...; transferred from the Ministerie van Marine (Department of the Navy), The Hague, to the museum, 1883

Object number: NG-MC-79

Patent model of a ladder for threefold usage: it can be used as a single ladder, as an extended ladder or as a shore ladder.¹¹J.M. Obreen, Catalogus der verzameling modellen van het Departement van Marine, The Hague 1858, no. 79. The extending part, which is to be lifted by hand, has a small wheel at the top of each leg. Two ratchets prevent this part from sliding back. The top of the lower part is fitted with two hinges to which the extending part can be attached; and when the brace at the bottom is subsequently removed, the whole is converted into a shore ladder.

Petrus van der Loo (1806-1864) obtained a five-year patent for his improvements to ladders²²J.M. Obreen, Catalogus der verzameling modellen van het Departement van Marine, The Hague 1858, no. 81. in 1850. His model was shown at the Exposition Universelle of 1855 in Paris.³³Expositions des produits de l’industrie de toutes les nations, 1855. Catalogue officiel, Paris (1855), p. 381.

Expositions des produits de l’industrie de toutes les nations, 1855. Catalogue officiel, Paris [1855], p. 381; J.M. Obreen, Catalogus der verzameling modellen van het Departement van Marine, The Hague 1858, nos. 76-81; G. Doorman, Het Nederlandsch octrooiwezen en de techniek der 19de eeuw, The Hague 1947, no. 1845, p. 305; A.A. Lemmers, Techniek op schaal. Modellen en het technologiebeleid van de Marine 1725-1885, Amsterdam 1996, pp. 260, 355

J. van der Vliet, 2016, 'Petrus van der Loo, Model of a Ladder, The Hague, c. 1850', in J. van der Vliet and A. Lemmers (eds.), Navy Models in the Rijksmuseum, online coll. cat. Amsterdam: https://data.rijksmuseum.nl/20053228