When the boys left this museum, they went to another and saw a wonderful collection of fossil animals, skeletons, birds, minerals, precious stones, and other natural specimens, but as they were not learned men, they could only walk about and stare, enjoy the little knowledge of natural history they possessed, and wish with all their hearts they had acquired more. Even the skeleton of the mouse puzzled Jacob. What wonder? He was not used to seeing the cat-fearing little creatures running about in their bones--and how could he ever have imagined their necks to be so queer?

Besides the Museum of Natural History, there was Saint Peter's Church to be visited, containing Professor Luzac's memorial, and Boerhaave's monument of white and black marble, with its urn and carved symbols of the four ages of life, and its medallion of Boerhaave, adorned with his favorite motto, Simplex sigillum veri. They also obtained admittance to a tea garden, which in summer was a favorite resort of the citizens and, passing naked oaks and fruit trees, ascended to a high mound which stood in the center. This was the site of a round tower now in ruins, said by some to have been built by Hengist the Anglo-Saxon king, and by others to have been the castle of one of the ancient counts of Holland.