
POSITS BELONGING TO THE STATE OP MINNESOTA.'

By J. R Pinlay.

At the request of the State Auditor of Minnesota the
Bureau of ^ines undertook an investigation of the methods of ad-
ministering State leases of iron ore deposits. As the material in the
report submitted is of great general interest it has been published
for the benefit of the mining industry in general. The State of
Minnesota owns 40,400 acres of land known to be ore-bearing,
containing 168,000,000 tons of iron ore of present commercial
grade. These ores are mainly leased under agreements that ex-
pire at the average date of 1952, under a royalty of 25 cents per
ton and an agreement that the lessee shall work the mines in a
manner which is customary in skilful mining. Two points are
therefore involved: whether the mines are actually being
so worked, and on what ores shall the State demand royalties.
The ores range in grade from 65 per cent, down to 30
per cent iron, average ore shipments are 56 per cent,
iron, and it is therefore practicable to mix higher grade
ores with lower grades, providing the latter are above the
limit of profit. The investigation shows that ores under 48 per
cent, iron- dry or 42 per cent natural are not profitable to work
under present conditions. Concentrating ores which run only 30
per cent, iron up to 50 per cent, iron is only an apparent exception,
since in this case it pays to add to the cost of production in order to
reduce the cost of transportation. Whether the ** paint rock,"
which averages about 50 per cent, iron, is an ore is a matter of dis-
pute between State officials and lessees. The conclusion of the
author is that under present conditions it cannot be considered as
ore, and its removal in underground operations is not justified. In
open cut operations it has to be removed anyway, and it can be
kept segregated in case it may eventuaMy prove of value. The

* Communicated by the Director.

* Technical paper 222.

271

Digitized by

Google

272 U. S. Bureau of Mines Notes. IJFI-

taconite or " iron formation " averages about 35 per cent. iron.
At the eastern end of the Mesabi range there is an area in which
the taconite has been so magnetized that its concentration by
magnetic processes is possible. At the present time the capital in-
vestment required to make this separation is too large compared
to the margin of profit, but it is not at all impossible that at some
future time the value of the product or the cost of construction
of the plant may be so altered as to make this material commercial
ore. The author is confident that enough ore is available in Minne-
sota to keep up shipments of the present grade for 30 years.
There is not much ground for anxiety as to the conserving of these
possible sources of future wealth. The ores are indestructible and
the great bulk of the formations are not likely to be so mixed by
mining operations as to become utterly inaccessible. In some in-
stances ores leased by the State at a royalty of 25 cents per ton
have been sub-leased at a higher royalty and it is not fair to the
people of the State for the operator to refuse to mine ore that
would meet the 25 cents royalty but will not meet the higher roy-
alty. This can only be met by negotiations between the operators
and lessees for modification of royalty conditions. The con-
clusion of the author is that the State lands, so far as the iron
mines are concerned, have all been well and properly administered.

ELBCTRODEPOSITION OP GOLD AND SILVER PROM
CYANIDE SOLUTION.'

By S. B. Christy.

Electrolytic precipitation of gold and silver from cyanide
solution would seem, on the face of it, not to offer any great diffi-
culty since the electro-plating of gold and silver is a well-de-
vQjoped art. But as a matter of fact, a great many practical diffi-
culties develop since the solutions resulting from the cyanide
treatment of ores are a rather complex mixture of salts, and no
really satisfactory substance has been found for the insoluble
anode that must be used. The precipitation of these metals by
the use of zinc shavings or dust is so relatively simple that their
electro-deposition has never come into general use, although a
patent for such a process was issued 20 years before the McArthur

•Bulletin 150.

Digitized by

Google

Aug., 1919] U. S. Bureau of Mines Notes. 273

and Forrest patent on the cyanide process of gold recovery ap-
peared. Meanwhile a number of processes for this purpose have
been patented. At intervals over a period of 20 years Professor
Christy studied the problem and took out a patent for a process of
his own in 1900. Like the other patented processes it, never came
into general use, but in the course of his investigations Professor
Christy performed an enormous amount of experimental work,
which is recorded in this monograph. This careful record of ex-
periments covering all phases of the subject under investigation is
of great value for reference for investigators in the field of elec-
trolytic deposition of metals.

ELECTRIC FURNACE LABORATORY EQUIPMENT AT
SEATTLE STATION, U. S. BUREAU OP MINES.

By Charles D. Grier.

The power supply e(}uipment of the electric furnace labora-
tory at the Seattle Station, which has recently been installed, con-
sists of two 140 kva. transformers and t^o duplex induction volt-
age regulators for supplying low tension current, and a three-panel
switichboard and bus bar system for its distribution. As different
furnaces are built to fit the needs of the various problems pre-
sented, connections can be made between the bus bar system and
the furnaces, and either single or two-phase power supplied at any
voltage between 35 and 484 volts.

The transformers and regulators are connected on the primary
side to a 2,500-volt line from the Mimicipal Power Plant The
secondary coil of each transformer is divided into four sections,
each of which has a normal voltage of 78 volts. The voltage of
each of the secondary coils of the regulators can be made anything
from 43 volts " boosting " to 43 volts "* bucking," according to
the relative position of the coils. Each transformer secondary
coil is connected in series with a secondary coil in one of the
regulators and it may be considered that the combination of each
transformer and. its regulator is a transformer with four coils,
each capable of delivering 450 amperes at any voltage between
35 and 121 volts.

On the switchboard are mounted high and low tension volt-
metres, ammetres for both phases, a power factor metre indicat-

Digitized by

Google

274 U. S. Bureau of Mines Notes. [JFI-

ing and recording wattmetres and a watthour metre. Various
switches permit connecting the transformers both on a single phase
or one on each of the two phases, on the primary side, and of con-
necting the secondary coils in multiple, series, or series-multiple.
The motors which operate the voltage regulators are controlled
by push-button switches on the board, so that control of the
furnace voltage twithin wide limits is eflFected by merely pressing
buttons on the switchboard, and changes through the extreme
range involve only two very simple switch changes.

The capacity of the equipment is a maximum when the
regulators are boosting the maximum. At such a time the rated
capacity is 435 kva. At the lowest voltage the capacity is 126 kva.
The apparatus is therefore capable of delivering as much power
as is used by small commenual furnaces. This capacity, the wide
voltage range and the simplicity of control, make the equipment
a remarkable group of apparatus.

CARBON BLACK PROM NATURAL GAS.
By G. St. J. Perrott and R. O. Neal.

An investigation of the carbon black industry has been under-
taken by the United States Bureau of Mines as a result of eco-
nomic issues brought up during the war. Considerable field work
has been done. Plants in Louisiana, Oklahoma, and West Vir-
ginia have been studied by Bureau engineers. The uses of carbon
black have been carefully investigated with the idea of de-
termining the properties of the product which users of carbon
black demand, and with an attempt at designating in which of
these uses carbon black is essential and in which a substitute ma-
terial might be employed. Microscopic and chemical examination
of a large number of blacks is being made and test methods studied
with a view to finding the reason for the very diflFerent behavior
exhibited by different blacks.

In the present process of manufacture, carbon b'ack is pro-
duced by burning natural gas with an insufficient supply of air
for complete combustion and collecting the liberated carbon on a
metal surface. Manufacturers of carbon black believe that this
process is the only one in practical operation which produces a
carbon Mack suitable for the ink trade and rubber industry. Over

Digitized by

Google

Aug., 1919] U. S. Bureau of Mines Notes. 275

10,000,000 pounds annually are used in ink manufacturing;
20,000,000 pounds annually are used in making automobile tires.

A Bureau of Mines bulletin on the Manufacture, Properties
and Uses of Carbon Black is in process of preparation.

MINOR NOTES.

Rare Metals. — The investigation of the metallurgy of Wulf-
enite, made at the Golden Station of the Bureau, has been com-
pleted and a report upon it will shortly be issued. The work upon
the production of zirconium from its ores is almost completed. A
bibliography of vanadium is also in course of preparation.

Fire Extinguisher Liquids. — An investigation of the various
types of commercial carbon tetrachloride fire extinguisher liquids,
made at the Pittsburgh station of the Bureau, has demonstrated
that when these liquids strike burning wood or red-hot iron the
carbon tetrachloride is partly decomposed and small amounts of
toxic gases are formed, so tiiat such extinguishers must be used
with caution in confined spaces.

Army Gas Masks in Fires. — Tests of the army type gas mask
for use in the irritating and choking smokes produced in fires
show that it oflFers complete protection against these, but allows
carbon monoxide to pass through. The cooperation of the fire
chiefs of the principal cities was secured in making the investiga-
tion. A report of this investigation will shortly be published.
These masks have also been tested in railway tunnels, and the re-
sults show that they should be of considerable use to engine men
when passing through tunnels.

Carbon Determination. — A laboratory method for the de-
termination of graphitic carbon in the presence of amorphous car-
bon has been standardized at the Pittsburgh station of the Bureau,
and is now* being checked on a large number of natural graphites
and amorphous carbon in the form of coal. The method gives
promise of being suitable for the direct quantitative determination
of graphitic carbon, which up to the present time has always been
an uncertain indirect determination. A laboratory method for the
determination of the various forms of sulphur in coal has been
tried on a number of typical samples of Eastern coal with very
satisfactory results.

Corrosion of Rifle Barrels. — An investigation of the after-

Digitized by

Google

276 U. S. Bureau of Mines Notes. IJFI-

corrosion of rifle barrels is in progress at the Pittsburgh station, in
cooperation with the Ordnance Bureau of the War Department.
The investigation is not yet completed, but the indications from the
work already done are that corrosion is due to solid products of
combustion that can only be removed by alkali or organic solvents.

Steam Boiler Tests, — The boiler tests which have been made
by the Bureau's engineers for the Emergency Fleet Corporation
at Erie, Pa,, with such excellent results to date, are to be con-
tinued. A series of tests has been started in which oil is used as
the fuel, and when the series is completed, a powdered coal test
will be made in cooperation with the Erie City Iron Works. A
series of tests on the use of coke for house heating purposes is
now in progress, comparative tests being made with anthracite.
An investigation has been started to determine the cause of the
incrustation of boiler tubes when using underfeed stokers.

Phosphorous in Iron Ores, — An investigation has been started
by the Minneapolis station to determine whether it is feasible to
leach out the phosphorous from medium and high phosphorous iron
ores. In connection with this an attempt will be made to develop
a standard method, for the determination of phosphorus in iron
ores that will be satisfactory to both buyers and seKiy-s.

Mining Conditions Abroad, — George S. Rice, Chief Mining
Engineer of the Bureau, has returned from an extended investiga-
tion of mining conditions in the Saar and Rhine Valley districts,
France, Belgium and Great Britain, and reports that the shortage
of fuel that prevailed during the war still continues and there is
probability of a still more serious deficiency unless the United
States increases its exports. This is due more to the general
unrest of labor and the increase in the cost of production (which
are 75 to 150 per cent, above those prevailing in 191 3) than to the
physical destruction of coal mines and their equipment. In
Great Britain the working hours underground have been reduced
from 8 hours to 7, effective July 16, and Sir Auckland Geddes has
made the statement that this will result in a production for 1920
of ,70,000,000 tons less than in 1913, and an increase in price to
the consumer. Meanwhile notice has been given in the House of
Commons that the price is to be raised $1.50 per ton on July 16.
This curtailing in output and increase in price in England, coupled
with a shortagJe of coal in western and central Europe, where the
various countries need 50,000,000 tons per year over their normal

Digitized by

Google

Aug.. 1919] U. S. Bureau of Mines Notes. 277

pre-war sources of supply, from countries other than Great
Britain. France alone needs 20,000,000 tons per year. The best
estimates are that Great Britain will be able to export somewhere
betAveen 7,000,000 and 25,000,000 tons in 1919 to all foreigjn
countries. There will therefore be a deficit of somewhere around
40,000,000 tons of fuel, for which the United States is the only
visible source of supply.

The mines destroyed by the Germans in the Nord-Pas de
Calais coal fields produced 20,000,000 tons of coal per year. It
will take two to five years to get these mines in working condition
and ten years to completely restore the production rate. The
taking over by France of Alsace and Lorraine and its occupation
of the Saar Valley will yield a certain amount of coal to make ujp
this deficiency, but as a large part of the output of these districts
is used locally the amount that can be cotmted on from these
sources is uncertain as yet, though it is reasonably certain that it
will nowhere near make up for the shortage in the Nord-Pas de
Calais district. The mines in Belgium were not injured, but there
is a shortage of skilled miners, and general labor conditions are
such that there is likely to be a deficiency of 40 per cent, of flie
output as compared with pre-war figures. Half of Spain's coal is
normally imported from England, eight-tenths of Holland's coal
is imported largely from Germany. Norway, Sweden and Den-
mark have all heavily drawn on Great Britain for coal. Germany's
principal coal-producing district is Westphalia. The only handi-
cap under which this district labors is the general unrest and the
weakened condition of the working population through insuffi-
cient food. The Ruhr field will probably be called on to deliver
a good deal of bituminous coal and coke to France in exchange
for the iron ore needed to keep the Ruhr blast furnaces operating.
The outlook for a demand for coal for export from the United
States is 'correspondingly bright.

Digitized by

Google

278 Current Topics. IJ- F- L

Surpliis Electric Power After the War. J. W. Beckm an.
(Amencan Electro-Chemical Socieiy, Transactions, 34th General
Meeting, 1918.) — It may be the case that we will have a surplus
of developed electric power after the worid has settled down to a
normal stride, this power having been developed in this emer-
gency for the supplying of munitions to us and our allies. It is,
therefore, important to face this fact now and consider how it
may be avoided or overcome.

It would be an economic waste of the very gravest magnitude
if this energy available on the bus-bars should be permitted to be
idle, a waste from two points of view: (i) from the point of in-
vested capital in the plant and equipment, and (2) perhaps a still
graver waste, from the point of merchandise that could be produced,
thus creating values and giving occupation to labor skilled and other-
wise helping to supply work to die millions of men who will return
to us after the war is won.

It is very apparent that many of the industries which are now
operating in connection with the war will have to let up some,
and equally certain it is that the power which they thus release
will not be absorbed readily by any other industry. This cer-
tainly will be the case if we do not as a nation and as individual
groups cooperate to extend our foreign markets, i.e., to tap new
market possibilities.

Two industries, both of them basic and both of them making
products essential to mankind, suggest themselves as being suit-
able life-savers to the electric developments after the war. One
is the iron and steel industry and the second is the fertilizer
industry. When I refer to the iron and steel industry-, I do not
refer cither to the electric shaft furnaces in Sweden nor to the
electric steel furnaces distributed all through the country.

I think the direct manufacture of steel from iron ore is not
out of the realm of the possible, and is one of the important
electro-metallurgical developments awaiting a successful solution.

We have already progressed some toward this goal. In the
electric shaft furnace low-carbon pig iron is now produced, known
as steel pig iron or pig steel. The next step wll be the finished
steel, suitable for the manufacture of the finished steel product
in the shape of ingots and castings. It may be a long step metal-
lurgically to take, but it is one that we should bend all our eflForts
upon to achieve. If we once accomplish it, we will find the iron
industry- gradually changing into an electrometallurgical one,
consuming enormous amounts of power and stimulating inci-
dentally other industries to activities of ver>- g^eat proportions.

The other industry* which would help to consume power is the
fertilizer industry. The ingredients necessar\- in a fertilizer
which would be most available for improved manufacture yrould
be nitrogen in some bound form, and phosphoric acid.

Digitized by

Google

THE FRANKLIN INSTITUTE.

LIBRARY NOTES.

PURCHASES.

AuLD, S. J. M. — Gas and Flame in Modern Warfare. 191 8.

Century of Science in America, With Special Reference to The American
Journal of Science, 18 18-1 91 9.

Henderson, G. G. — Catalysis in Industrial Chemistry. 1919.

Macfaklane, Alexander. — Lectures on Ten British Physicists of the Nine-
teenth Century. 1919.

Peele, Robert. — Compressed Air Plant. 1918.

Pernot, F. E. — Electrical Phenomena in Parallel Conductors. 191 8.

Race, Joseph. — Chlorination of Water. 191 8.

SiLBERSTEiN, L. — ^Vectorial Mechanics. 1913.

Sullivan, T. J. — Sulphuric Acid Handbook. 191 8.

Whiteshot, C a.— The Oil Well Driller. 1905.

GIFTS.

American Engineering Company, Catalogue of Steering Gear. Philadelphia,

Pennsylvania, 191 9. (From the Company.)
American Institute of Electrical Engineers, Transactions, Vol. xxxvii. Parts i

and 2. New York City; New York, 1918. (From Dr. R. B. Owens.)
Armour Institute of Technology, Bulletin of General Information, 1918. Chi-
cago, Illinois, 1918. (From the Institute.)
American Iron and Steel Institute, Annual Statistical Report for 191 7. New

York City, New York, 1919. (From the Institute.)
American Rolling Mill Company, Catalogue, " The Story of Armco Iron.'*

Middleton, Ohio, 1918. (From the Company.)
American Society of Heating and Ventilating Engineers, Year Book, 1919.

(From the Society.)
American Spiral Pipe Works, Catalogue of Pipe and Furnaces. Chicago,

Illinois, 1919. (From the Works.)
American Steam Gauge and Valve Manufacturing Company, Catalogue of the

American Thompson Improved Indicator. Boston, Massachusetts, 191 9.

(From the Company.)
Atchison, Topeka and Santa Fe Railway Company, Annual Report for the

Year 1918. New York City, New York, 1918. (From the Company.)
Baltimore Health Department, Annual Report, 191 7. Baltimore, Maryland,

1919. (From the Department.)
Bogue, Virgil, The Science of Fruit Growing. Albion, New York, 19 17.

(From the Author.)
Bryn Mawr College, Calendar of Undergraduate and Gra()uate Courses, 1919.

Bryn Mawr, Pennsylvania, 1919. (From the College.)

279

Digitized by

Google

28o Library Notes. [J* F- 1-

Buffalo Forge Company, Catalogue No. 410, Section 400. Buffalo, New York,

1918. (From the Company.)
Bureau of Foreign and Domestic Commerce, Statistical Abstract of Ae United

States, 19 18. Washington, District of Columbia, 1919. (From the Bureau.)
Cameron, A. S., Steam Pump Works, Bulletins. New York City, New York,

1918. (From the Works.)

Carpenter Steel (Company, Catalogue No. 8. Reading, Pennsylvania, 1919.

(From the Company.)
Chadbum Telegraph Company of America, Inc., Catalogue of Ship Telegraphs.

Troy, New York, 1919. (From the Company.)
Champion Engineering Company, Bulletin No. 106. Kenton, Ohio, 1919^

(From the Company.)
Chesapeake Iron Works, (Catalogue of Electric Traveling Cranes. Baltimore,

Maryland, 19191 (From the Company.)
Chicago. Burlington and Quincy Railroad Company, Sixty-fifth Annual Report

of the Board of Directors, 1918. Chicago, Illinois, 1919. (From the

Company.)
Colorado Bureau of Mines, Fifteenth Biennial Report for 1917-1918. Denver,

Colorado, 1919. (From the Bureau.)
Columbia University, Catalogue, 191&-1919. New York Gty, New York, 1919.

(From the University.)
Connecticut Dynamo Motor (Company, (Catalogue of Low Voltage Dynamos.

Irvington, New Jersey, 1919. (From the Company.)
Daigger, A., and Company, Catalogue of Laboratory Supplies and Chemicals

for Chemists and Bacteriologists. Chicago, Illinois, 1919. (From the

(Company.)
Davison, N. C, Gas Burner and Welding Company, Catalogue of Davison

Burners. Pittsburgh, Pennsylvania, 19191 (From the Company.)
Delaware Cx>llege, Annual Catalogue, 1918-1919. Newark, Delaware, 1919-

(From the College.)
Dixon, Joseph, Crucible Company, Graphite, Vol. xx, January to December,

inc., 1918. Jersey City, 1919. (From the Company.)
Doehler Die-Castings Company, Catalogue, Do-Di Finished Brass Castings.

Brooklyn, New York, 1919. (From the Company.)
Electric Furnace Company, Booklet 5-B. Alliance, Ohio, no date. (From the

Company.)
Electric Machinery Company, Bulletin No. 501. Minneapolis, Minnesota, no

date. (From the Company.)
Electric Welding Company. Clataloguc of Electric Welding by the Elwood

Process. Oeveland, Ohio, no date. (From the Company.)
Fellows GcsLT Shaper Company, Catalogue of Commercial (Sear Cutting.

Springfield, Vermont. 1919- (From the Company.)
Florida Stote (Geological Survey, Annual Report, 1019. Tallahassee, Florida,

1919. (From the Survey.)

General Fireproofing Company, Catalogue of GF Steel-Tile; Fireproofing

Handbook, 6th edition. Voungstown, Ohio, 1918. (From the Company.)

Georgia School of Technology-, Catalogue. 1918-1919, Announcements, 1919-

1920. Atlanta, Georgia, 1919- (From the School.)

Digitized by

Google

Aug., 1919] Library Notes. 281

GiflFord-Wood Company, Catalogue No. 31. Hudson, New York, 1919. (From

the Comi>any.)
Gold Car Heating and Lighting Company, Gold's Handy Reference. New

York City, New York, 1919. (From the Company.)
Goldschmidt Thermit Company, Catalogue of Thermit Carbonfree Metals.

New York City, New Yorl^ no date. (From the Company.)
Greaves-Klusman Tool Company, Catalogue, General Description of G-K

Betterments. Cincinnati, Ohio, no date. (From the Company.)
Greene, Tweed and Company, Catalogue of Steam Specialties. New York City,

New York, no date. (From the Company.)
Griscom-Russell Company, Bulletins 222-224, 230, 609, 1103. Philadelphia,

Pennsylvania, 1919. (From the Company.)
High Speed Hammer Company, " Let Us Shoulder Your Riveting Problems."

Rochester, New York, no date. (From the Company.)
Higler, Adam, Ltd., Catalogues of the Abbe Ref ractometers ; Higler Wave-
length Spectrometer; Nutting Photometer and the Refractive Index.

London, England, 1919. (From the Company.)
Hinde and Dauch Paper Company, Catalogue. Sandusky, Ohio, 1918. (From

the Company.)
Hires Turner Glass Company, Catalogue. Philadelphia, Pennsylvania. 1919.

(From the Company.)
Hood Manufacturing Company, Catalogue. Seattle, Washington, 191 9. (From

the Company.)
Hydro-Electric Power Commission of the Province of Ontario, Eleventh

Annual Report, 1918. Toronto, Canada, 1919. (From the Commission.)
India Department of Agriculture, Report on the Progress of Agriculture for

1917-1918. Calcutta, India, 1919. (From the Agricultural Adviser.)
IngersoU Milling Machine Company, Bulletin No. 38. Rockford, Illinois, 1919.

(From the Company.)
Jeffrey Manufacturing Company, Catalogue No. 175. Columbus, Ohio, 1919.

(From the Company.)
Keeler, E., Company, Catalogue, Cross Drum Water Tube Boilers. Williams-
port, Pennsylvania, 1919. (From the Company.)
K-G Welding and Cutting Company, Catalogue. New York City, New York,

1919. (From the Company.)
Lansing Company, Catalogue No. 17C. Lansing, Michigan, 191 9. (From the

Company.)
Leland Stanford Junior University, " A Contribution to the Knowledge of the

Cocdds of Southwestern United States"; "Derivation of the Flora of

Hawaii." Stanford University, California, 1919. (From the University.)
Liberty Manufacturing Company, Catalogue Z. Pittsburgh, Pennsylvania,

1919. (Srom the Company.)
Locomotive Dictionary and Cyclopedia, Fourth and Fifth Editions, 1916, 1919.

New York City, New York, 1916, 1919. (From Mr. Alfred W. Gibbs.)
Locomotive Stc^er Company, Catalogue No. 14-D. Pittsburgh, Pennsylvania,

1919. (From the Company.)
Locomotive Superheater Company, Bulletin T-2. New York City, New York,

1919. (From the Company.)

Vol. 188, No. 1124— -21

Digitized by

Google

282 Library Notes. IJ- F- I.

Lodge and Shipley Machine Tool Company, Catalogue of Lathes. Cincinnati,
Ohio, no date. (From the Company.)

Machinery Company of America, Catalogue No. 31. Big Rapids, Michigan,
no date. (From the Company.)

Maddem, John J., Scaffolding Company, Inc., Catalogue. Grf>shen, Indiana,
no date. (From the Company.)

Manchester Municipal 0>llege of Technology, Journal of Technology. Man-
chester, England, 1918. (From the College.)

Mehl Machine Tool and Die Company, New Prospectus of Tool Service,
Roselle, New Jersey, 1919. (From the Company.)

Michigan Public Domain Commission, Biennial Report, from July i, 1916^ to
June 30, 1918. Lansing, Michigan, 191 9. (From the C>ommission.)

Milwaukee Electric Crane and Manufacturing Company, Catalogue. Mil-
waukee, Wisconsin, no date. (From the Company.)

Minneapolis, St. Paul and Sault Ste. Marie Railway Company, Thirtieth
Annual Report, 1918. Minneapolis, Minnesota, 1919. (From the Com-
pany.)

Molby Boiler Company, Inc., Catalogue of Molby Magazine Feed Down Draft
. Boilers. New York City, New York, 191 7. (From the Company.)

Morgan Engineering Company, Bulletin No. 15. Alliance, Ohio, 1919. (From
the Company.)

Morris, Herbert, Crane and Hoist Company, Ltd., Book No. 66. Niagara
Falls, Canada, 191 9. (From the Company.)

Murray Iron Works Company, Catalogue No. 85. Burlington, Iowa, 1919.
(From the 0>mpany.)

New Jersey Foundry and Machine Company, Catalogue No. 99. New York
City, New York, 191 8. (From the Company.)

New South Wales Royal Society, Journal and Proceedings for 1917.
Sydney, Australia, 1918. (From the Society.)

New York Conservation Commission, Annual Report, 1916. Albany, New
York, 1918. (From the Commission.)

New York Public Service Commission, Annual Report, 191 7. Albany, New
York, 1918. (From the Commission.)

New Zealand Government Statistician, Statistics of the Domain, 1917. Wel-
lington, New Zealand, 1918. (From the Government)

North Eastern Construction Company, Catalogue of Giant Concrete Piles.
New York City, New York, no date. (From the (Company.)

Norwalk Iron Works Company, (Catalogue of Air and Gas Compressors.
South Norwalk, Connecticut, 1919. (From the Company.)

Novo Engine Company, Bulletin No. 11. Lansing; Michigan, no date. (From
the Company.)

Ohio^ Engineering Society, Report of the Fortieth Annual Meeting. Columbas,
Ohio, 1 919. (From the Society.)

Ohien, James, & Sons, Saw Manufacturing Company, Catalogue No. 74.
Columbus, Ohio, 1919. (From the Company.)

Parks-Cramer Company, Catalogue, Fluid Heat Transmission. Boston, Massa-
chusetts, 1919. (From the Company.)

Digitized by

Google

Aug., 1919.] Library Notes. 283

Pittsburs^h, Cincinnati, Chicago and St Louis Railroad Company, Annual
Report for the Year Ending December, 1918. Pittsburgh, Pennsylvania,
1919. (From the Company.)

Price Electric Company, Catalogue, The Price Indicating and Recording
Pyrometers. Qeveland, Ohio, no date. (From the Company.)

Redwood Manufacturers' Company, Catalogue. San Francisco, California,
191 i>. (From the Company.)

Reed-Prentice Company, Bulletins of various types of lathes. Worcester,
Massachusetts, no date. (From the Company.)

Reynolds Machine Company, Catalogue F. Massillon, Ohio, 1919. (From
the Company.)

Rio de Janeiro Museu Nacional, Archivos Vol. xxi. Rio de Janeiro, 1918.
(From the Museum.)

Shepard Lewis Company, Catalogue of the Jacklift Master Truck. Boston,
Massachusetts, 1918. (From the Company.)

Simonds Manufacturing Company, Catalogue of Saw Steel Products. Fitch-
burg, Massachusetts, no date. (From the Company.)

Slocomb, J. T., Company, Catalogue and Measuring Book No. 16. Providence,
Rhode Island, no date. (From the Company.)

Somerville Street Commissioner, Annual Report, J918. Somerville, Massa-
chusetts, 1919. (From the Commissioner.)

South Bend Lathe Works, (Catalogue of Machine Shop Equipment for Voca-
tional and Industrial Schools. South Bend, Indiana, 1918. (From the
Works.)

Standard Spiral Pipe Works, Catalogue No. 7. Chicago, Illinois, no date.
(From the Works.)

Steam Motors Company, Bulletin No. 5. Springfield, Massachusetts, 1919.
(From the Company.)

Taunton, Massachusetts, Water Commissioners, Forty-third Annual Report,

1918. Taunton, 1919. (From the Commissioners.)

Terry Steam Turbine Company, Catalogue. Hartford, Connecticut, no date.

(From the Company.)
Tide Water Oil Company, Catalogue of Fuel Oil. New York City, New York,

1919. (From the Company.)

Transmission Ball Bearing Company, Inc., Catalogue of Chapman Type Ball
Bearings for Transmission. Buffalo, New York, no date. (From the
Company.)

Truscon Steel Company, Catalogue of Steel Windows. Youngstown, Ohio,
1918. (From the Company.)

Trussed Concrete Steel Company, Catalogue of Canadian Steel Casements.
Walkerville, Ontario, Canada, no date. (From the Company.)

Unit Railway Car Company, Catalogue, The Unit Car. Boston, Massachu-
setts, 1919. (From the Company.)

U. S. Naval Observatory, The American Ephemeris and Nautical Almanac
for the Year 1921. Washington, District of Columbia, 1918. (From the
Observatory.)

University of Minnesota, Bulletin No. 16. Minneapolis, Minnesota, 1919.
(From the University.)

Digitized by

Google

284 Correspondence. [J. F. L

University of Nevada, Catalogue, 191^1919^ Including Announcements for

1919-1920. Reno, Nevada, 1919. (From the University.)
University of Pennsylvania, Catalogue, 191^1919; Announcements, 1919-

1920. Philadelphia, Pennsylvania, 1919. (From the University.)
University of Texas, Catalogue of the University and of The State Schod of

Mines and Metallurgy, 1918-1919. Austin, Texas, 1919. (From the

University.)
University of Vermont, Catalogue, 191^1919. Burlington, VcrmtHit, 1919.

(From the University.)
Warner and Swasey Company, Catalogue of Turret Lathe Tools. Qcveland,

Ohio, 1918. (From the Company.)
Wheeler, C. H., Manufacturing Company, Catalogue of Condensers and

Auxiliaries. Philadelphia, Pennsylvania, 1919. (From the Company.)
Wilson Welder and Metals Company, Inc., Repair of the German Ships. New

York Gty, New York, 1918. (From the Company.)
Wilton Tool and Manufacturing Company, Catalogue, Standardization by

Wilton. Boston, Massachusetts, 1919. (From the ConH)any.)
Wright-Austin Company, Catalogue of Steam Specialties. Detroit, Michigan,

191 9. (From the Company.)
Yale and Towne Manufacturing Company, Semi-Centennial Souvenir, 1868-
1918. (From the Company.)

CORRESPONDENCE.

Bureau of Construction and Repair, Navy Department.
Mr, R. B. Owens, Washington, D. C, July 2, 1919.

Secretary, Franklin Institute,
Philadelphia, Pa,
My Dear Sir :

During my absence in Europe, there was received at my office the certifi-
cate of my election to Honorary Membership in The Franklin Institute, dated
April 16, 191 9. It has recently come to my attention that this certificate was
not acknowledged, and I feel much mortification at the apparent neglect.

I beg to assure you and the members of the Institute of my deep aw>re-
ciation of the honor conferred upon me.

Very sincerely,

(Signed) D. W. Tayl<»,
Rear Admiral,
Chief Constructor of the Navy,

John J. Carty,
195 Broadway,
New York.
Doctor R, B, Owens, Secretary, July 15, I9I9-

The Franklin Institute, Philadelphia, Pa.
Dear Doctor Owens :

I have just been discharged from the Army and am at work on affairs
which have accumulated and which require my attention.

Digitized by

Google

Aug.,1919.] Publications Received. 285

I have had a most gratifying surprise in receiving the diploma showing
that I have been elected to be an Honorary Member of The Franklin Institute.
This coming upon the other honors and courtesies which I have received at
the hands of your society places me under so many obligations that I can
never sufficiently express my feelings of high appreciation of The Franklin
Institute and of its distinguished officers and members.

I assure you that I shall endeavor always to show that I am sensible of this
great honor whicJi has been conferred upon me.

Very sincerely yours,
JJC-AM (Signed) John J. Carty.

BOOK NOTICE.

The Realities of Modern Science. An Introduction for the General Reader.

By John Mills, Research Laboratories, Western Electric Co., Inc. 321

pages, contents, index, 44 illustrations, i2mo. New York, The Macmillan

Company, 1919. Price, $2.50 net.

Several useful books for popularizing science have appeared of late years
from American authors. Some of these have been condensed histories, others
accounts of scientific procedures, principally chemical, expressed in non-
technical language. They have been of much service in bringing to notice
the value and the methods of modern science. The present work is more
strictly scientific, but is well adapted to those who want information on some
of the data of physics and chemistry, especially the border-land of these two
sciences, physical chemistry, which has progressed at such a rapid rate in the
last quarter-century.

The work begins with an exposition of the author's views as to the methods
of the beginnings of knowledge, which, as might be expected, is the least
satisfactory part of the book, as the information at hand on this point is very
scanty, and in a book which deals so largely with exact scientific data, this
presentation of the speculations — ^telescopic deductions from microscopic
premises, as they have been termed — is a discord in the music. The author
states among other things that monkeys probably use tools only in imitation
of human beings, and that having no thumbs they cannot pick up articles. It
is, however, stated on good authority that even in the wild state they throw
sticks and stones at intruders, and they certainly have the ability to pick up
even small objects. These questions are, however, of minor importance and
do not in any way affect the merit of the work, which gives valuable informa-
tion on some of the latest and most important phases of physical chemistry.
Large space is devoted to the subjects of electrons, electrolytic dissociation
and the various problems of molecular physics. The book will be a valuable
contribution to the literature of the subject

Henry Leffmann.

PUBLICATIONS RECEIVED.

The Realities of Modem Science: An Introduction for the General
Reader, by John Mills. 327 pages, illustrations, i2mo. New York, The
Macmillan Company, 1919. Price, $2.50.

Digitized by

Google _

286 Publications Received. [JF i

Induction Coils in Theory and Practice: By Prof. F. E. Austin, E.E. 64
pages, illustrations, 8vo. Hanover, N. H. Author, 1919. Price, $1.

Illinois Department\ of Registration and Education, Division of the State
Water Survey: Bulletin No. 15. Chemical and Biological Survey of the
Waters of Illinois. Report for year ending December 31, .1917. 133 pages,
map, 8vo. Urbana, State printers, no date.

University of Missouri, School of Mines and Metallurgy: Forty-eighth
Annual Catalogue. 163 pages, 8vo. Rolla, University, 1919.

United States Geological Survey: Advance Statement of the Produc-
tion of Copper in the United States in 1918, by B. S. Butler. 6 pages, 8vo.
Washington, Government Printing Office, 1919.

U. S. Department of Labor, Working Conditions Service: How to Give
Illustrated Lectures on Accident Prevention to Workmen. 13 pages, 8vo.
Washington, Government Printing Office, 1919.

[/. 5*. Bureau of Mines: Bulletin 151, Recovery of Gasoline from
Natural Gas by Compression and Refrigeration, by W. P. Dykema. 123 pages,
illustrations, plates, 8vo. Bulletin 165, Bibliography of Petroleum and Allied
Substances in 1916, by E. H. Burroughs. 159 pages, 8vo. Bulletin 176, Recent
Developments in the Absorption Process for Recovering Gasoline from
Natural Gas, by W. P. Dykema. 90 pages, illustrations, plates, 8vo. Bulletin
179^ Abstracts of Current Decisions on Mines and Mining, reported from
September to December, 1918, by J. W. Thompson. 166 pages, 8vo. Monthly
Statement of Coal-mine Fatalities in the United States, March and April, 1919,
compiled by Albert H. Fay, 2 pamphlets, 8vo. Technical paper 222, Method
of Administering Leases on Iron-ore Deposits Belonging to the State of
Minnesota, by J. R. Finlay. 40 pages, illustrations, 8vo. Technical paper 223,
Cost Keeping for Small Metal Mines, by J. C. Pickering. 46 pages, diagsams,
8vo. Technical paper 224, Metal Mine Accidents in the United States During
the Calendar Year 1917, compiled by Albert H. Fay. 80 pages, 8vo. Wash-
ington, Government Printing Office, 1918-1919.

The Producticm of Liberty Motor Parts at the Ford Plant.
W. F. Verner. (The American Society of Mechanical Engineers,
Spring Meeting, June, 1919.) — The contract made with the United
States Government cajled for 5000 motors and these were to be pro-
duced at the rate of 50 per day of eight hours. To do this, impor-
tant developments in the methods of manufacture were brought
about by the Production Department of the Ford Motor Company.

One of these was the method of producing cylinders frpm tubing.
Six operations were necessary and the author describes them in
detail. The methods employed to produce connecting-rod crank-
shaft bearings likewise resulted in a great saving of time. Twenty-
one operations were found necessary for this work and a complete
description of each is given. The method of installing bearings in
the upper and lower halves of the Liberty motor crankcase, is also
described.

Digitized by

Google

CURRENT TOPICS.

The Alcohol Problem. — ^This note is not to discuss the ques-
tion of the proportion of alcohol constituting a beverage as " in-
toxicating " nor the sociologic phases, but to point out that the
practice of civilized countries of imposing heavy taxes on ethyl
hydroxide is one of the most serious interferences with indus-
trial development. Standing next to water as a general solvent,
and having solvent powers on a large number of important sub-
stances not soluble in water, alcohol now finds extended use in
the arts. Although governments have endeavored to release in-
dustrial alcohol from the tax burden, yet the only method so far
generally adopted — that of incorporating with it ingredients that
render it unfit for internal use — is by no means satisfactory.
Apart from the uses of alcohol as a solvent, its adaptability as a
fuel both directly and in the internal combustion engine opens up
a great opportunity. It is of lower energy, weight for weight,
than gasoline, but the fire-risk is so much lower and the odor
unobjectionable.

The United States Government should institute a compre-
hensive research with a view of discovering cheap methods of
producing alcohol and of devising means by which it can be
sold freely for use in everything but beverages. The problems
are complicated but they are not unsolvable. One question
always presents itself to the law-maker, namely, the loss of
revenue that will follow the removal of the tax. The restrictions
that are imposed on the manufacture and sale of alcohol are due
to the wide-spread opinion that taxes should be raised largely on
luxuries, and alcohol has always been regarded as of this type,
but apart from the changed conditions that will follow nation-
wide prohibition, it surely is possible that taxes can be levied
so as to be incident dn the luxury and not on useful applications.
The subject is too extensive to be discussed fully here, but it is
well worth careful consideration by those interested in the ad-
vancement of the industries. H. L.

Ash Removal by Suction. (Scientific American, vol. cxx.
No. 25, p. 661, June 21, 1919.) — ^What is virtually a large-sized
vacuum cleaner has been delivered to a concern in New York
City that specializes in cleaning ash bins of public buildings and
large residences, and while the apparatus is experimental be-
cause it is now being tested out, the designers feel sure that it
will prove to be not only practical and efficient, but will meet
with the approval of the general public by minimizing the dis-
comforts and dirt now met with in ash removal by the usual
means of dumping the filled galvanized iron containers into open
cart bodies.

287

Digitized by

Google

288 Current Topics. I J- F- 1-

The equipment is mounted on a five-ton chassis and is a large
box compartment, resembling the conventional van, the doors
and gates of which can be closed tightly. On the chassis is
mounted a blower that is driven by the engine, and this is so
adapted that ashes are drawn into the compartment from the
ash pit, no matter what the angle, through a telescoping metal
tube. The truck is driven to the curb at the nearest point to the
ash pit, and the tube is extended into it. The ashes must be
shoveled to the lower end of the tube and the suction carries
them into the compartment on the truck.

The labor is limited to shoveling into the ash pit, or at least
handling so the ashes can be drawn out by the blower, and there
is no dust blown about outside. The time of loading the truck
is much more rapid than would be possible were the work done
manually, and this is of material importance when the time of
trucks is considered as representing a substantial value. The
prevention of dust will be approved by all sanitary departments
of municipalities. The work of the apparatus is so satisfactory
that adoption will soon be general, both for municipalities and
for contractors.

Insect Helps Control Other Insects. (U. S, Department of
Agriculture, Bulletin No. 766.) — An European parasitic fly that may
become of far-reaching importance in the control of the gipsy
moth and brown-tail moth and certain other serious pests of
similar character is being multiplied from importations of this
new insect enemy. A report of the work with the parasite —
known as Compsilura concinnata — has just been made by ento-
mologists of the United States Department of Agriculture.

This report shows that this parasite has reduced the damage
done by the gipsy moth and the brown-tail moth in the New
England States, where they were so abundant and destructive
that they ate the leaves off enormous areas of forest and shade
trees every year. It has been found that Compsilt^ra also aids in
the control of other insect pests.

The white-marked tussock moth, a serious pest in the New
England States a few years ago, has practically disappeared
since Compsilura has become established. The cabbage worm, still
a serious pest, has been lessened in some sections. Celery worms
are not as common as formerly, and the fall webworm is scarcely
noticed in the Northeastern States now.

The entomologists do not claim that this parasite is the sole
cause of this reduction, but it has proved an important natural
enemy to all of them. It is thought that Compsilura may become
one of the most important economic parasites in this country.

♦

PRESS OF
J. B. LIPPINCOTT COMPANY
PIIILADBLPHIA

Digitized by

Google

Journal of The Franklin iNSTmrrE,
OFFICERS FOR Z919

wasiDBiiT Walton Clark

▼ICB-PRSSIDBHT8 Hbnrt Howson

COLBMAN SbLLBRS, Jr.
8BCRBTART R. B. OwENS

TRBASURBR CtRUS BoRGNBR

BOARD OF M AHA6BR8

Gellbrt Allbman Gborgb R. Hbndbrson

Francis T. Chambbrs Charlbs A. Hbxambr

G. H. Clambr (jBOrgb A. Hoadlbt

Theobald P. Clark Harry P. Kbllbr

Charles Day Robert W. Lesley

Kern Dodge Marshall S. Morgan

W. C. L. Eglin Edw. V. McCaffrey

Walton Porstall Lawrence T. Paul

Benjamin Franklin Jambs S. Rogers

Alfred W. Gibbs Geo. D. Rosbngarten

Alfred C. Harrison B. H. Sanborn

Nathan Hayward William C. Wetherill

board of trustees

Joseph C. Praley, Preddent
William L. Austin John Gribbbl

Charlbs E. Brinlby Alfred C. Harrison

Walton Clark Frederick Rosengartbn

The Board of Trastees was formed in accordance with the following
By-Laws passed in the year 1887:

ah Real and Personal Estate of the Institute which may hereafter be aoqutred
by voluntary subscription or devise, bequest, donation, or in any way other than
through its own earnings or by investment of its own funds, saving where the
donors shall expressly provide to the contrary, shall be taken as acquired upon
the condition that the same shall be vested in a Board of Trustees, who shall be
appointed in the manner hereinafter indicated. Unless the title to such property
shall be directly vested in said Board of Trustees by the donors, the Institute,
by deed attested by the President and Secretary, which they are hereby author-
ised to execute and deliver, shall forthwith convev the same to said Trustees,
who shall hold it in trust for the purposes specifically designated by the donors;
or. if there shall be no specific designation, for the benefit of the Institute in the
way and manner hereinafter provided, so that the same shall not. in any event
be liable for the debts of the Institute.

This method of separating the body holding the principal of the various
funds from the Board of Managers, the spending body, is an original idea
of The Franklin Institute and it is hoped it will appeal to friends who may
desire to create funds to further the objects ot the Institute, and the
▼arious branches of V^ience in which they may be interested.

Digitized by

Google

Journal of Th« Franklin In^tituts.

MEMBERSHIP.
Tenns and PrlTllagM.

THB MBMBBRSHIP OF TSE INSTITUTB is divided into the foUowtag
elasaes, vis.: Resident Members, Stackhcidets, Life Members, Permaneni Members,
Nim-resident and Associate Members. •

Any one interested in the purposes and objects of The Institute and ex-
pressing a willingness to further the same may become a member when proposed
by a member in good standing and elected by the Board of Manai^ers.

TERMS.— Resident members pay Fifteen Dollars each year. The payment
of Two Hundred Dollars in any one year secures Life Membership, with exemp-
tion from annual dues.

STOCK. — Second-class stockholders pay an annual tax of Twelve Dollan
per share, and the holder of one share is entitled by such payment to the
privileges of membership.

PRIVILEGBS. — Bach contributing member (including non-residents) and
adult holder of second-class stock is entitled to participate in the meetings of
The Institute, to use the Library and Reading Room, to vote at the Annual
Election for ofiBcers, to receive tickets to the lectures for himself and friend, to
attend the Section meetings and to receive one copy of the Journal free of
charge, except associate members, who may not take part in elections.

PERMANENT MEMBERS. — The Board of Managers may grant to any
one who shall in any one year contribute to The Institute the sum of One
Thousand Dollars a permanent membership, transferable by will or otherwise.

ASSOCIATE MEMBERS.— Associate members are accorded all the privi-
leges of The Institute, except the right to vote or hold office, upon the payment
of annnal dues of Five Dollars. This class of membership is limited to persons
between the ages of seventeen and twenty*five years. Upon reaching the age
limit they become eligible to the other classes of membership,

RESIGNATIONS must be made in writing, and dues must be paid to ^he daU
of resignation.

, For. further information and membership application blanks ad4resi the
Secretary of The Institute. , . • , * • !

Digitized by

Google

AWARDS BT THE INSTITUTE

The following awards are made by The Franklin Institute :

The Franklin Medal (Gold Medal and Diploma).— This medal it
awarded annually from the Franklin Medal Fund, founded January i, 1914,
by Samuel InsuU, Esq., to those workers in physical science or technology,
without regard to country, whose efforts, in the opinion of the Institute,
acting through its Committee on Science and the Arts, have done most to
advance a knowledge of physical science or its applications.

The Elliott Cretton Medal (Gold Medal and Diploma).— This medal
it awarded for discovery or original research, adding to tiie sum of human
knowledge, irrespective of commercial value; leading and practical utiliza-
tions of discovery; and invention, methods or products embodying sub-
stantial elements of leadership in their respective classes, or unusual skill
or perfection in workmanship.

The Howard N. Potts Medal ((^Id Medal and Diploma).— This medal
is awarded for distinguished work in science or the arts; important
development of previous basic discoveries; inventions or products of
superior excellence or utilizing important principles; and for papers of
especial merit that have been presented to the Institute and published in its
Journal.

The Edward Longttreth Medal of Merit (Silver Medal and Diploma).—
This medal, with a money premium when the accumulated interest of
the fund permits, is awarded for meritorious work in science or the
arts; including papers relating to such subjects originally read before
the Institute, and papers presented to the Institute and published in its
Journal. In the event of an accumulation of the fund for medals beyond the
sum of one hundred dollars, it is competent for the Committee on Science
and the Arts to offer from such surplus a money premium for some special
work on any mechanical or scientific subject that is considered of sufficient
importance, or for meritorious papers presented to the Institute and pub-
lished in its Journal.

The Certificate of Merit— A Certificate of Merit is awarded to persons
adjudged worthy thereof for their inventions, discoveries or productions.

The Boyden PremiunL— Uriah A. Boyden, Esq., of Boston^ Mass., 'has
deposited with Thr Franklin Institute the sum of one thousand dollars, to be
awarded as premium to "any resident of North America who shall determine by
experiment whether all rays of light, and other physical rays, are or are not
transmitted with the same velocity."

For turtkw infomuitioii relating to thoM awards apply to tho Socrotaiy of tha Imtitnto.

Digitized by

Google —

Journal of The Franklin Institute.

THE FRANKLIN INSTITUTE AWARDS

Notice is hereby giyen that THE FRANKLIN INSTITUTE,

tlirough its Committee on Science and the Arts,

proposes to award

THE HOWARD N. POTTS GOLD MEDAL

CLARENCE P. LANDRETH

PHILADELPHIA. PA.
For his

ELECTROLYTIC SEWAGE PROCESS

R. B. OWENS,

Secretary.

HALL OF THE INSTITUTE
June 1, 1919.

Digitized by

Google

Journal of The Franklin Institute.

THE FRANKLIN INSTITUTE AWARDS

Notice is hereby giyen that THE FRAnKLIN INSTITUTE,

through its Committee on Science and the Arts,

proposes to award

THE HOWARD N. POTTS GOLD MEDAL

Jomtly to

REYNOLD JANNEY

NEW YORK. N. T.
AND

HARVEY D. WILLIAMS

WALLINGFORD. CONN.

For the Invention of the

WATERBURY HYDRAULIC SPEED GEAR

R. B. OWENS,

Secretary.

HALL OF THE INSTITUTE
June 1, 1919.

Digitized by

Google

JOCRKAL OF THE FrAXKLIX IxSTTTUTE — AdVYXTISEMESTS,

FIDELITY TRUST COMPANY

NiiL 325-331 CHESTNUT ST. t4m, 43-53 SOUTH FOURTH ST.

BROAD ST. OFFICE: NL E. COR. BROAD AND CHESTNUT STSl

$5,000,000
$16,000,000

HAMLIN AMORKISON

ANALYTICAL CHEMISTS

FORREST BUILDING
PHLADELPHA

BANCROFT & BROTHER

lilj— gBMIBSI

o^ o„ T ^^ ^ STEAM FITTING

RieUe Bros. Totec Macfane Co. PLrUMBING

m* «. Mk St, Pii i MT . r^ j«,|„ Borden and Bro.

lh« LaiMt lapravtd Unud Stato Scaadud
Tod^ MackiMty awi AppiManstrfaU nrictics

The MOORE & WHTTECO.

PHILADELPHIA. PA..U.S.A.

Paper-making Machinery
Builders of j Friction Clutch Pulleys
Variable Speed Changes

r*ar routwr ia ■•ntlonlng th* Joara«l will b* apprMlatad

riv

Digitized by

Google

Journal of The Frankun Institute — Advertisements.

"NICE"

PAINTS, VARNISHES, FILLERS

For ETery Purpose

EUGENE E. NICE, Mfr.

272-274 Soatb Socond Street Philedelpllk

QUALITY
DELIVERY

AND A

FAIR PRICE

The Constituents
of Good Printing

All to be had for the atldng

Bradley Printing Co.

Printers — EngraTers
Blank B«ok Makers

1214 Santom Street, PhiU.

SAMUEL P. SADTLER &SON

Analyses and repoits made in all branches of
Indostrlal and applied chemistry. Expert assist-
ance in the development of chemical processet
and patents, and preparation of testimony is
cfiemical patent suits. Raw materials and waste
prodncu of mannfacturinff processes specially
studied and reported upon.

Office and Laboralory-210 S. 13th St^ PhiU

Eiperimeotal Shop^— Cheitout Hill, Fa.

PATENTS

Procured lor In-
ventions and de-
L « . signs. Trade

marks Reiristered, Patent Causes. £zaminatlons
Searches, etc. Call or send for fiook of Instructions:

WIEDERSHEIM ft FAIRBANKS
John A. Wiedersheim DeLona Building

Wm. Caner Wiederselm laaa Chestnut St.

H. Hay ward Fairbanks Philadelphia

Drawing Materials
Surveying Instrumeoti

Bine, Brown and Direct
Black-Line Print Papers

WEBER & CO.

1125 CheitDiiiStnet

>ar Generalon

LVEL GEARS
Boretically Correct

ties for Cutting Wonn, Splial.
Uand Elliptical Gear Wftedi

THEIIILGIAM
MACUNE WOBKS

1229 Spiiai Gaidea St.
Phils.. Pb.

Philadelphia Book Co.
ENGINEERING AND
TECHNICAL BOOKS

17 SOUTH NINTH STREET

Bel Telephone Wahot 1002

Your courtesy In mentioning the Journal will be appreciated

Digitized by

Google

Journal op The Franklin Institute — ^Advertisements.

CONSERVE ELECTRICITY

Using the wrong type of lamp is just as extravagant, pro-
portionately, as buying two or three times the amount of coal
you need and throwing out the surplus with the ashes.

If you will see to it that there are

MAZDA LAMPS

in every lighting socket in your home or place of business
you can be sure that you are getting the full worth of your
money, not only in the greater amoimt of Ught for the current
consumed, but in the greatly improved quality of illumination.
Mazda lamps give three times as much Ught for the same
money as the old carbon or Gem lamps. Electric illumination
by Mazda lamps, therefore, is the most economical lighting
method, whether for residence, store or factory.

THE PHILADELPHIA ELECTRIC COMPANY

£if^ cars

C€M.OMWtMfit

fOMMERC/AL

riHtt-AOELPH/A.

CYRUS BORGNER COMPANY, ^^^o^ssaa^io

*^V^ ^^ t

Your courtesy lo meotioolng the Journal will b« appreciated
rvi

Digitized by

Google

Journal of the Franklin Institute — Advertisements.

Tour courtesy in mentioniDK the Journal will be appreciated

Digitized by

Google

C8TASU9HKO 1869.

ilERICiN STiNDJJtS

FILES^RflSPS.

LOCOMOTIVES

STEAM LOCOMOTIVES

for All Classes of Service.

INTERNAL COMBUSTION LOCOMOTIVES

for light Indtistrial, Contractors, and
Switching Service.

SPARE LOCOMOTIVE PARTS

made to Gauges and T^nplets, thus
insuring Interchangeahility.

THE BALDWIN LOCOMOTIVE WORKS

PHILADELPHIA, PENNA.

Black Diamond File Works

Twelve Meddt

Awarded
■t IntemalioiuJ

EULDOSlbOOS

Special Prize

Gold Medal

ftt Alkiili,Gt.
1695

Q. & H. BARNETT COMPANY Philadelphia, Pa.

OwBcJ Mitf OfMratod by NICHOLSON PILE CO.

See o« ezha>it b the Bourse, Fifth near Market Street, Pfakaelphia

Copy of Cmtalofue will be sent free to any intetested file-neer apoo appUcatfcm.

Digitized by

Google

Digitized by

Google —

Digitized by

Google

Digitized by

Google

Digitized by

Google

Internet Archive Audio

Featured

Top

Images

Featured

Top

Software

Featured

Top

Books

Featured

Top

Video

Featured

Top

Mobile Apps

Browser Extensions

Archive-It Subscription

Save Page Now

Full text of "Journal of the Franklin Institute [electronic serial]"

See other formats