Keep in mind, I MIGHT BE WRONG IN MY OPINIONS ABOUT THE LAW.
I have acquired these photos by scanning from textbooks, chemical history books, journals, and newsletters. In no case have I sought permission to use a photo nor have I investigated the copyright status of any photo. I have kept only minimal documentation of the source for each photo.
I am using these photos under my understanding of "fair use" in copyright law. The photos are being provided as an educational benefit to viewers and are not intended for reproduction in a venture for profit. I have never used, nor will I ever use, these photos in any situation where someone has to pay before viewing.
I cannot give anyone permission to use these scans in their paying venture. I do not own the copyright to any photo, whatsoever. If you wish to use one of these photos, please do not download my scan, but work with your publisher to determine the copyright holder and obtain permission from them for usage.
If you wish to use a photo on a handout to your class or link to the photo from your site, then I think your action falls under "fair use."
However, I am not a lawyer. I MIGHT BE WRONG IN MY OPINIONS.