An antique brass microscope by Hartnack & Prazmowski of Paris, their details are inscribed on the draw tube. Hartnack & Prazmowski were a Parisian optical business founded by Georg Oberhaeuser, who popularised Martin’s drum microscope pattern and developed the horseshoe-footed continental stand, as we see in this example. Oberhaeuser began his business in 1830, in 1854 he formed a partnership with his assistant Hartnack  and retired shortly afterwards in 1854. The business operated as “Oberhaeuser and Hartnack” until 1859, when Hartnack became the sole owner and the firm became simply “Hartnack”. Hartnack left France in 1870, at the outbreak of the Franco-Prussian War, and went to establish a business in Potsdam, near Berlin, known as Hartnack. 
 
The Microscope stands 28.5cm (11.22") high before being extended, 33.5cm (13.19") after being extended.