Who owns a copyright on a scanned work? If there is a work that is out of copyright (was published in the 1800s) but I can only find it in an online repository, can the repository claim a copyright or other limitation on my use of their scanned copy?
In the US, the original author still owns the copyright, unless the original work was out of copyright (in which case no one owns the copyright): copyright is not granted for just pressing a "scan" button, and mechanical reproductions are not eligible for copyright (copyright protects creativity, and a scan involves zero creativity). To quote 313.4(A) ("Mere Copies") of the Compendium of US Copyright Office Practices, Third Edition: A work that is a mere copy of another work of authorship is not copyrightable. The Office cannot register a work that has been merely copied from another work of authorship without any additional authorship. [...] Examples: [...] Photocopying, scanning, or digitizing a literary work. That doesn't necessarily mean the repository can't put any restriction on your use of the copy; the repository may have a terms of service. Terms of service are rooted in contract law, not copyright; just because the work is in the public domain, doesn't force the repository to show it to anyone who asks, and they can force you to agree to a contract first. The enforceability of that contract is fact-dependent.
The creator of the derivative work has copyright in the derivative work. The copyright would protect only the new elements of the derivative work. Wikipedia is a good place to start. In the case of a book with updated grammar, depending on the extent of the changes, it would probably be easier to copy the original directly than to eliminate the updates from a copy of the derivative work.
The text and content (including all diagrams and illustrations) of the 1847 work (and of any other work published in 1847) are in the public domain in the US and everywhere in the world. You may freely use them verbatim or in any modified form that you wish. You are not even legally required to credit your source, although not to do so would be unethical, in my view. The version by Nicholas Rougeux that is linked to in the question has the licensing statement: Posters and website design are copyright Nicholas Rougeux. All other content and diagrams are under the Creative Commons Attribution-ShareAlike 4.0 International license (CC BY-SA 4.0). This will not apply to any content copied from the 1847 version, of course. You may use any of the new content and diagrams so released, or make and use derivative works based on those elements, provided that you comply with the CC BY-SA 4.0 license. This has a number of provisions, but the major ones are that you must release your work under the same license, must acknowledge your source work, and must not impose any additional conditions or restrictions on users of your derived work. These are spelled out in sections 3.a and 3.b of the license (linked above). Please read the full terms if you intend to use this license. If this procedure will satisfy your purpose, you do not need any further permission from Nicholas Rougeux, nor to pay any fees or royalties to him. If you do not choose to place your work under a CC BY-SA 4.0 license, then you must not use the diagrams from Rougeux's version, nor modified versions directly based on them, nor an overall design clearly and directly based on the original design of that version, unless you secure permission from Rougeux (or the current copyright holder of Rougeux's version, whoever that may be). Given that Rougeux chose to release under a CC BY-SA 4.0 license, he may well be unwilling to grant permission under a different license, but that is his choice to make. Exception: in the US, you may use content from the Rougeux version to the limited extent permitted by fair use. This is not likely to cover the use of all or a large number of diagrams, particularly for a competing version of the same base work. Without specific information on how much content you would be using from that version, and how similar it would be to the original, no one can reliably determine if fair use would apply or not, but fair use is most likely to apply when a strictly limited amount of content is reused, and particularly when it is used for a different purpose than the original. Also, fair use is a strictly US legal content, and a work that might be held to be fair use by a US court might be considered an infringement by the courts of some other counties. Other countries have their own exceptions to copyright which are different in scope and terms from fair use. Many of them are significantly narrower. Note that a work posted to the internet is in effect published in all countries, and a copyright holder might choose to sue in any country s/he pleases. US courts might well enforce such a judgement even if it would not have been the judgement of a US court. Rogeux (or any other creator of a new edition) can have no copyright in elements already present in Byrne's 1847 work. Any similarity to Rogeux's work that is because of a similarity to Byrne's 1847 work is not copyright infringement. But any new elements introduced by Rogeux (or anyone else), including the manner of adding interactivity to a diagram, may well be protected by copyright (although the idea of having an interactive version of the diagram will not be). Any new or significantly modified text or diagrams introduced in a later version will be protected. As to any other versions of the 1847 &quot;Byrne's Euclid&quot; that may have been published, the publishers gain no copyright over the original 1847 work or any of its elements, including text, diagrams, or color scheme. Provided you do not use any original content newly introduced in such editions, you do not need to secure any permission from, or pay any fee to, the copyright holders of such editions. However, you may not use any such original content, or modified versions clearly based on such original content, without permission, unless an exception to copyright, such as fair use, applies. All that I said above about fair use would then apply. A copyright holder may grant or refuse permission to use a protected work or create a derivative work on any terms that s/he chooses, and charge any fee or royalty rate s/he thinks proper. Lack of response to a request for permission must be treated as if the response was &quot;No&quot;.
All your work is yours. They've made it very clear it wasn't a work for hire, so it's yours. They can't copyright any of their ideas. You can't copyright an idea. Only specific creative elements authored by them and present in your work could be covered by copyright. You didn't use their block diagrams. I don't see how references to other sites to look at would constitute a creative element they authored. That said, you probably want to talk to a lawyer and get a written legal opinion that you can rely on.
This sounds completely incorrect to me. First, subsequent research is not normally a "derivative work" for the purpose of copyright, since copyright doesn't protect your ideas but only the particular form in which you have expressed those ideas. Second, as the owner of the copyright, you can permit anyone to make any sort of copy or derivative work, or sell, assign, or license the ability to do so to other parties, without regard to whether the work has been published. The real reason that nonpublication of your work would stifle further research is that researchers will not have access to it.
Exactly the same way it works over all other content There are no special classes of copyright, there’s just copyright. What a user of a service may do with copyright materials will be spelled out in the licence. If there is no licence, then they are left with fair use/fair dealing.
Assuming that the images are in fact released by the copyright holder under the CC_BY 2.0 license, and not under the CC_BY_NC or CC_BY_SA license, you are free to use the image on a book cover. That the book is erotic makes no difference. You must attribute the cover image to the original creator, as specified in the license, unless the creator has indicated that no attribution should be provided. You must not state or imply that the original creator has in any way endorsed your book or you. Be careful to check that the person releasing the image is in fact the copyright holder. It is not unknown for someone to upload someone else's image and claim to release it under a CC license. Obviously a "license" from someone who had no rights does not give you or anyone any rights. Just as buying stolen goods from a thief does not give you title to them. It is your responsibility to confirm that the person who released the image had the right to do so.
Under 17 USC 106 (3) one of the exclusive rights of a copyright owner is: to distribute copies or phonorecords of the copyrighted work to the public by sale or other transfer of ownership, or by rental, lease, or lending; Distributing an entire book cannot plausibly be considered to be fair use. Nor does the library exception apply. The exception in sec 109 (first sale doctrine) applies only to: the owner of a particular copy or phonorecord lawfully made under this title, or any person authorized by such owner... 17 USC 501 (a) says: (a) Anyone who violates any of the exclusive rights of the copyright owner as provided by sections 106 through 122 or of the author as provided in section 106A(a), or who imports copies or phonorecords into the United States in violation of section 602, is an infringer of the copyright or right of the author, as the case may be. Therefore both Bob and Sue have infringed the copyright, and could in theory be sued for doing so. However I cannot see anything in 17USC which makes receiving an unlawful copy an infringement, or any other crime or tort. It seems to me that Alice has no legal liability, whatever her moral position may be, unless perhaps she could be charged with conspiracy to infringe the copyright, which seems unlikely to me in practice, and perhaps not possible even in theory. If Bob has in fact done this only once, for one book, the chancre of the copyright owner learning of it, or filing suit even if the owner does learn, is perhaps not large. But that would be no defense if the owner chose to sue. Some copyright owners choose to explicitly permit actions similar to that of Bob (where e-books are involved), provided that Bob does not charge a fee, regarding it as good advertising. But that is the copyright owner's choice to make, and most commercial publishers do not take that position. Bob could have legally loaned his copy to Sue, and Sue could have legally passed it on to Alice, without anyone infringing the copyright. Making the copy without permission was infringing, and passing on the unlawful copy was also an act of infringement. Receiving one copy or many does not seem to be a violation, unless it is part of a plan to later distribute unlawful copies. Sue did not make a copy. She distributed an unlawful copy, which is also infringement, as the quoted part of Sec 106 says. While in theory the publisher could have authorized Bob to make the copy, this is not plausible and no reasonable person would believe this to be an authorized copy. So Sue has good reason to believe that the copy is unauthorized. So the distribution is infringement.