MI9302 - 1800-1870's Slat Bonnet Pattern. Slat Bonnet: Pattern and illustrated instructions to create a sun or work bonnet worn throughout the 19th century. 19th Century sun/work bonnet with adaptations for late Victorian styles. This Slat Bonnet pattern is a 19th Century sun/work bonnet with adaptations for late Victorian styles. Another every day bonnet, adapted from an original in Lancaster Count Pennsylvania. An everyday or sun bonnet which adjusts at neck and folds flat when not in use. Recommended fabric: 100% cotton in small plaids and prints: blue, green, brown, black, red. Miller's Millinery offers you a Lady's Portfolio of patterns for creating historically accurate 18th and 19th Century head wear. Each pattern is carefully drawn from one or more original items and is illustrated with documentation. Construction techniques used in the step-by-step directions follow original methods.