Primary School Science in the Public Domain

I spent much of my weekend recovering from the week...and reading science books.  Yes, science books.  Science and I have never really gotten along.  Oh, I passed fine in school, but that was due to my ability to memorize for a test and then quickly forget everything I "learned" as soon as the test was done. Terrible, I know!  =/  But, that is in the past.
In the "now" in keeping with the CM philosophy of giving children a love for learning, I wanted to find something "living" for science for my kids.  I know there are some great curricula out there, like Apologia or Answers in Genesis.  But, I like to see what I can find in the public domain.  I was on Google books this week and found some delightful books that I pre-read/scanned this weekend.
Probably my favorite one is The Spark of Life by Margaret Warner Morley.  It teaches that subject to kids.  You know, the one us parents don't have a clue as to how to approach.  The author begins by explaining how plants reproduce, then moves on to higher life forms, eventually getting to birds, and mammals.  Then, people.  This book is very gentle.  It doesn't say anything "embarrassing" but simply gives the facts in a very wholesome, honorable way.  It's a great first book on this topic.  More will need to be introduced later, of course, but I think this will satisfy the curiosity of early elementary kids who want to know where babies come from.  She also wrote a book for parents called The Renewal of Life.  This book goes into her philosophy of telling children the truth about this delicate topic.  This was also a good read, although I didn't read every single word.
The second favorite book I found is a real gem!  The Child's Book of Nature, 3 books in one, by Worthington Hooker.  The version on Google books is free, of course, but it does have some missing letters at times.  You can purchase a printed copy on Amazon, but I prefer free...unless I find it at a thrift store or a rummage sale.  The first book is a botany book, the second a book about human and animal life, and the third a general science book.  I have read through the first two books with much delight.  I love the author's style of writing.  I can imagine using these books along with a modern, colorful science book with pictures of the parts of plants, the human body, etc.
I'm not sure if/when we'll use these books, but I like to have them bookmarked just in case.  I'm tentatively thinking of using at least The Spark of Life when we finish our current science books.  Anyway, this was a fun weekend project for me.  I love the thrill of finding free living books and seeing where God might be leading us!