. The microscope and its revelations. extended abetter arrangement ofthe fine adjustment, amechanical stage con-structed on better prin-ciples, and the rotationmade complete and concentric—which it wasnot—this would havebeen, even for our pre-sent requirements, ana d 111 irable instrument. This important firmwere otherwise advised,however; and, insteadPIG. 160. -Ross-Zentmayer model (1878). *! of correcting the error* of the instrument whose they had made, they designed an entirely neir, model in whicha Lister limb was substituted tor the bar movement, Fig. lb0 illus- I|M~ rr fthe instr
. The microscope and its revelations. extended abetter arrangement ofthe fine adjustment, amechanical stage con-structed on better prin-ciples, and the rotationmade complete and concentric—which it wasnot—this would havebeen, even for our pre-sent requirements, ana d 111 irable instrument. This important firmwere otherwise advised,however; and, insteadPIG. 160. -Ross-Zentmayer model (1878). *! of correcting the error* of the instrument whose they had made, they designed an entirely neir, model in whicha Lister limb was substituted tor the bar movement, Fig. lb0 illus- I|M~ rr fthe instrument, from which it will be seen thatthe also was changed for the worse; the base was not sufficiently the hinder part of the font uas too large, so that it times rocked on four points, because the hinder part was too surface, in fact. A true tripod will stand firm on an ible,bu1 this form will not. It is a form liv(|ii«-ntly used by - and is known as the benl daw. Itis a bad be, as it has been, easily thrown over laterally. It. THREE GREAT TYPES OF MICROSCOPE 199 s, however, eventually cast in one piece, which gave it a soliditywhich the former did not possess. The introduction of the Lister limb brought its inevitabletroubles—notably, with the fine adjustment—to which we have fullyreferred under that head. But in the Ross-Zentmayer model, alater form, the body and the coarse adjustment were both carried bythe fine-adjustment lever and screw. This form could not—as it did not—long prevail. Its existencewas ephemeral, and in its place was put a modification of the formdevised by Zeiitmayer, known subsequently as the Ross-Zentmayermodel. This was the Ross-Jackson instrument with a • swingingsub-stage. This instrument is illustrated in fig. 161. It will beseen that the foot is a true tripod, consisting of a triangular basewith two pillars rising from a cross-piece, which carried the trun-nions. Here it may be as well to point out the differences which existbetween
Size: 1230px × 2031px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
