DIFFERENTIAL ENGINE

BABBAGE'S DIFFERENTIAL ENGINE

          In 1812, another interesting development took place in the history of computers. Charles Babbage, an English Mathematician, invented the Differential Engine. Babbage is called his device a Differential engine because it was based on the difference tables of the squares of numbers. For example, the following table shows the level difference between values of Y in the formula i.e. Y=X²

Table showing Level difference

Value of X	Value of Y	1st level difference	2nd level difference
0	0	1	2
1	1	3	2
2	4	5	2
3	9	7	2
4	16	9	2
5	25	11	2

As shown in the table, the second level difference is constant (i.e. 2). Y can be found for any value of x by adding (for x=5) as:

y=2+7+16=25

Babbage wanted to calculate Polynomial functions using the method of differences but such machine was to have hundreds of gears, shaft and counters. Unfortunately, the differential engine was not completed.