And finally …

Contact MG

You can reach me by email. I invite questions, corrections, constructive criticism and complaints (polite ones) with the following caveats:

  1. I do have a day job (surprising isn’t it), I will respond to all polite emails but not necessarily instantly.

  2. I can’t offer detailed engineering advice about specific problems (e.g. why does that valve blow all the fuses when I try to open it), but I will offer pearls of wisdom about less specific software issues.

  3. I don’t know anything about car engines or kettles so please don’t ask.

  4. For the more emotionally tainted, my dogs, Hector and Henry, are Salukis and while it may be off topic I have a soft spot for them and I may be willing to discuss them if pushed.

  5. If your email comes down to “I think your website’s rubbish, I won’t pay for it, but I do want to shout at you for a while about your outrageous shortcomings” then please, there is no need to trouble yourself; you’ve already said everything by not paying.

So if you’re happy with that, you can reach me here:

I’ve included the full details of how I store and manage emails in the privacy and personal data section below:


Thanks to everyone who has paid for this website. Your contributions are appreciated.

Thanks to the dogs: Hector (left) and Henry (right) their advice was invaluable.

Most of the images in the website are my own or of my creation (which probably explains the poor quality).

The fonts used were created by Mr Matthew Butterick and are Equity (serif), Concourse (sans serif) and Triplicate (monospace); I refer to them collectively on the website as the Equity fonts. If you want to use them you can buy them here.

The website uses various third-party software and files, I hope I’ve adequately and correctly made notification of them on the website and in the source code — I do so again here:

File Author(s) Purpose


Nicolas Gallagher
Jonathan Neal
Conditions various html tags so that they are rendered consistently in different browsers


jQuery foundation
(Google hosted library )
jQuery library used to run the jQuery scripts


Caleb Troughton Used to detect when to switch to fixed navigation bar (has many other uses)


Mathias Nater Dynamically hyphenates text within a web page


Google Used to display code fragments within a html page


Lokesh Dhakar Used to overlay images on top of the current page


MathJax Renders AsciiMath, TeX/LaTeX and MathML code as standard mathematical notation
Third-party software running on the website

Normalise, Hyphenator, Lightbox and Waypoints are available under the Github MIT licence (reproduced below) and jQuery, MathJax and Prettify are available under the Apache 2.0 licence (also reproduced below):


The MIT License (MIT)

Copyright © [Authors as listed in the above table]

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. The software is provided "as is", without warranty of any kind, express or implied, including but not limited to the warranties of merchantability, fitness for a particular purpose and non-infringement. In no event shall the authors or copyright holders be liable for any claim, damages or other liability, whether in an action of contract, tort or otherwise, arising from, out of or in connection with the software or the use or other dealings in the software.

Github Massachusetts Institute of Technology (MIT)Licence

The Apache License Version 2.0, January 2004

Copyright © [Authors as listed in the above table]

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at:

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "as is" basis, without warranties or conditions of any kind, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Apache Licence


MG outline

This website is part of the Practical Series of Publications.
It was designed and published in the United Kingdom by Michael Gledhill.

It was first published in April 2017.

The website is printed mainly in the Equity typeface (serif), with headings, tables and annotation in Concourse (sans serif), and code fragments in Triplicate (monospaced).

The fonts have been created by Mr Matthew Butterick and are available here: here.

Hector outline
Henry outline


© 2017 Michael Gledhill. All rights reserved.

The downloadable source code and examples, I make available to all who wish to use them. The text and images within the website may not be publicly reproduced without my written permission. In the unlikely event that you do wish to do so, please send requests to me at:

I have not been compensated to recommend any of the software, websites or products mentioned on these pages or used in the production of this website.

Privacy & cookies

This is a big thing now in Europe and in England: gdpr (General Data Protection Regulation); it means I have to be very careful with any data I collect about people. I also have to explain why I want the data and what I’m going to do with it. So here goes:


The only cookies I use on this site are those needed for google analytics and PayPal I use Goole Analytics to help analyse how visitors use the site. It works by installing cookies on your computer. Cookies are small text files that are used to collect standard internet log data (time of visit, type of browser, operating system &c.) and visitor behaviour information (referring sites, landing page, links to other sites that have been clicked &c.). It collects this data in an anonymous form. Note the deliberate emphasis on anonymous, no personally identifiable information†1 is collected, the type of information collected by Google Analytics is given on their help page under data collected by google analytics.

The anonymous information generated by Google Analytics cookies about your use of this website is transmitted to Google — not to me. This information is processed to compile statistical reports on website activity (for this site only). I use these reports to evaluate the aggregate visitor usage; I do this so that I can optimise the website content, and hopefully, make it better (If I’m being honest, I also like to know how many people visit, it make me feel better if the number goes up).

The PayPal cookie is used for the PayPal checkout process (you have to give PayPal some information if you want to make a donation).

In summary, you can browse this site with complete anonymity.

†1 By default Google Analytics collects the IP address of the website user. This is deemed personally identifiable information under GDPR (i.e. it is not considered to be anonymous), it is possible to stop Google Analytics doing this (by making it anonymise the IP address data, this is done by masking the last three digits of the address, see here for how to activate this option) and this is what I have done on this site.
I am not collecting IP addresses via Google Analytics.

Privacy and personal data

This website does not ask for, nor does it collect, personal data. There is no contact-me form that asks for names, addresses, email details or phone numbers &c. Neither are there any user logons or other such forms of identification.

People can email me if they want to, but that is their choice (I’ve given my email address in a previous section) and I will respond as an individual to any emails I receive.

Where people do email me, I will not pass on any of their details to anyone else (even when they are rude to me). I respond directly to the sender and do not copy, forward or otherwise redistribute their emails with anyone else.

I delete all emails three months after the email conversation is complete (i.e. if you haven’t emailed me for three months I delete all the emails I’ve received from you and any replies I’ve sent to you).

I do not reply to abusive emails (never argue with a stranger on the internet) and these I delete straight away.

Where someone has asked a common or pertinent question, I may store the question itself and my response (these are copied to an offline Word FAQ sheet — what engineers call a technical query sheet), but I do not store any of the questioner’s details (just the question and answer in an anonymous text based format).

I also receive the email addresses and some contact details of those people who make a donation to this website. This information is provided to me by paypal — they tell me who has made the donation.

If the donation is for £5 or more, I keep certain information about that individual in a secure offline database. I store precisely:

  • Name

  • Email address

  • Donation amount

  • Date of the donation

I do this purely for the purpose of sending those people a link to the downloadable pdf version of this website (I make this freely available to all who donate £5 or more).

I keep this information so that I can send a link for each new revision of the pdf when such revisions are issued (typically once a year). I.e. I make the pdfs available in perpetuity.

I do not share this information with anyone.

I do not send marketing or unsolicited emails of any kind (I do not have a mailing list or anything like that).

Anyone wishing to have their details deleted need only ask. You can contact me at the following email address:

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