sales scatter graphs

I am unaware of the person(s) who came up with this idea for scatter graphs and it's hard to find this information out because several resources have used the idea

(I'd be grateful if someone could let me know)

the commodities and their associated scatter graphs usually make sense to students in terms of the explanatory variable

the (product-moment) correlation coefficients, using Excel, in the order presented are:

1.    0.94
2.    0.87 (negative)
3.    0.22
4.    0.31