Theatre Design & Technology - Dec 1969 - 25

Glass Properties Important to
Stage and Studio Lighting
JOHN P. HOXIE, Corning Glass Works
Corning, New York
Mr. Hoxie's paper is based on a presentation before
the Illuminating Engineering Society's annual Symposium on Theatre, Television and Film Lighting,
held May 26-27, 1969. Editor

Glass is the envelope material common to
all lights used in the studio, stage or outdoor photography. This article discusses
briefly the properties of glass which are vital
to various classes of usage_
Starting with the most rudimentary source,
the carbon arc which modern technology
has been able to maintain as our most
powerful lighting device, we locate a fresnel lens about 8" from a 200 to 300 ampere arc crater. This lens accomplishes
(1) a closure for the light producing cavity,
(2) efficiently controls the direction of light
emanation, and (3) protects skin and eyes
from burning by the ultraviolet emission.
These glass functions are inherent in all
high energy lighting devices for this field
of application whether they are incorporated
into a single piece of glass or distributed
among several components.

It is important to understand the importance
of low coefficients of thermal expansion to
lamp envelope manufacture. We employ a
scale of numbers common to the industry.
In brief, we express the coefficient of
linear expansion in parts per million per
degree centigrade which gives us numbers
between 1 and 100. That is, numbers we
multiply by 10'7 power. Ordinary nonheat resisting bulb glass has an expansion
of 92, borosilicate glass as used in Pyrex
brand lenses and "hard glass" projection
bulbs is 36. Quartz is 6 x 10- 7 per degree
C., or 6 on the same scale.
"Pyrex" and "Vycor" are registered trade names.

Laboratory rig for determining coefficient of
glass expansion

With the hermetically sealed source enclosure (which may house either an incandescent filament or a gaseous discharge),
there is not only the tendency to destroy
that enclosing bulb by termal stresses due
to uneven heating, but as well the corrosionlike attack by hot interior gases which
becomes more severe as we approach the
softening point of the glass. High intensity
light-producing reactions are among the
most destructive processes known to man
and each advance in light source technology has called for more durable lamp
envelopes.
As a measure of heat resistance we rate
glasses according to how Iowa coefficient
of expansion they have. A lens made of
very low expansion material will experience
less stress between its hottest and cool er
zones, therefore it runs less danger of
breakage.
Expansion coefficient is determined in the
laboratory on glass rod samples. A rod is
successively held in a cold chamber, then
in a hot chamber, and the amount of elongation noted as the rod goes from a temperature such as O°C to 300°C. (See photo.)

~

THEATER DESIGN AND TECHNOLOGY

Quartz is a pure sil ica glass derived either
from selected natural deposits or refined
industrially by chemical procedures. By virtue of its purity, it transmits the ultraviolet to a spectral degree about equal to
the air around us. This means that light
coming to us from the sun and passing
through a thick layer of atmosphere, including ozone in the upper regions, has
more of its UV removed than lamp light
through quartz. Depending upon the amount
of UV generated, a quartz lamp without
shielding may result in sun burn or eye
damage.

DECEMBER,1969



Table of Contents for the Digital Edition of Theatre Design & Technology - Dec 1969

Contents
Theatre Design & Technology - Dec 1969 - 1
Theatre Design & Technology - Dec 1969 - 2
Theatre Design & Technology - Dec 1969 - 3
Theatre Design & Technology - Dec 1969 - Contents
Theatre Design & Technology - Dec 1969 - 5
Theatre Design & Technology - Dec 1969 - 6
Theatre Design & Technology - Dec 1969 - 7
Theatre Design & Technology - Dec 1969 - 8
Theatre Design & Technology - Dec 1969 - 9
Theatre Design & Technology - Dec 1969 - 10
Theatre Design & Technology - Dec 1969 - 11
Theatre Design & Technology - Dec 1969 - 12
Theatre Design & Technology - Dec 1969 - 13
Theatre Design & Technology - Dec 1969 - 14
Theatre Design & Technology - Dec 1969 - 15
Theatre Design & Technology - Dec 1969 - 16
Theatre Design & Technology - Dec 1969 - 17
Theatre Design & Technology - Dec 1969 - 18
Theatre Design & Technology - Dec 1969 - 19
Theatre Design & Technology - Dec 1969 - 20
Theatre Design & Technology - Dec 1969 - 21
Theatre Design & Technology - Dec 1969 - 22
Theatre Design & Technology - Dec 1969 - 23
Theatre Design & Technology - Dec 1969 - 24
Theatre Design & Technology - Dec 1969 - 25
Theatre Design & Technology - Dec 1969 - 26
Theatre Design & Technology - Dec 1969 - 27
Theatre Design & Technology - Dec 1969 - 28
Theatre Design & Technology - Dec 1969 - 29
Theatre Design & Technology - Dec 1969 - 30
Theatre Design & Technology - Dec 1969 - 31
Theatre Design & Technology - Dec 1969 - 32
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2020winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2020winter_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2019fall_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2019fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2019summer_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2019summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2019spring_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2019spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/usitt_techexpoguide_2019_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/usitt_techexpoguide_2019
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2019winter_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2019winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2018fall_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2018fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2018summer_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2018summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2018spring_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2018spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2018winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2017fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2017fall_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2017summer_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2017summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2017spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2017spring_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/usitt_techexpoguide_2017_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/usitt_techexpoguide_2017
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2017winter_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2017winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2016fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2016summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2016spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2016spring_public
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2016winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2015fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2015summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2015spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2015winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2014fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2014summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2013winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2013summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2013fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2013spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2012winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2012fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2012summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2012spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2011winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2011fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2011summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2011spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2010winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2010fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2010summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2010spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2009winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2009fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2009summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2009spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2008winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2008fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2008summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2008spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2007winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2007fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2007summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2007spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2006winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2006fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2006summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2006spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2005winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2005fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2005summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2005spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2004winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2004fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2004summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2004spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2003winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2003fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2003summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2003spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2002winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2002fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2002summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2002spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2001winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2001fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2001summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2001spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2000winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2000fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2000summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_2000spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1999winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1999fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1999summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1999spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1998winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1998fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1998summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1998spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1997winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1997fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1997summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1997spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1996winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1996fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1996summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1996spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1995winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1995fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1995summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1995spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1994winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1994fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1994summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1994spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1993winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1993fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1993summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1993spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1992winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1992fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1992summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1992spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1991winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1991fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1991summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1991spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1990fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1990summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1990spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1989winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1989fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1989summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1989spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1988winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1988winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1988fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1988summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1988spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1987winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1987fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1987summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1987spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1986winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1986fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1986summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1986spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1985winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1985fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1985summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1985spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1984fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1984summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1984spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1983winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1983fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1983summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1983spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1982winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1982fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1982summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1982spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1981winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1981fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1981summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1981spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1980winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1980fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1980summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1980spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1979winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1979fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1979summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1979spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1978winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1978fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1978summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1978spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1977winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1977fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1977summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1977spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1976winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1976fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1976summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1976spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1975winter
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1975fall
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1975summer
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1975spring
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1974Dec
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1974Oct
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1974May
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1974Feb
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1973Dec
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1973Oct
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1973May
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1973Feb
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1972Dec
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1972Oct
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1972May
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1972Feb
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1971Dec
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1971Oct
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1971May
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1971Feb
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1970Dec
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1970Oct
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1970May
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1970Feb
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1969Dec
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1969Oct
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1969May
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1969Feb
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1968Dec
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1968Oct
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1968May
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1968Feb
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1967Dec
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1967Oct
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1967May
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1967Feb
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1966Dec
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1966Oct
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1966May
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1966Feb
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1965Dec
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1965Oct
http://www.nxtbook.com/nxtbooks/hickmanbrady/tdt_1965May
http://www.nxtbookMEDIA.com