Privacy policy

Principle

This reference is a reading resource. It does not ask a reader to create an account, it does not sell anything, and it does not track a reader across other sites. The information the editorial office holds is therefore limited to what a reader chooses to send, and to the ordinary technical data that any page request produces. That is the whole of the policy in one sentence; the paragraphs below set it out in the detail a formal notice expects.

Information you send

If you use the contact form, the office receives the name, the email address and the message you entered, together with any organization you chose to name. This information is read in order to consider your message, and for no other purpose. It is not sold, not shared with advertisers, and not used to build a profile of you. A correction is retained only for as long as it is needed to prepare the next revision of the sheet it concerns; after that, the correspondence may be discarded at the office's discretion.

Information produced by a page request

When a reader opens a page, the server that delivers it may record basic technical data: the address from which the request came, the page requested, the time, and an indication of the kind of browser used. This data is the normal residue of delivering a page over the network. It is used in aggregate to keep the reference available and to notice faults. It is not used to identify a reader, and it is not combined with information from any other source.

Storage on your device

This reference does not place advertising or analytics storage on your device. Any storage that exists is necessary storage, used so that the pages load and display correctly. The cookie policy explains this in full and is linked from every page. A reader who does not wish even necessary storage to be present may adjust the settings of their own browser, and the reference will continue to be readable.

Legal basis and your choices

Where a law asks for a basis on which information is handled, the reference relies on the reader's agreement, given when a message is sent, and on the legitimate interest of keeping a publication available and correct. A reader may withdraw agreement at any time by writing to the editorial office and asking that their message be removed. Because the office holds so little, such a request is usually simple to satisfy at once.

Retention

Messages are kept for the period during which they may still inform a revision. Short questions are typically answered and then discarded. Corrections that change a figure may be retained a little longer, because they form part of the record of how a sheet reached its present state. No message is kept indefinitely for any commercial reason, since the office has no commercial activity.

Children and third parties

The reference is written for students, engineers and researchers, and it is not directed at children. It contains no form of communication between readers, so no information about one reader is ever visible to another. Where a message names a third party, that name is held only as part of the message and is treated in the same way as the rest of it.

Contact and changes

Requests about this policy, including a request to see or to remove what the office holds about you, may be sent to the address given in the footer. If this policy changes, the change is recorded on this page, and the revision of the reference is advanced in the title block so that a reader can tell one edition from another. The office undertakes to keep the policy short enough to be read and honest enough to be relied upon.