The Washington times. [volume] (Washington [D.C.]) 1902-1939, 1923-04-08
AUTO HEADLIGHTS
UNDERGOING TESTS
Bureau of Standards Making
Exhaustive Study of
Light Question.

i "A headlight which will brilliantly
i illuminate the road ahead without
i glaring in the eyes of drivers conn
! ing from the opposite direction. is
1 the ideal of motorists. Several de-
vices now in extensive use accom-.
plish this object.
| The Bureau OF Standards has
been making Etests ION automobile
headlights with view to devising
simple methods of testing lights on
| the road, and keeping them in ad.
1 tustment, so they viii give good
distribution of light.
A method OF testing Is used which
requires nothing more complicated
| than a screen of canvas or other
suitable material on which three
| lines are drawn. One of these Is
horizontal and at approximately the
same height as the headlights of
the car; the other two are vertical
and as far apart as the headlights.
The car is placed at q distance OF
twenty-five feet with its lights shin
ing on the screen. The region be-
low the horizontal line should be
brilliantly illuminated, with the
illumination extending only a short
distance above and then fading to
an intensity slightly greater than
that. obtained by using DINNERS!
Some light is required in this
region, but should not be bright
enough to be glaring. The bright
light should not rise as high on the
sides as it does at the center.
DINNERS ARE DANGEROUS.
In passing tests made at the bu-
reau It was shown that two cars
using good lenses could safely pass
without using DINNERS. The lights
did not glare in sthe eyes Of ap-
| the road beyond the other car
with sufficient brilliancy to permit
| the driver to see what was there.
When DINNERS are used, on the
other hand, the road beyond the app
preaching car is left in complete
darkness, and not until he has
passed It can the driver see what is
4 there.
A case is told of where several
school girls were killed because of
this. They passed behind one ca.
in crossing the road and one COM
ing from the opposite direction ran
| them down.. In this case both cars
were using DINNERS. On another
occasion a car smashed into high
curling.
DESIRABLE LENSES.
Lenses of the best design appear
Ito be made up of rectangular or tri-
angular sections, and these will be
found slightly curved on one sur
face, the axis of the curve being
vertical, and the top of the sections
are thinner than the bottom.
Certain types or reflectors will
give approximately the same distri-
button as these lenses, and with
such a plain glass is used.
/ Lenses of poor design scatter the
light in all directions. Such lenses
| do not give sufficient illumination
on the road, and are almost sure to
give a glaring light in the eyes OF
approaching drivers. A driver
should always consult his police de-
partment before buying lens. and
obtain list of approved devices.
HEADLIGHTS MUST
BE ADJUSTED.
Proper adjustment OF the head
lights is of equal importance with
| proper design. The lamp must. be
in focus. In modern types this is
readily accomplished by means OF
a screw on the back of the casing
/ where it can be readily gotten at.
A few types still on the market re.
quire the lens to be removed for
adjusting, and this type is naturally
much more difficult to adjust.
1t is also necessary to have the
! headlights properly aligned. The