Hello
Does anyone know the patent number of the sidelock Boss (sxs). Some say it was invented by Scott, but I can not find a trace. Dallas Donald said that Robertson is the inventor, but he does not mention the patent number strangely.
thank you
excuse my English!

Which part of the sidelock are you referring to? Most parts will have no patent as they originate at the dawn of time.
The 'spear' interceptor sear was never patented as Boss used it in most of his actions although a similar hook system does appear in his early patent 2833 of 1882.
The usual cocking lever is not covered by any of his patent and is basically a Roger's patent.
The ejectors are usually a variant on any of his 3 patents with Holland 5834 & 11623 of 1887 or 16691 of 1888.
Later he used his own ejector patent 2988 of 1897.

I think Granger is looking at the current Boss SLE as if it were an invention in its entirety, like the Beesley of 1880 or the Anson & Deeley of 1875. As Toby points out, it was not.

yes, like the H & H royal design patented by henry and robertson Holand or Beesley in 1880 etc ...
but the boss side by side (sidelock) , some say it is patented by scott. but I found no trace of the patent!!!
I do not know if I made ​​myself understand

I talked about it, it is a mechanic found on SxS Boss :

Granger,
I would refer you to;" The British Shotgun", Vol,3,Page 275 [Authors,Baker & Crudgington].From the text we learn that two patents, 18,135 of 1895 and 1847 of 1897 were awarded in the names of, John Robertson,trading as,Boss & Co,for a lock safety device.The illustration of this patent is the same/similar to the posted lock pictures.

thank you !
but I do not understand why some especially here in France say that the concept was invented by Scot??