GenLias has the birth record for Samuel van Gelder:
Geb 08-11-1873 Groningen #1201: Samuel van Gelder g. 08-11-1873 Groningen (Philippus van Gelder, beroep Koopman en Judic Appelboom)
In addition, a Jokos file (number 52600) on this family is at the Amsterdam Municipal Archive. Access is subject to authorization from the Stichting Joods Maatschappelijk Werk.