Feeding America – the Historic American Cookbook Project is a joint project of Michigan State University and Michigan State Museum to not only collect influential American cookbooks but to make them available in either pdf format or as searchable text. The cookbooks range in date from 1798 (Amelia Simmons) to 1922.
Who can resist Breakfast, Lunch and Tea by Marion Harland (actually Mary Virginia Terhune) printed in 1875. See her recipe for Ambushed Trifle and she writes at length about beating eggs, etc.
I have another 1876 book, Practical Cooking and Dinner Giving by Mary Henderson which is filled with fairly sophisticated recipes, simple six course luncheons for ladies and grand dinners. The ladies drank very well and lunch included Chateau d’Yquem. I certainly paid less than $20 for it and it is highly recommended.
In addition to the individual pages, or the entire scanned book as a pdf, you can also seach for recipes by name and ingredient, browse the books by date, author or categories. A great project and fun to look through.