BENJAMIN FRANKLIN 
A s  a Scientist 

By ROBERT A. MILLIKAN 

ENJAMIN Franklin i s  perhaps the only American i n  
tliat relatively small provp of men of any time or 
country who, without having been either the head bf 

a s t  o r  a military hero. h a t e  k c t  gained so coil. 
ieuoiis a place in history thal their name5 and saving5 
e known the world w p r .  4Ithough he l n e d  200 
a r s  ago in %hat \ \ a s  then a remote cornei of 

ie earth. f a r  f r o m  a m  of the ceiitcra < i f  n o r l d  inflii- 
re, vet his name and traits arr still \\idel\ k n ~ i u n .  
a I quote a paragraph f r o m  a ~ h o i - t  biographj or 
ichekon u h i c h  I puhlislied in the Scientific Monthlv 

or January. 1939: 

I t  will probalill he p i e i a l l !  agreed thal the tlnee 
i c a n  physicists whose work has been most epoch- 
i i g a n d  whose name-' a r e  most ceitiiin to he i r e -  

ently heard wherever and whenever i n  future year" 
ie story of physic? is told are Benjamin Franklin. 
osiali Willard Gibhs, and Albert A Mi~lielsoii. Ami 

t i e  three have almost no charartrristic-< in coin- 
Franklin lives as a phxsicist I ~ c J I I - ~ .  dilettante 

¡; lie i s  sometimes called. mere qualitatixe inter- 
e er thouzh h e  actuallv was. vet it was he who with 



Title p a g e  of t h e  same b o o k - o n e  of t h e  first vol- 
umes t o  b e  illustrated by t h e  copperplate engraving 

process. 

into the fundamental nature of electrical phenomena, 
not merely than any one had acquired up to his time, 
hut even than any of his successors acquired f o r  the 
next 1 5 0  years, when, about 1900, the scientific world re- 
turned essentially to Franklin's views. 

T o  justify this statement and to b r i u g t o  light the 
extraordinary quality both of Franklin's physical insight 
and of his power of induction I shall make most of the 
remainder {if this article consist of a few direct quota- 
tions from Peter Collinsnn letters whir?) the editor in- 
forms u s  were being printed "without waiting f o r  the 
ingenious author's permission to do so.'' 

The first letter. dated March 28. 1747. leads: 
"To Peter Collinson, Esq.; F. R. S. London 

Philadelphia, March 28, 1747 

ihaenomena that vie look MDOB to be new. I shall tliere- 
fore communicate them to you i n  my next.thoiighpossibly 
they may not lie new to you. a s  among t h e  numbers daily 
employed in those experiments on your side t h e  water, 'tis 
probable some one or other has h i t  on the saiHe observations. 
For my own part, I never was before engaged i n  any study 
that so totally engrossed m y  attention and my time as this 
h a s  lately done; for what with making experiments when I 
1 be alone, and repeating them to my Friends and Ac- 
t who. from t h e  novelty of t h e  thing, come COW 
tinually in crowds to see them. T have. (hiring sonic months 
past. hatf little leisure for any thing else. 

"I am, etc. 
- -. Â ¥ B  Franklh " 

.A straight three-foot s-lass tube as big As your v i i s t  

Now as t o  some of the experiments themselves. T h e  
very first one of them, done within a few months of the 
time h e  first heard of electricity, contains the key to 
his invention of the lightning rod. Note f r o m  the fol- 
lowing how skillfully and strikingly h e  arranges his 
electrostatic experiments by making the length of the 
suspension of the cork ball very long. After 200 years 
of the development of electrostatics these experiments 
cannot he made more tellingly today than by setting 
them up and performing them exactly a s  Franklin 
directed nearly 2 0 0  years ago. H e  writes: 

"The first is the wonderful effect of pointed bodies, 
both in drawing off and throwing off the ~ l c c t r i c a l  fire. 
For example, 

' P l a c e  an iron shot of thiee or four inches diameter 
an the mouth of a clean dry glass bottle. By a fine silken 
thread from the ceiling, n g h t  over t h e  mouth of the bottle, 
suspend a small cork-bail about the bigneas of a marble; 
the thread of such a length, a- that the cork-ball may rest 
against t h e  side of the -hot. Electrify tlic <hot, and the 
ball will be repdlpd to the distance of four or five i n < h ~ s .  
more or le-s. according to the quantity of Electricity- 
When in this state, if you present to t h e  shut t h e  point of a 
long. slender, nhurp bodkin, at i i x  or eight inches distairv. 
the repellency is instantly destroyed, and the cork flies to 
t h e  shot. A blunt body must be brought within an inch, and 
draw a '.park, to produce the same effect. To p m w  thnt 
the electrical fire is drawn, off by t h e  point, if you t a k e  t h e  
hlade of the bodkin out of t h e  wooden handle. and fix it i n  
a "tick of sealingwax, and then present i t  at the distancv 
aforesaid, or if 5011 bring it very near, no -itch effect fol- 
low.: but sliding one finger along t h e  wax till you touch 
t h e  blade, and the ball flies to the shot immediately." 

Here i s  where h e  learned that his lightning rod had 
to have a good ground i n  order to work at all. He ron- 
tinues: 

"To i-how that points will throw off as well a-i draw 05 
the t-lectrical fire, lay a long sharp needle upon the shot. 
and you cannot rlectnse t h e  shot so a5 to make i t  repel 
t h e  r o r h b a l l .  . . . Or fix a needle to the end of a w- 
pended WII barrel, ur iron-rod, so as to point beyond it like 
a liltle bayonet; and ~ h i l e  it reinmas there, the gun-hatic!, 
or rod. cannot by applying t h e  tube to the other end he 
elertrieed so as to give a spark, t h e  fire continually r u n -  
ning out silently a t  the point," 

I can find no evidence that prior to Franklin tlie 
electrical properties of points had been discovered a1 
all. H e  continues: 

"The repellency hetween tlic rnrk-ball and the shot i \  
1ikeivi.e destroyed, I 1  I by sifting fine sand on it; this <lees 
it gradually; (2) by breathing on it; (3) by niakmp a enink? 
about i t  from burning wood: ( 4 )  by candle-lisht, even 
though the candle i s  a t  a foot distance: these do i t  sud- 
denly. . . . T h e  light of a bright coal from a wood fire; 
and the light of a red hot iron do i t  likewise; but not a t  
50 greet a distance. 

"The light of the sun thrown strongly on both cork and 
shot by a looking-glass for a long time together. does not 
impair the repellency i n  t h e  least. This difference between 
fire light and swi-light is another thing that seems new and 
extraordinary to us.*" 

The insight shown in the last three lines. in which lie 
correctly makes particle carriers (ions. we now call 
them) from the match do the discharging while sun. 
light produces no ions and therefore does not dis- 
charge, is unbelievably penetratinq f o r  a date 200 
years hack, though the conception of neutral particles 
hein"rst attracted and then repelled i s  of course defi- 
nitel? urong. 

The next experiment, with its interpretation, is proh- 
ably the most fundamental thing ever done in the field 
of electricity. Get it exactly i n  Franklin's words: 

ENGINEERING AND SCIENCE MONTHLY Page 8 



"1. A person standing on wax, and rubbing t h e  tube, and 
m o t h e r  person on wax drawing the fire, they will both of 
them (provided they do not stand so as to touch one an- 
other) appear to be electrised, to a person standing on the 
floor; that is, he will receive a spark oil approaching each 
of them with his knuckle. 

"2. But if t h e  persons on wax touch one another during 
the exciting of t h e  tube, neither of them will appear to b e  
electrised. 

"3. If they touch one another after exciting the tube, 
and drawing the fire as aforesaid, there will he a stronger 
p a r k  between them than was? between either of them and 
the person on the floor. 

"4. After such strong spark, neither of them discover a n y  
~ l e c t r t c i t y .  

' T h e s e  appearances we attempt to account f a r  thu3- W e  
suppose, as aforesaid, that electrical fire is a common elem?nt 
w e  now call "electrical fire" electrons], of which every one 
i f  t h e  three persons above mentioned has his equal share, 
before any operation is begun with t h e  tube. A. who stands 
on a x  m d  rubs the tube. collects t h e  ~ ~ l t c t r i c a l  fire from 
himself into the glass; and his communication with the com 
mon -stock being cut off by t h e  wax, \ w  body is not again 
mmediately supply'd. B, (who stands on wax likewise) 
passing his knuckle along near the tube, receives t h e  fire 
which was collected by the glass from A ;  and his com 
rnuiut.ation with t h e  (ommon stock being likewise cut off, he 
t I additional quantity received.-To C, stand 
1 on t h e  floor, both appear to be electneed; for he, having 
only the middle quantity of electrical hre, receives a  park 
upon approaching B ,  who has an over quantity; but gives 
n ?  to A. who has a n  under quantity. If A and B approach 
to touch each other, t h e  spark is strortger. becaii-e the dif 
ference between them is greater; after such touch there is 
no p a r k  between either of them ifnd C, because the elec- 
trical fire in all is reduced to t h e  original equality. I f  
they touch while electrising, t h e  equality i s  never de- 
t i v ' d ,  the fire only circulating. Hence have arisen some 
new terms among us: we say B (and bodies l i k e  cirrum. 
ctanced) is electrised positively; A, negatively. Or rather, 
B is clectnsed plus; A, Minus. And w e  daily in our experi- 
ments electrise hodies plus or minus, as we t h i n k  proper.- 
To electrise plus or nunus, no more needs to be known 
than t h ~ s ,  that t h e  parks of t h e  tube or sphere that are 
rubbed. do, i n  t h e  instant of t h e  friction. attract t h e  elec- 
t fire. and therefore take i t  from the thing n i b h m g ;  
the same parts immediately, as the friction upon then, mazes. 
a disposed to give t h e  fire they have received, to any 
body that has less." 

T h e  next two long letters a r e  taken up largely with 
what h e  calls "M. Muschenbroek's wonderful bottle,'' 
accidentally discovered in Leyden one year earlier, 1746, 
nou k n o u n  as the Leyden jar, and with explaining a l l  
such effects just as we do today in terms of the op- 
posite charges o r  the inner and outer coats. Thus, 
to use h i s  exact words: 

"At the same time that t h e  wire a n d  top (inside ?oat) 
of the bottle is electrified positively or plus t h e  bottom 
(outside coat) of thp bottle is electrified negatively or 
m ,  i a c t  proportion: i.e., whatever quantity of elec- 
trical fire is thrown in a t  the top a n  equal quantity goes o u t  
i t  the bottom." And "Again, when the bottle i i  electrised. 
but little of the electrical fire can h e  drawn nut from t h e  
top touching the wire unless an equal quantity can a t  
the samp time get in a t  t h e  bottom. Thus, place a n  dec- 
triced bottle in clean glass or dry wax and yon will not, 
h\ toitching the wire get out t h e  fire from the top." 

These chapters, too. contain the uncannily clever ex- 
periment of showing, just a s  we d o  today, that the charge 
resides in o r  on the dielectric. How many of us realize 
that the familiar classroom experiment of removing the 
coats of a Leyden j a r  and touching each of them. then 
putting them back again. and after that getting a strong 
spark b) connecting the replaced coatings with a wire 
u a s  devised by Benjamin Franklin in 1749? Again, h e  
eavs: - 

T h  t e n t  effect probably did not 3r,se f , ~ " ,  .,,,, < t , f f ~ , ~ " ~ e  ,,I ,lac 
ligtii, h u t  rather from the particles iepardted from the eandte, l~cmx fin,, 
attracted a n d  then repelled, carryiinr off the electric matter w i t h  them 

DECEMBER. 1943 

"There is one experiment more which surprises us, and 
i s  not hitherto satisfactorily accounted for; i t  is this: 
Place a n  iron shot on a glass stand, and let a ball of damp 
cork, suspended by a silk thread, hang in contact with the 
shot. T a k e  a bottle i n  each hand, one that is electrified 
through the hook, the other through the coating: Apply 
t h e  giving wire to the shot, which will electrify i t  positively, 
and t h e  cork shall be repelled; then apply the requiring 
wire, which will take out the spark given by the other; 
t h e n  the cork will return to the shot: Apply t h e  same 
i n  and take out another spark, so will the shot be 
electrified negativelv, and the cork in that shall be re- 
pclled equally as before. Then apply t h e  giving wire to t h e  
shot, and give the spark i t  wanted, so will the cork return: 
Give at another, which will be a n  addition to its natural 
quantity, so will the cork be repelled again: A n d  so may 
the experiment b e  repeated as long as tlif-re is any charge 
n the bottles. Which shows that bodies having less than 
the (ommon quantity of electricity, repel each other, as 
well as those that have more? 
In that last sentence Franklin states clearly that mat- 

ter which had lost its normal amount of electricity was 
self repellent. In modern terms the atom is neutral when 
it has its f u l l  comwlement of electrons. When a n v  of these 
a r e  removed the nuclei repel one another. 

I n  some of his letters, notably the fifth, Franklin goes 
off into long and incorrect speculations as to the dtf- 
ference between the terms "electric bodies per se" and 
" non electric hodies." But this adds to, rather than sub- 
tracts from my own appreciation of him, for no human 
being could possibly have seen correctly all the ele- 

(Continued on Page 16) 

C o p p e r  late line cut appearing as "Plate I" of t h e  
book, illustrating the experiments described in t h e  

Franklin letters t o  Collinson. 

Page 9 



ing these non-ferrous materials into exchanges, pressure 
vessels, etc. This "know how" will be very useful t o  
the new petro-chemical industry. Some examples of 
non-ferrous equipment are: copper or Everdur reaction- 
chambers, nickel salt-handling equipment, Monel or 
Inconel evaporators, and solid Hastelloy (nearly non- 
ferrous) for plastic-compounding. 

Many of the newer cracking and reforming opera- 
tions involve dehydrogenation. I n  these, as well as in 
the direct hydrogenation process, the presence of free 
hydrogen may cause the phenomenon known as hydro- 
gen-penetration. This causes progressive deterioration of 
the steel and to date, I am told, no fully satisfactory 
remedy has been found. Vessels have been made with 
walls twice a s  thick as would otherwise be required, 
but still the hydrogen seeps through. 

Now a word about abrasion. Without referring too 
specifically to the mechanism of the several new cat- 
alytic processes, i t  may be said that at least two of them 
use finely divided solids as catalysts, and these fine 
solids are caused to flow in suspension in fluids. Dur- 
ing this flow, and in subsequent separation ( i n  one 
process), the solid particles act abrasively. Equip- 
ment handling this mixed flow condition may be 
either of abrasive-resistant material like the workable 
low-manganese alloy steels, or, the anti-corrosion clad- 
dings or liners, by virtue of their generally better 
physical properties, hardness and tensile strength, may 
offer long enough economic life. If temperature per- 
mits, one should not overlook the fact that rubber 
linings are often resistant to both abrasion and corrosion. 

CONCLUSION 
The development of the new applied science of petro- 

chemistry is just beginning. As new processes, new re- 
actions, new catalysts are discovered, and new products 
a r e  developed from petroleum there will be more new 
equipment-perhaps unlike any we have yet seen. That 
is the only conclusion with which this article can end. 

Photo on page 1 3  courtesy the Lummus C o .  

Benjamin Franklin 
(Continued f r o m  P a g e  9) 

ments of a huge and thus f a r  completely unexplored 
field, and his wrong steps give him opportunity to show 
his greatness by the way he goes to work to discover 
and to admit his error. Thus, he writes as follows: 

"Query, Wherein consists the difference between an 
electric and a non-electric body? 

"Answer, The terms electric per se, and non-electric, 
were first used to distinguish hodies, on a mistaken sup- 
position that those called electrics per se, alone contained 
electric matter in their substance, which was capable of 
being excited by friction, and of being produced or drawn 
from them, and communicated to those called non-electrics, 
supposed to he destitute of i t :  For the glass, etc., being 
rubb'd, discover'd signs of having it, by snapping to the 
finger, attracting, repelling, etc. and could communicate 
those signs to metals and water.-Afterwards it was found, 
that rubbing of glass would not produce the electric mat- 
ter, unless a communication was preserved between the 
rubber and the floor; and subsequent experiments proved 
that the electric matter was really drawn from those hodies 
that a t  first were thought to have none in them. Then i t  
was doubted whether glass and other hodies called elec- 
tries per se, had really any electric matter in them, since 
they apparently afforded none but what they first extracted 
from those which had been called non-electrics. But some 
of my experiments show that glass contains i t  in great 
quantity, and I now suspect i t  to be pretty equally diffused 
in all the matter of this terraqueous globe. If so, the terms 
e l e c t r i c p e r  se, and non-electric, should he laid aside as 
improper; and ( t h e  only difference being this, that some 

bodies will conduct electric matter, and others will not) 
the terms conductor a n d  nan-conductor may supply their 
place." 

Without doubt the most profound paragraphs in all 
of Franklin's letters a r e  the following, written in 1749: 

"1. The electrical matter consists of particles extremely 
subtile, since i t  can permeate common matter, even the 
densist metals, with such ease and freedom as not to receive 
any perceptible resistance. 

"2. If any one should doubt whether the electrical mat- 
ter passes through the substance of bodies, or only over a n d  
along their surfaces, a shock from an electrified large glass 
jar, taken through his own body, will probably convince 
him. 

"3. Electrical matter differs from common matter i n  
this, that the parts of the latter mutually attract, .those of 
the former mutually repel each other. Hence the appear- 
ing divergency i n  the stream of electrified effluvia. 

"4. But though the particles of electrical matter d o  
repel each other, they are strongly attracted by all other 
matter. 

"5. From these three things, the extreme subtility of 
the electrical matter, the mutual repulsion of its parts, 
and the strong attraction between them and other mat- 
ter, arise this effect, that, when a quantity of electrical 
matter is applied to a mass of common matter, of any 
bigness or length, within our observation (which hath not 
already got its quantity) i t  is immediately and equally 
diffused through the whole. 

"6. Thus common matter is a kind of spunge to the elec- 
trical fluid. And as a spunge would receive no wtfer i j  t h e  
parts of water were not smaller than the pores of t h e  
spunge; and even then but slowly, if there were not a mu- 
tual attraction between those parts and the parts of t h e  
spunge; and would still imbibe it faster, if t h e  mutual a t -  
traction among the parts of the water did not impede, some 
force being required to separate them; and fastest, if, in- 
stead of attraction, there were a mutual repulsion among 
those parts, which would act in conjunction with the a t -  
traction of the spunge. So is the case between the electrical 
and common matter. 

"7. But i n  common matter there is (generally) a s  much 
of the electrical as it will contain within its substance. If 
more is added, i t  lies without upon the surface, and forms 
what we call an electrical atmosphere; and then the body 
is said to be electrified." 

In these paragraphs Franklin states with great suc- 
cinctness what later became known a s  the Franklin one- 
fluid theory, and after 1900 was known a s  the electron 
theory. In his day and f o r  150 years thereafter i t  re- 
ceived very scant consideration in the old world, and the 
so-called two-fluid theory of Aepinus, put forward a 
little later, was universally taught in textbooks the 
world over u p  to the triumph of t h e  electron theory in 
1897 under the active leadership of J. J. Thomson, who 
himself pointed out that this electron theory was i n  es- 
sential particulars a return to the theory put forth by 
Franklin in 1749. For Franklin's electrical matter con- 
sisted of extremely subtle mobile narticles (now called 
negative electrons), which in order to make matter ex- 
hibit its common or neutral properties had to be present 
in each kind of matter (we now say i n  each kind of 
atom; but the atomic theory had not been formulated in 
1749) in a oarticular number. an increase in which 
number made it exhibit electrification of one sign, a 
decrease, a n  electrification of the opposite sign. In 
Franklin's theory only one kind of electrical matter 
was mobile, the other sign of electrification appeared 
when the mobile kind was removed so that it could no 
longer neutralize the effect of the opposite kind which 
inhered in the immobile part of the matter (i. e., i n  the 
nucleus). 

The Franklin theory was mathematically identical 
with the two-fluid theory, but while the former was a 
definite and profound physical theory the latter was a 
hold-over from medieval mysticism. It came from the 

Page 16 ENGINEERING AND SCIENCE MONTHLY 



age of the so-called "imponderables"-an imponderable 
or weightless heat theory, the caloric-and the impon- 
derable electric fluids. Such vague, tenuous, contradictory 
ideas were i l l  at home in the highly realistic, practical 
mind of Franklin. They were justified, like Faraday7s 
lines of magnetic force, as analytical conveniences but 
not as physical realities. Franklin introduced a definite 
physical theory which rendered unnecessary such fan- 
tastic conceptions as two weightless and hence non-ex- 
istent fluids introduced for purely ad hoc purposes, and 
then told to destroy each other, also for ud hoc purposes. 

Let us now return to Franklin's discussion of points 
and their properties of throwing off or drawing off the 
electrical fire. He says, very modestly and wisely: 

"These explanations of the power and operation of 
points, when they first occurred to me, and while they first 
floated in my mind, appeared perfectly satisfactory; but 
now I have written them, and considered them more close- 
ly, I must own I have some doubts about them; yet, a s  I 
have at present nothing better to offer in their stead, I do 
not cross them out; for even a bad solution read, and its 
faults discovered, has often given rise to a good one, i n  the 
mind of an ingenious reader." 
Then in the next paragraph note how clearly lie sees 

the necessity of eliminating unnecessary hypotheses, i .  e., 
he adopts the scientific principle of "minimum liy- 
pothesis." 

"Nor is it of much importance to us, to know the nian- 
ner in which nature executes her laws; it i s  enough if we 
know the laws themselves. I t  is of real use to know that 
china left in the air unsupported will fall and break; b u t  
how it comes to fall, and why i t  breaks, are matters of 
speculation. I t  is a pleasure indeed to know them, but we 
can preserve o u r  china without it." 

He then describes some discharging effects of uoints " L. 
conducted on a larger scale than he had before at- 
tempted, and in a later paper dated November 7, 1749, 
he enumerates all the known points of resemblance he- 
tween lightning and electricity, and~concludes with the 
comment: 

"The electric fluid is attracted by points. We do not 
know whether this property be i n  lightning but since they 
agree in all points in which we can compare them, i t  is 
not improbable that they agree likewise i n  this. Let the 
experiment be made." 

In June, 1752, he made it, carrying out in a shed with 
his son the experiment which he describes as follows 
in his letter of October 19, 1752, to Peter Collinson. 

"As frequent mention is made in public papers from 
Europe of the success of the Philadelphia experiment for 
drawing the electric fire from clouds by means of pointed rods 
of iron erected on high buildings, etc. I t  may be agreeable to 
the curious to be informed that the same experiment has 
succeeded in Philadelphia, though made in a different and 
more easy manner, which is as follows: 

"Make a small cross of two light strips of cedar, the 
arms so long a s  to reach to the four corners of a large 
thin silk handkerchief when extended; tie the corners of 
the handkerchief to the extremities of the cross, so you have 
the body of a kite; which being properly accommodated 
with a tail, loop, and string, will rise in the air, like those 
made of paper; but this being of silk is better to bear 
the wet and wind of a thunder gust without tearing. To the 
top of the upright stick of the cross is to b e  fixed a very 
sharp pointed wire, rising a foot more above the wood. To 
the end of the twine, next the hand, i s  to be tied a silk 
ribbon, and where the silk and twine join, a key may be 
fastened. This kite is to be raised when a thunder-gust 
appears to be coming on, and the person who holds the 
string must stand within a door or window, or under some 
cover, so that the silk ribbon may not be wet; and care 
must be taken that the twine does not touch the frame 
of the door or window. As soon as any of the thunder 
clouds come over the kite, the pointed wire will draw the 
electric fire from them, and the kite, with all the twine, 
will be electrified, and the loose filaments of the twine will 
stand out every way, and he attracted by an approaching 

On Christmas, a s  every day, 

we'll "keep 'em rolling" 

Tm HEAVY, u R m T  T R A M  of war will roll as usual over 
our rails through the twenty-four hours of December 25th. 

S.P. engineers and firemen, conductors, dispatchers, yard- 
men, brakemen-thousands of men and women of the many 
score crafts required to operate the West's biggest railroad 
-will be at their posts of duty. 

With the "tools" of our trade-locomotives, cars, tracks 
and signals-we will move the war trains. We will move 
service men on furlough a n d  members of their families, 
and an enormous volume of food and industrial shipments. 

Yes, the people of our railroad will be hard at work on 
Christmas. But for us this Day will have a bright and 
special meaning-because you folks along our lines have 
made the Christmas Spirit so real to us. 

The friendly Southern Pacific 
@ D O N ' T  P L A N  O N  T  R  A  V E L  I  N  G O V E R  T H E  H O L I D A Y S  - 

L E T  A  M A N  I N  U N I F O R M  H A V E  Y O U R  T R A I N  S E A T  O R  B E R T H  

DECEMBER, 1943 Page 17 



WANTED 
for the 

PHILCO 

STAFF 
 RADIO-ELECTRONICS-ELECTRICAL 

ENGINEERS 
Men with degrees in electrical 
engineering or comparable experi- 
ence in radio and television. 

MECHANICAL ENGINEERS 
Men with college degrees o r  com- 
parable experience in the engineer- 
ing aspects of electrical appliances, 
and in designing small machinery. 

DESIGN ENGINEERS - DRAFTSMEN 
Men with experience in mechanical 
designing, especially of small metal 
parts and of the automatic ma- 
chinery t o  mass-produce them. 

PRODUCTION ENGINEERS 
Including electrical and mechani- 
cal engineers familiar with any 
phase of radio, radio-phonograph 
and television production. 

PHYSICISTS 
Must have science degree in 
physics. Some practicalexperience 
i n  radio i s  desirable. 

F OR these and other key posi- tions-senior and junior engi- 
neers for research, project and 
design work, physicists and mathe- 
maticians - we are looking for 
men who are thinking about the 
future. Right now there is plenty 
of urgently needed war work t o  
do. But some day peace will return 
-and Philco is planning t o  be 
ready for i t  with advanced Radio, 
Television, Refrigeration and Air- 
Conditioning products. This may 
be your opportunity t o  get ready 
for it too. 

W R I T E  US TODAY 
Qualified men not now engaged in 
work requiring their full talents, are 
invited t o  write us in detail a s  t o  their 
experience, education, family and draf t 
status, and salary. Letters will be 
treated in strict confidence. 

Employment subject to local W.M.C. r u l e s .  

WHITE T O  MR. GEORGE DALE 

PHILCO 
C O R P O R A T I O N  

Philadelphia 34, Panna. 

Principal credit for maintaining the production sched- 
ule regardless of delays was due to the fine spirit of co- 
operation between the contractors, represented by Proj- 
ect Manager R. F. Rasey, and the U. S. Engineering 
Department. J. G. Morgan was resident engineer for 
the government. 

finger. And when the rain has wet the kite and twine, so 
that it can conduct the electric fire freely, you will find it 
stream out plentifully from the key on the approach of 
your knuckle. At this key the phial may be charged; and 
from electric fire thus obtained, spirits may be kindled, 
and all the other electric experiments be performed, 
which are usually done by the help of a rubbed glass globe 
or tube, and thereby the sameness of the electric matter 
with that of lightning completely demonstrated." 

I n  a further letter written in September, 1753, he 
says: "In September 1752 I erected an iron rod to draw 
the lightning down into my house, in order to make 
some experiments on it." H e  carried on these experi- 
ments for some months to learn whether the clouds 
were positively or negatively electrified, and after many 
trials he says: 

"I concluded that the clouds are always electrified 
negatively, or have always in them less than their natural 
quantity of the electric fluid. 

"Yet notwithstanding so many experiments, it seems I 
concluded too soon; for at last, June the 6th, in a gust 
which continued from five o'clock P. M. to seven, I met 
with one cloud that was electrified positively, though several 
that passed over my rod before, during the same gust, 
were in the negative state." 

The foregoing shows what most commendable scien- 
tific care he took in his experiments and what caution 
he used in drawing conclusions. 

^ Ã ˆ  

But he did not stop with making scientific experi- 
ments. His active and practical mind was not satisfied 
until he had applied it to the useful end of the invention 
of the lightning r o d  a s  indicated in the first paragraph 
of the letter of October 19, 1752, quoted above. 

After his definite proof of the identity of lightning and 
electricity he was recognized by the most distinguished 
English scientists by being elected to the Royal Society, 
and was presented for the year 1753 the Copley medal 
of the Society, the highest honor within the gift of the 
world's most illustrious scientific body. 

Santa Fe Dam 
( C o n t i n u e d  from Page 6) 

1943; at which time heavy and prolonged rains caused 
flood conditions of major proportions to develop along 
the river' channel. During this week the highest rain-" 
fall intensity recorded to date in the United States 
was measured in the mountains a few miles east of the 
dam, where 25 inches of rain fell i n  2 4  hours. Tre- 
mendous quantities of material were washed down 
into the reservoir area, and wide gullies were cut in 
the upper end of the reservoir borrow pit. Floating 
debris partially choked up the trash racks, causing the 
water to be backed up in the reservoir and threatening 
two of t h e  grizzly plants with inundation, but quick 
work of removing trash with a dragline eliminated the 
hazard. Construction work was halted by this and 
succeeding storms for a total of five weeks and clean- 
up work continued for many weeks more; yet in spite 
of delays, construction was completed four months ahead 
of schedule. 

Page 18 E N G I N E E R I N G  AND SCIENCE M O N T H L Y