Fine Diatom Microscope Slide Group by Watson
A very fine slide by Watson, it is marked on oval labels in hand-written script, "Group of Diatomaceae, 100 forms, Indian Ocean", and bears the Watson circular label. The entire grouping is shown in the photo with darkfield illumination. A close-up, color-enhanced photo is behind. The slide contains 100 different diatoms, meticulously laid out in a circular pattern. Diatom slides were quite popular in England toward the end of the 19th century, and were often used to test the resolving power of the optics. Some manufactures made test slides using the diatom Pleurosigma angulatum. Slide groups, like the one featured here, were done to show the variety of forms available in a particular locale. With its immense variety, careful spacing, and fine detail, the 100 different forms featured here are like having an entire slide box of diatoms on one slide!