After reading an effusive description of the technological achievement of the linotype machine, I started reading into it.
What I've learned is that it was a pretty cool machine, but mind-bogglingly so for when it was first made in the 1880's. It was also pretty cool that the technology was in use all the way up to the 1970's.
An image search shows that the machines changed very little over time, except that all the early images show it as belt driven:
https://www.google.com/search?q=linotype+machine&hl=en&tbo=u&tbm=isch&source=univ&sa=X&ei=GiGcUOmnEOWW2AWb54HABA&sqi=2&ved=0CDcQsAQ&biw=1117&bih=483
It was primarily a high speed sorter of tiny letter molds, coupled with a really ingenius high-speed caster. There was a fairly modern-looking keyboard that caused letter molds to be ejected from a big tray. They slid down a ramp into a line build-up bar. Spacers were wedges dropped in from a different source. Then the whole built-up line of molds would be mechanically moved to a different section of the machine, the spacing between words would be adjusted using the wedges to produce full allignment, then the face of the line would be pressed in a tight seal onto a channel into which hot metal would be flowed, the resulting slug would then undergo a surprising amount of further mechanical processing before being ejected, all at an incredible number of lines per minute. The built up line would then get all its pieces sorted back into the starting tray using a wonderful keying mechanism. Then folks had to set the slugs up on a printing press by hand. It's a pretty sobering example of a nearly impossibly complex job being enabled by automating selected parts of the process.
Some links, starting from the wikipedia article:
http://en.wikipedia.org/wiki/Linotype_machine
and
http://en.wikipedia.org/wiki/Ottmar_Mergenthaler
Which seems to have mostly been lifted from one Maryland history web page:
http://www.zionbaltimore.org/history_people_mergenthaler.htm
Here are a couple of perspectives on the genius of this machine. The 8th wonder of the world:
http://ntluckie.com/#The-Linotype-Machine
A museum piece with an interesting placard quantifying the complexity of this machine -- "it had more moving parts when it was constructed than anything else ever built by man" :
http://www.seobythesea.com/2012/08/indexing-recent-content-in-search-engines/
A brief summary of the mechanism:
http://www.woodsidepress.com/LINOTYPE.HTML
A modern person's attempt to understand the workings of the machine, particularly the sorting mechanism:
http://www.circuitousroot.com/artifice/letters/press/compline/studies/matrices/matrix-teeth/tooth-chart/index.html
Here is one of hundreds of linotype youTube videos. I love how this shows the mechanical action:
http://www.youtube.com/watch?v=PRYxOs1oCRY
