Back Button




MODEL: 'VII' or 'Grand Model'



SIGNED: 'E. Hartnack & Co., Paris & Potsdam'on the optical tube



Please Click On Any Picture for a Larger Version

sigDESCRIPTION: This is a large and very heavy continental microscope by Edmund Hartnack. The microscope alone, without optics weighs about 10 lb or 4.5 kg; the microscope and accessories in the original box weigh 23.5 lb or about 10.7 kg. It comes with its original case with serial number embossed into front inside edge of the case. The inside of the top of the case is lined with a cushion covered with violet-colored silk. As is the case for many other examples of this model, at the site of contact with the microscope stage, and the base of the bullseye, the liner is torn. The microscope is signed on the main optical tube: 'E Hartnack & Co., Paris & Potsdam'. It arises from the heavily weighted horseshoe-foot on a double-upright with an inclination joint. The foot is filled with some sort of concrete, as is the bottom of the bullseye condenser support. The stage is covered with hard rubber. The stage and optical tube can rotate as a unit. There are two steel stage clips.

Understage and substage Under the stage is a dovetail slot to accept a slide-in understage plate carrying a ring to accept substage apparatus. This slides in from left to right when one faces the front of the microscope. The ring accepts two different substage condensers. Both of these substage accessories are illuminated by a fully adjustable plano-concave mirror which has an articulated arm and gimbal; the gimbal is attached to an arm which can slide up and down the slotted tailpiece. There is another completely separate assembly which has a lensed condenser system with a mirror permanently mounted on a gimbal at the lower end(see below). The last arrangement is designed to be used with both the understage plate and the separate mirror removed.

Coarse focus is by straight rack and pinion, fine is by vertical continental screw, controlled from the top of the limb. There is a nickel plated draw-tube. This microscope has been adapted to accept any of the outside-threaded Seibert objectives now with the microscope. The nosepiece changer can accept any five of them. Four adapters are also provided so the nosepiece changer can accept objectives of a different type, with internal instead of external threads. There is also a single adapter to allow the same kind of objective to be used singly without the quintuple nosepiece. There are seven Seibert objectives, two with correction collars, and one is an oil immersion objective. There are seven eyepieces, two of which are corrected types. An Oberhauser type of Camera lucida, complete with two protective caps is also supplied as is a very heavy, large diameter benchtop bullseye condenser. The bottom of the microscope, the bullseye support, and the outer case are all covered with tan leather on their bottoms, to protect the surface of the table they would sit on. A lacquered brass name-plate is screwed onto the top of the case and is engraved in script with the prior owner's name: 'Carl Ewald'


hartnack eyepiecesThere are seven eyepieces currently in this outfit. They are numbers 1,2,3,4,5, as well as a 'Periskopisch I' and a 'Periskopisch III' The latter two are top-hat types.

hartnack eyepiecesThe microscope includes seven objectives by Seibert. Two of these have correction collars and three are oil immersion objectives. These include a 1/16 homog imm, a 1/12 homog imm, a No VI with correction collar, a No VII immers with correction collar, a No V, a No IV, and a No II. The three highest power objectives came in their own brass cans, while the other four came in a amall leather-covered wooden case which also contans an etched glass micrometer in a small metal slide mount.

There are three different substage light-regulating arrangements provided with this microscope. The first two fit into a ring at the bottom of a plate which slides into brackets under the stage. The other one replaces the mirror assembly on the tailpiece and has its own mirror. The slide in plate is removed when this configuration is used.

pinhole cond This is the simplest of the substage fittings. It is a barrel accepting one of three different plugs, each with a different diameter aperture, to regulate the size of the light beam projecting up through the slide. The distance to the slide is adjusted simply by pushing or pulling the apparatus into, or out of, the understage ring.

This second apparatus is a lensed condenser system. It has a slot on its bottom to accept one of four inserts but also has a wheel of apertures under that. This wheel is on a push-on fitting and is easily removed. The wheel includes four apertures and a dark ground stop. The inserts include three with apertures but also a blue glass filter that can be used in combination with the wheel. The distance of this lensed condenser to the slide is adjusted by push-pull, just like the plain aperture device described in the previous entry.

The third condenser system differs from the other two in that it is a single fitting with both condenser and mirror attached. When this is to be used, the substage plate with ring is removed. This condenser system is then installed in the slot of the substage tailpiece in place of the other mirror. The entire unit can move up or down the tailpiece, just like the main mirror would have. The mirror of this unit is gimbaled but its distance from the condenser cannot be varied-this distance is fixed; as the condenser is raised or lowered, so is its mirror. This condenser has a swing-out ring to accept inserts, either round, aperture-limiting stops for dark-ground work, or one of four different density blue glass filters. The ring containing these inserts can be moved in or out of the optical path via a rack and pinion mechanism to allow oblique lighting.

camera lucida on scopeThe instrument includes an Oberhauser-type camera lucida.

Hartnack Bullseye Bench CondenserThe microscope comes with a bench-type bullseye condenser with a very heavy weighted base. It is on a fitting that telescopes out of the tube attached to the base and a knurled knob adjusts its ankle.

Hartnack quintuple objective changerHartnack quintuple objective changerThe microscope came equipped with a quintuple objective changer. This is capable of holding 5 of the 7 included Seibert objectives at any one time. Five adapters are also provided for use with other objectives.

adapterThis adapter allows attachment of a single objective to the nosepiece and is in two parts allowing different types of objectives to be attached, much like the quintuple nosepiece above.

Hartnack microscope caseThe microscope came in its original case with Ewald's nameplate on the top. It has two locks and the original key. The case has hidden dovetail construction. The inner lid is lined with a cushion covered in thin purple cloth. The bottom of the case, and also the bullseye stand are covered in leather.

The case is well built but this microscope and accessories are very heavy which means that rough handling of the cased instrument was likely to result in severe damage to the case. Repairs have been made to the case, with little of these repairs easily visible except for some areas inside the case when the microscope and other equipment are removed from it. Some repaired cracks are visible on the outside panels.

The case contains a removeable fixture that holds all the eyepieces, as well as two other sliding-lid removable wooden boxes to house accessories.

boxesboxes Some of the accessories such as the stops and adapters are are now stored in little cardboard boxes. One is by Rud. Seibert, one by Seibert & Krafft, and one signed inside the lid by Michael Goldschmidt Sonne. These boxes were originally meant to house things such as indigo carmine and cover slips.

This model was produced for many years. It is likely it was produced from the 1870's through 1891 when Hartnack died. I know of catalog entries from as early as 1872 and as late as 1885 which offered this model, and there may be others, both earlier and later.

HartnackEdmund Hartnack was born in 1826. After working for various instrument makers, he joined Oberhauser in the 1850's. He married Oberhauser's niece, and eventually succeeded Oberhauser in 1864, the same year he was joined by Adam Prazmowksi. Prazmowski remained in charge of the Parisian branch when Hartnack left to go back to Germany in 1870. By 1872 Hartnack started to sell instruments in Potsdam signed like the one on this page, 'E Hartnack & Co., Paris & Potsdam'. In 1878 Prazmowski became the sole owner of the Parisian branch. Starting at around that time, Hartnack's reference to Paris in the signature was no longer used. When Prazmowski died in 1885, his business was taken over by his employees Bezu and Hausser, who sold the business to Nachet in 1896. Catalogs of Bezu and Hausser list and illustrate Hartnack microscopes.

By referring to one bill of sale, we know that serial number 12498 can be traced to sale in September of 1873. The microscope shown here, with serial 19455 must be later, but how much later is not clear. Hartnack died in 1891, but who ran the business from 1891 until it was incorporated into Nachet by 1898 is unclear. A catalog from 1902 still refers to the products as 'Microscopes of E. Hartnack', though he died in 1891 and Nachet owned the company by 1898. Serial numbers of Hartnack microscopes are known to at least number 22825. Taking all of this into account, the serial number of my microscope, 19455 is somewhere after 1873 and very likely before 1878, since the reference to Paris was no longer used.

Seibert, successors to Gundlach in Germany, were contemporaries to Hartnack. If this microscope was retailed by someone other than Hartnack himself, it would be easy to see how the Seibert objectives were included rather than Hartnack's. For one thing, the wholesale price of Seibert objectives might have been lower than Hartnack's, and they would be just as easy to obtain. Seibert and Krafft became Seibert about 1884.

ewaldAs noted above, the former owner's name is engraved on a plate(right), screwed onto the top of the case. ewald Dr Carl Ewald (1845-1915) was a famous German gastroenterologist, known for his work on digestion in the stomach. He invented the technique of gastric intubation via a tube of relatively large diameter. This tube is partly 'swallowed' by the subject. He invented this tube to allow stomach contents to be withdrawn for analysis, which is how he studied ordinary gastric digestion. He also used it to study pathological processes of digestion. Today the Ewald tube is still occasionally used to empty the stomach, but mostly for the purpose of removing pills and capsules soon after attempted suicide. This is often referred to in layman's terms as 'pumping the stomach'. Ewald published some famous books including Lectures on the Diseases of the Digestive Organs (1891) and Diseases of the Stomach (1892) which were both translated into English, the latter through three editions. In his book about the stomach, Ewald discusses the use of microscopical analysis of stomach contents in the diagnosis of stomach diseases. The microscope shown on this web page was likely the microscope he used for the microscopical studies of the stomach contents that he himself examined. Noting that there are three different condenser arrangements, two of these may have been later additions by Ewald to aid in his research using the higher power objectives.