Carl Zeiss was born in 1816 and in 1846 he established his first business in Jena. The following year he was already selling his own models. In 1866, 200 employees worked with him and he sold the 1,000th copy. This year he contacts Ernst Abbe, who develops great innovations and new techniques for optics and becomes his partner in 1875. In 1888 Zeiss dies, but his company It continues directed by Abbe manufacturing magnificent microscopes, which reach their maximum prestige around 1900, at which time the company has more than 1000 employees.
Excellent and elegant brass microscope made in 1895 based on the IV model, but adapted to the innovations provided by Abbe, which is why it is known as IVa. It has the number 27080 and is in a housed condition in its original box. It has 4 objectives, A, C, D and 1/12 oil immersion, as well as 4 eyepieces, 1, 2, 3 and 4, allowing a range of magnifications from 37X to 925X. It has a lighting system under the platform designed by Abbe, which concentrates the light reflected by the mirror in a cone of rays with a large opening, projecting them on the object to be viewed. It also has a mechanical platform for the micrometric movement of the preparations.
References: "Microscopes and Microscopical Instruments", C. Zeiss 1889
H. Moe, "The Story of the Microscopes", pag 220-236