's-Gravenhage (or 's Hage or Den Haag) is the Dutch name for The Hague and is a town on the sea side of The Netherlands. 's-Gravenhage means the Count's hedge. Latin: Haga Comitis.

Around 1900 the Dutch PTT asked an engineer from The Hague, Mr. C. C. van der Valk to construct a machine with a postmark that could burn an impression in the stamps on postcard and on the envelope without damaging the content of the letter¹. In one year C. C. van der Valk had made a useful machine that worked with a red heat postmark. As electricity was not commen at the post offices at that time C. C. van der Valk used a kerosen flame to heat the postmark. The kerosen reservoir was placed above and away form the machine and the flame was fed by the kerosene through a thin pipe.

On 3 August 1901 the brandstempel-machine Vulcanus was installed in the 's-Gravenhage post office² - see photo - and the first known oblitartion is from 5 August 1901³ from the day when the machine was tested. The machine was taken in regular use from 6th August 1901⁴.

From the photo you can see that the machine was operated by a pedal and a skilled postman could obliterate as many as 240 letters/postcards per minute and a not trained person could obliterate about 100 per minute. The machine used only one litre of kerosene every five and a half hours and the price was 1.5 cent per hour for the kerosene⁵.

Two postmarks were in use in the trial period for the machine:

Cllick here to see a close up of the brandstempel from this postcard.

According to Erik Jensen from the Danish Post- & Telemuseum C. C. van der Valk offered his Vulcanus to the Danish General Post Office on 30 April 1901. As Erik Jensen write in his article: The machine was hot news at that time but to the pleasure for the future stamp collectors, the Danish GPO did not accept Mr. van der Valk's offer! ⁷

References:
1. Brandstempel "Vulcanus" van 's-Gravenhage by E. Haak. POST-FRYS; Newsletter from
    Vereeniging van Postzegelverzamelaars Friesland, September 1985, page 3-5.
2. Het Brandstempel in Newsletter of the Post Zegel Verzamelaars Noordwijk's newsletter, December 1997, page 17 and 18.
3. Brandstempels by Arie Bakker. Newsletter of the Post Zegel Verzamelaars Breda, May 1998, page 8 and 9.
4. Nederlandsch Maandblad voor Philatelie, no. 6, 16 June 1928, page 108.
5. O.M. Vellinga: De poststempels van Nederland 1676-1915. Nederl. Bond van Ver. van Postverz. 1932, page 126-127 and plate book, page 13.
6. Rate book.
7. Stemplingsmaskiner og Maskinstempler by Erik Jensen. Nordisk Filatelistisk Tidsskrift no. 5/6 1982, page 141.

Acknowledgements:
Thanks are due to Rob Vlaardingerbroek, 's-Gravenhage, for valuable help with this article.