Cash Flow Information (Schedule of supplemental disclosure) (Details) - USD ($)	6 Months Ended
	Jan. 31, 2022	Jan. 31, 2021
Cash Flow Information
Interest paid, net of capitalized interest of $14,440 (2022) and $34,390 (2021)	$ 160,846	$ 147,196
Income taxes paid (refunded)		(23,041)
Capitalized interest	$ 14,440	$ 34,390