This exact test was described in detail to the readers of A Guide to Royal Success in Baking, written by Standard Brands Incorporated, the makers of Royal Baking Powder. Here is their guide, truncated to show popular pastry & baked goods. The full guide is listed in the book.
Paper Test: Although this test is not as accurate as either the oven control or thermometer, it will prove helpful when other means of testing the oven are not available. Place a piece of white unglazed paper in center of oven after it has been lighted for ten minutes. The heat is correct when the paper browns in the time specified below.
Of course, we don't have to worry about this kind of calibration or testing now, but it is useful to know how they did it in the early 1900's.
- Quick Loaf Breads - at 375 degrees F. [moderate oven] - 1 1/2 minutes
- Biscuits - at 475 degrees F. [hot oven] - 1/2 minute
- Cookies - at 400 degrees F. [moderate hot oven] - 1 minute
- Pastry Shells - at 475 degrees F. [very hot oven] - 1/2 minute
- Meringue - at 325 degrees F. [slow oven] - 2 minutes