<?xml version="1.0" encoding="utf-8"?><mads xmlns="http://www.loc.gov/mads/" xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.loc.gov/mads/
mads.xsd"><authority><topic authority="http://AATesaurus.cultura.gencat.cat/aat/getty_en">difference engines</topic></authority><related type="broader"><topic>calculating machines</topic></related><variant type="other"><topic>difference engine</topic></variant><variant type="other"><topic>engines, difference</topic></variant> <note xml:lang="en"><![CDATA[ Calculating machines, now historic, that were able to produce tables of values for arithmetic functions. The machine was designed by English inventor and engineer Charles Babbage in 1822, and a working model was built in 1853 by George and Edward Scheutz.  ]]></note></mads>