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Widely used throughout the 20th Century by schools, churches, fan clubs, and other small organizations, Spirit Duplicators or "Ditto" machines allowed small runs of documents to be copied cheaply and quickly. Often conflated with mimeographs, they were in fact a distinct technology, used a master sheet printed with dye-bearing wax instead of liquid ink. Paper passing through the machine was wetted with a solvent and pressed against the master sheet, causing some of the dyed wax to dissolve and transfer onto the paper.

Gestetner Cyclostyle (Mimeograph) Video: https://www.youtube.com/watch?v=NdBSYUbaAZg&pp=ygUJZ2VzdGV0bmVy

0:00 Introduction
1:26 "Ditto" and "Banda" as Genericized Trademarks
2:15 Rex Rotary R11 - History
2:56 Rex Rotary R11 - External Controls
3:17 Creating Master Sheets
4:44 Correcting Master Sheets
5:21 Loading the Master Sheet
6:00 Solvent ("Duplicator Fluid") System
7:35 Loading Paper/Final Setup
8:31 Making Copies
9:05 Other Design Features / Internal Mechanism
9:52 Design Variations
10:12 Master Sheet Variations
11:00 Impact of Spirit Duplicators
11:23 Outro

SOURCES: 

https://www.mimeographrevival.com/advertisements/
https://blog.lib.uiowa.edu/speccoll/2021/07/23/spirit-duplicators-early-20th-century-copier-art-fanzines-and-the-mimeograph-revolution/
https://collections.museumsvictoria.com.au/articles/2636
https://cool.culturalheritage.org/coolaic/sg/bpg/annual/v17/bp17-05.html
https://www.kickstarter.com/projects/237843661/cheap-copies/posts/3241093
https://pastbrands.com/brands/ditto-machines-aroma-in-the-school-hallway-meant-quiz-time/