Only Dietz globes are reasonably datable, except for the Ham Nu-Style and other short globes. No doubt Simmons carried tubular lanterns in their catalog from the 1870's until they were bought by Shapleigh in 1940. All short globes are post-1912. All globes can be roughly dated by their manganese content. Manganese was used as a clear glass clarifier until 1915 and causes the glass to turn purple when subjected to prolonged sunlight. The manganese can also be detected by black(UV)light. Take your globe into the dark and view it under black light. If it glows a greenish-yellow it is pre-1915.