Date: 1880 |
The Professional was McAllister's largest model. It was priced at $73.50 with two eyepieces, two objectives and a case in 1879. The most unusual feature of McAllister microscopes is the coarse focusing mechanism. Rather than using a rack and pinion, he used a fusee chain, similar to a miniature bicycle chain. Chain focusing was first introduced by Smith and Beck in the Universal model, but was not used in their other models. The captive gliding glass stage is also an unusual feature. more...