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Robert K. Wismer Collection of Chemical Museum Slides
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Held at: Science History Institute Archives [Contact Us]315 Chestnut Street, Philadelphia, PA 19106
This is a finding aid. It is a description of archival material held at the Science History Institute Archives. Unless otherwise noted, the materials described below are physically available in their reading room, and not digitally available through the web.
Overview and metadata sections
Dr. Robert K. Wismer received his B.S. in Chemistry from Haverford College in 1967 and his Ph.D. in Physical Chemistry from Iowa State University in 1972. He began teaching as a professor in the Chemistry Department of Millersville University in 1976, where he taught introductory chemistry, physical chemistry, history of chemistry, and chemistry for non-science majors. Previously, Dr. Wismer taught chemistry and computer science at Denison University, Luther College, Des Moines Area Community College, and Iowa State University. At Millersville, he was member and chair of the Undergraduate Course and Program Review Committee, the General Education Review Committee, and the Curriculum Committee of the School of Science and Mathematics, and was also involved with the Southeastern Pennsylvania Section of ACS. Dr. Wismer published multiple editions of a study guide, laboratory manual, solutions manual, and instructor's guides for general chemistry, and a qualitative analysis textbook. In the spring of 2000, Dr. Wismer went on sabbatical to pursue a project that involved photographing scientists, apparatus, and laboratories that were important in the history of chemistry at European museums and institutions. The goal was to use these to teach, as Dr. Wismer believed that photographs help students to better understand and connect with the history of science on a more human level, and they provide context by showing the circumstances under which chemical investigations and scientific discoveries were made.
This collection contains a selection of Dr. Wismer's photographs from his sabbatical project, in the form of 35mm transparencies, taken in the following institutions: Hunterian Museum of the University of Glasgow, Scotland; Museum of Science and Industry, Manchester, England; Cavendish Laboratory, Cambridge, England; Whipple Museum, Cambridge, England; Royal Institution, London, England; Teyler's Museum, Haarlem, Netherlands; Museum Boerhaave, Leiden, Netherlands; Museum of the History of Sciences, Ghent University, Ghent, Belgium; Technisches Museum Wien, Vienna, Austria; Museum of the History of Science, Geneva, Switzerland; Pharmazie-Historisches Museum, Basel, Switzerland; University of Heidelberg, Heidelberg, Germany; and Liebig Museum, Giessen, Germany. The slides depict laboratories, scientific apparatus, instruments, glassware, molecular and atomic models, and other objects used and/or created by various chemists throughout history, notably James Joule, John Dalton, Michael Faraday, August Kekulé von Stradonitz, Justus von Liebig, and Robert Bunsen. The collection does not include photographs of the chemists themselves. The objects depicted in the slides date from the late seventeenth century through the early twentieth century, and pertain to a variety of chemistry-related subjects, including electricity, electrochemistry, heat, combustion, optics, and gases. Notably, there are several examples of voltaic piles, calorimeters, and both steam and atmospheric engines. The slides are arranged by institution, in the order Dr. Wismer took them, and are labeled with the title, slide number, and relevant institution Additionally, Dr. Wismer provided contextual descriptions for many of the objects; these descriptions are transcribed in the inventory that appears at the end of this finding aid.
Collected by donor during his 2000 sabbatical and used while teaching about the history of science.
Gift of Dr. Robert K. Wismer, 2000.
Processed by Robert K. Wismer in 2006. Object identification numbers were assigned to individual items.
Organization
- Cavendish Laboratory (Cambridge, England)
- Hunterian Museum (University of Glasgow)
- Liebig Museum
- Musée d'histoire des sciences de Genève
- Museum Boerhaave
- Museum of Science and Industry in Manchester
- Museum Wetenschap en Techniek (Ghent, Belgium)
- Pharmazie-Historisches Museum Basel
- Royal Institution of Great Britain
- Technisches Museum für Industrie und Gewerbe in Wien
- Teylers Museum
- Universität Heidelberg
- Whipple Museum of the History of Science
Subject
- Publisher
- Science History Institute Archives
- Finding Aid Author
- Finding aid created by Jennifer Nieling and encoded into EAD by Melanie Grear. Edited by Alex Asal in 2023.
- Finding Aid Date
- 2017
- Access Restrictions
-
There are no access restrictions on the materials for research purposes and the collection is open to the public.
- Use Restrictions
-
To obtain reproductions and copyright information, contact: reproductions@sciencehistory.org
Collection Inventory
Hunterian Museum of the University of Glasgow, Scotland. Portion of a voltaic pile. Made in 1860 by James Joule. The zinc disk is spot welded to the copper disk at the center. Joule sent the completed voltaic pile back to William Thomson as an example of what he (Joule) could do. Held by Michael Jewkes, museum curator.
Physical Description1 Photographic Prints
Hunterian Museum of the University of Glasgow, Scotland. Thermometers belonging to William Thomson, Lord Kelvin. These were among the first thermometers with a uniform capillary bore.
Physical Description1 Photographic Slides
Hunterian Museum of the University of Glasgow, Scotland. James Joule's electric motor.
Physical Description1 Photographic Slides
Hunterian Museum of the University of Glasgow, Scotland. Calorimeter belonging to James Joule. Inside is a paddle-wheel arrangement that enables one to determine the mechanical equivalence of heat.
Physical Description1 Photographic Slides
Hunterian Museum of the University of Glasgow, Scotland. Interior of James Joule's calorimeter. With this calorimeter and others of this type, Joule determined the mechanical equivalent of heat.
Physical Description1 Photographic Slides
Hunterian Museum of the University of Glasgow, Scotland. This model of a Newcomen atmospheric engine was fixed by James Watt, when working as an instrument repairer. As a result of fixing this model, Watt realized that Newcomen engines use steam inefficiently. This led to Watt developing the steam engine, in which expanding steam pushes a piston in a cylinder. In a Newcomen engine, the condensation of steam pulls a piston. In addition, steam is condensed in a Newcomen engine by spraying cold water into the cylinder.
Physical Description1 Photographic Slides
Hunterian Museum of the University of Glasgow, Scotland. Gear train cleaned by James Watt: "To cleaning a machine to show forces of wheels and pinions. 1/-" (1 shilling, 0 pence).
Physical Description1 Photographic Slides
Museum of Science and Industry, Manchester, England. Model Watt steam engine, used by John Dalton in teaching.
Physical Description1 Photographic Slides
Museum of Science and Industry, Manchester, England. Thinking cap worn by John Dalton, on loan from Dalton Hall, Manchester University.
Physical Description1 Photographic Slides
Museum of Science and Industry, Manchester, England. Balance and some chemicals of Edward Frankland. While at Manchester University, then Owens College, Frankland developed the concept of the chemical bond, c. 1850
Physical Description1 Photographic Slides
Museum of Science and Industry, Manchester, England. Thermometer and marking microscope of James Joule. Made by Dancer, a prominent instrument maker of the mid-1800s in England.
Physical Description1 Photographic Slides
Museum of Science and Industry, Manchester, England. James Joule's calorimeter, containing a paddlewheel. Used to determine the mechanical equivalent of heat.
Physical Description1 Photographic Slides
Museum of Science and Industry, Manchester, England. John Dalton's atomic models. In the words of a critic of the atomic theory: "Atoms are round bits of wood invented by Mr. Dalton."
Cavendish Laboratory, Cambridge, England. Three-dimensional plot of entropy, energy, and volume, constructed by James Maxwell.
Cavendish Laboratory, Cambridge, England. Leiden jar with movable coatings, to demonstrate that nearly all of the charge carried by the jar is on the glass surface between the coatings.
Cavendish Laboratory, Cambridge, England. Gas discharge tube, with which J. J. Thomson discovered and characterized the electron, and determined the charge to mass ratio.
Cavendish Laboratory, Cambridge, England. Chamber in which James Chadwick discovered and characterized the neutron.
Cavendish Laboratory, Cambridge, England. Very early X-ray tube, captioned 1890-1900. (Roentgen discovered X-rays in November 1895.)
Whipple Museum, Cambridge, England. Portable apothecary's balance. Often the center of such a balance is suspended from an overhead hook or simply from the user's hand.
Whipple Museum, Cambridge, England. Blowpipe kit. Blowpipe analysis is used to quickly identify materials, based on their behavior in intense heat, and the glasses that they form. The technique is rarely used at present, except by amateur field mineralogists.
Whipple Museum, Cambridge, England. 19th century brass blowpipe for chemical analysis, with alcohol burner. To use, the sample is placed on the marble(?) block. The user blows through the flared end of the blowpipe, directing air through the alcohol flame and on to the sample. Intensely heating the sample produces colors that aid in its identification. In addition, borax or soda ash (sodium carbonate) can be mixed with the sample before heating. The color of the resulting glass provides identification clues.
Royal Institution, London, England. A voltaic pile given by Alessandro Volta, its discoverer, to Michael Faraday. A voltaic pile consists of alternating disks of dissimilar metals, with an electrically conducting medium--typically brine-soaked blotting paper--between pairs of disks. A voltaic pile was the first device to produce electricity from a chemical change. Previously only static electricity generators were used.
Royal Institution, London, England. Vessels used by Michael Faraday in discovering the first and second laws of electrolysis, linking the mass of substance deposited during electrolysis and the quantity of electric charge employed.
Royal Institution, London, England. Apparatus used by Michael Faraday for the electrolysis of water. Each of the product gases--hydrogen and oxygen--collect in one of the slightly slanted cylinders, enabling one to measure the amount of each gas evolved.
Royal Institution, London, England. Each sealed bulb contains a different gas. Faraday investigated the effect of a magnetic field on each gas. A diamagnetic substance is one that is repelled by a magnetic field.
Royal Institution, London, England. Michael Faraday's "electric egg." Faraday passed electricity through gases enclosed in the "egg" and produced different colors, the predecessor of discharge tube experiments.
Royal Institution, London, England. Sample of benzene, isolated by Michael Faraday from the illuminating gas mains in London.
Royal Institution, London, England. Apparatus used by Michael Faraday to liquefy gases, including natural gas (methane).
Royal Institution, London, England. Reconstruction of Michael Faraday's laboratory.
Royal Institution, London, England. Faraday's watch, given to him by Humphry Davy, who had hired Faraday to work at the Royal Institution. In addition, two small magnets.
Royal Institution, London, England. Interior of Faraday Museum.
Teyler's Museum, Haarlem, Netherlands. Oil combustion chamber (1791 in the style of Lavoisier). Large glass flask contains an Argand burner of glass and brass. Right-angled brass tube admits oxygen; free brass tube removes combustion products; brass tube into cylinder admits oil.
Teyler's Museum, Haarlem, Netherlands. Voltaic pile, c. 1800. Alternating zinc and copper plates.
Museum Boerhaave, Leiden, Netherlands. Single-barrel vacuum pump, in the manner of Robert Boyle, c. 1665.
Museum Boerhaave, Leiden, Netherlands. Set of Leiden flasks, made by John Cuthbertdon, 1775-1800.
Museum Boerhaave, Leiden, Netherlands. Spectroscope by J. Duboscq, Paris c.1870. Light that was produced by placing a sample in a Bunsen burner flame, is refracted by a prism (on the center table) and observed through a telescope.
Museum Boerhaave, Leiden, Netherlands. Before modern separatory funnels, separatory flasks such as these were used to separate liquids of different density. The more dense liquid, on the bottom, was poured off through the side arm.
Museum Boerhaave, Leiden, Netherlands. Rotating wire motor, in the manner of Faraday 1825-50. Mercury is placed in the shallow dish, at the center of which is fixed a permanent magnet. Electric current, such as from a voltaic pile, is passed through the wire and into the mercury. The moving current creates a magnetic field around the wire. Its interaction with the permanent magnet causes the wire to rotate. This is generally accepted as the predecessor of electric motors.
Museum Boerhaave, Leiden, Netherlands. Comparative colorimeter, c. 1885, Hamburg, A. Kruss. In this type of colorimeter, a solution of known concentration is placed in the left-hand compartment; the unknown solution in the right. The optics (at the top) produce a split circle image. As the flat-bottom, closed-end, glass cylinder is lowered into the left-hand sample compartment, light passes through a successively shorter length of solution. Eventually, the color intensity of the two half-circles match, at which point the product of concentration (C) times path length (L) is equal for each solution, standard (s) and unknown (u), that is, C(u) L(u) = C(s) L(s). As both path lengths are known as well as the concentration of the standard, the concentration of the unknown, C(u), can be calculated.
Museum Boerhaave, Leiden, Netherlands. Jacobus Henricus van't Hoff's cardboard models of malic acid, succinic acid, and tartaric acid. These models enabled van't Hoff to demonstrate the asymmetry that exists around a tetrahedral center in certain molecules.
Museum Boerhaave, Leiden, Netherlands. Jacobus Henricus van't Hoff's cardboard models of malic, succinic, and tartaric acids. With these models he demonstrated the asymmetry that exists around a tetrahedral center in certain molecules.
Museum Boerhaave, Leiden, Netherlands. Johann Diderik van der Waals (1873) PVT surface zaal bergran Zeist (1898). This plaster model depicts the pressure-volume-temperature behavior of a gas that is described by the van der Waals equation.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. Complete set of weights in quartz for a balance, dated 1887.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. Benzene ring modeled with August Kekulé von Stradonitz's sausages. Original dates from the 1800s; copy was made in the 1960s.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. 1,3,5-trimethyl benzene molecular model made with tetrahedral centers.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. The kaliapparat was part of Justus von Liebig's method of combustion analysis. This apparatus was filled with KOH(aq). Carbon dioxide produced by combustion was absorbed in the KOH(aq), resulting in an increase in weight.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. Alembics were used for distillation through the end of the 19th century. The flask was heated and the vapors condensed on the inside of the cooler head at the top. The condensate then ran out the spout.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. August Kekulé von Stradonitz's laboratory bench, with distillation apparatus, including a Liebig condenser.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. August Kekulé von Stradonitz's laboratory bench, with a Liebig condenser.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. Paper maché bottle for HF(aq). HF(aq) attacks glass.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. Florentine separatory flask was used to separate liquids of different densities before the advent of separatory funnels. The more dense liquid stays at the bottom and can be poured off the spout.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. An alembic was used for distillation until the end of the 19th century. Vapors of the liquid heated in the flask at the bottom condensed on the inside of the cooler head and were drawn off at the spout.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. August Kekulé von Stradonitz's analytical balance, brought with him from Germany.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. August Kekulé von Stradonitz's analytical balance, made for him in Belgium. (University of Ghent was established in 1817).
Museum of the History of Sciences, Ghent University, Ghent, Belgium. Balance designed by Pierre Curie, who invented the damper. This is an aperiodic precision balance. Society Central de Produits Chemies.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. August Kekulé von Stradonitz's blackboard.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. Caption reads: "Kwikpump volgens [according to] D.H. Geissler, c. 1900 Franz Moeller, Dr. G's Nachfolger Bonn a/Rh." Crank raises and lowers the outside reservoir. Proper opening and closing of the valves produces a vacuum within the apparatus, which becomes more rarefied with each cycle. In 1857 Heinrich Geissler invented the tubes that bear his name. Each contained a nearvacuum and was used to demonstrate and investigate the effect of electricity on the material left in the tube.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. Transparent, dark brown Bakelite buret. First pieces handmade by Leo Baekeland. This buret was probably among a group that was sent to the American Chemical Society. [Leo Baekeland's father-in-law, Schwartz, was Kekule's successor at Ghent.]
Museum of the History of Sciences, Ghent University, Ghent Belgium. Invented in 1870, Duboscq colorimeters were sold through the mid-1900s. One sample container holds solution of known concentration (Ck); the other holds solution of the same solute of unknown concentration (Cu). The pathlength for the known solution (Lk) is fixed; that for the unknown solution (Lu) is adjusted until the intensity of the (colored) light appears the same when viewed through the eyepiece at the top. The product of pathlength and concentration is constant: Lk X Ck = Lu X Cu, allowing one to determine the concentration of the unknown solution.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. Wooden test tube holders.
Museum of the History of Sciences, Ghent University, Ghent, Belgium. Laboratory chemicals in original packaging, c. 1900.
Museum of Science and Industry, Manchester, England. Model steam engine used by John Dalton for teaching. Museum curator noted repairs and speculated that they had been made "after the war" to repair "bomb damage."
Museum of Science and Industry, Manchester, England. Model steam engine used by John Dalton for teaching. Museum curator noted repairs and speculated that they had been made "after the war" to repair "bomb damage."
Museum of Science and Industry, Manchester, England. Walking-stick barometer owned by John Dalton, who recorded his observations of the weather every day for 57 years, including the day he died. A facing half-stick covers the barometer and thermometer to protect them; it is held in place by the screw-on handle of the walking stick.
Museum of Science and Industry, Manchester, England. Walking-stick barometer owned by John Dalton, who recorded his observations of the weather every day for 57 years, including the day he died. A facing half-stick covers the barometer and thermometer to protect them; it is held in place by the screw-on handle of the walking stick.
Museum of Science and Industry, Manchester, England. Walking-stick barometer owned by John Dalton, who recorded his observations of the weather every day for 57 years, including the day he died. A facing half-stick covers the barometer and thermometer to protect them; it is held in place by the screw-on handle of the walking stick.
Museum of Science and Industry, Manchester, England. Eudiometer owned by John Dalton. This is of the design of Henry Cavendish and is used to test the "goodness" of air, its proportion of oxygen. The air to be tested is collected in the eudiometer over water, with the top end of the eudiometer capped (and fitted with electrodes) and the bottom end immersed in water. A small quantity of hydrogen gas is added to the trapped air, and ignited with a spark through the electrodes. The amount by which the water rises in the tube indicates the "goodness" of the trapped air.
Museum of Science and Industry, Manchester, England. Leiden jar used by Dalton. A Leiden jar is an elementary form of a capacitor, that is used to store static electricity, generated by a friction device. The glass of this jar is slightly green and the metal coating is flaking, leading one to assume that Dalton was a man of modest means.
Museum of Science and Industry, Manchester, England. Flat-bottom flask of William Henry, a close friend of John Dalton.
Museum of Science and Industry, Manchester, England. Dalton's spectacles. As per his wish, Dalton's eyes were preserved after his death, and are in the collection at the Museum of Science and Industry at Manchester, but not available for viewing by the public.
Technisches Museum Wien, Vienna, Austria. Gasometer nach Lavoisier, made by J. N. Fortin, Paris, 1790. With a device similar to this, Lavoisier demonstrated that hydrogen and oxygen react to form water in the ratio of two volumes of hydrogen to one volume of oxygen. The obvious cost of devices such as these lead many to believe that chemical investigations could be performed only by the wealthy.
Technisches Museum Wien, Vienna, Austria. Model of carbon atom according to the atomic theory of Niels Bohr. The model shows the orbits of electrons predicted by Bohr's theory.
Museum of the History of Science, Geneva, Switzerland. Angle barometer, which makes a small rise or fall in the mercury level easier to determine.
Museum of the History of Science, Geneva, Switzerland. Angle barometer, which makes a small rise or fall in the mercury level easier to determine.
Museum of the History of Science, Geneva, Switzerland. Differential thermometer, by Deleui(?), c. early 1800s, type of (Sir) John Leslie and also of Count Rumford (Benjamin Thompson).
Museum of the History of Science, Geneva, Switzerland. Reproduction of a type IV thermometer of the Accademia del Cimento of Florence Italy of the 17th century. (The somewhat popular Galileo floating bulbs in a cylinder thermometer is type V.)
Museum of the History of Science, Geneva, Switzerland. Zinc/copper voltaic pile with glass rods for insulation. The repeated sequence is: zinc disk, copper disk, brine-soaked cloth disk.
Museum of the History of Science, Geneva, Switzerland. Magdeburg hemispheres, demonstration set. The hemispheres are mated and connected to a vacuum; the valve is opened until the space within is evacuated. The valve is closed and observers are challenged to separate the hemispheres, which they cannot. When the valve is opened, the spheres fall apart of their own weight. This demonstration was first performed by the mayor of Magdeburg, Germany, Otto von Guericke, in 1654.
Museum of the History of Science, Geneva, Switzerland. Reproduction of a type IV thermometer of the Accademia del Cimento of Florence Italy of the 17th century. (The somewhat popular Galileo floating bulbs in a cylinder thermometer is type V.)
PharmazieHistorisches Museum, Basel, Switzerland.
PharmazieHistorisches Museum, Basel, Switzerland. Antimony cup for administering medicines. Alchemists believed that the administering vessel affected the power of the medicine.
PharmazieHistorisches Museum, Basel, Switzerland. Alchemist's laboratory. Note bellows for intensifying the fire.
PharmazieHistorisches Museum, Basel, Switzerland. Dobereiner's Lamp: "zink und salzsaure wurd wasserstoff." Inside the lighter, a piece of zinc (not present here) is suspended in the center chamber above (hydrochloric) acid. When the valve at the top is opened, gas escapes, and the level of acid rises so that it makes contact with zinc, generating hydrogen gas. The emitted hydrogen gas flows out the valve and over platinum, which catalyzes its combustion with oxygen (in the air). Thus, one can light one's cigar. Such lighters were popular among the wealthy in the second half of the 19th century in Europe.
PharmazieHistorisches Museum, Basel, Switzerland. Voltaic pile, note glass insulating rod and wooden ends.
PharmazieHistorisches Museum, Basel, Switzerland. Hand balance, of the type used by a goldsmith, a jeweler, or a pharmacist.
PharmazieHistorisches Museum, Basel, Switzerland. Hydrometers, used to measure liquid density. The higher the hydrometer floats in the liquid, the more dense the liquid is.
PharmazieHistorisches Museum, Basel, Switzerland. Apothecary's balance. Possibly this elaborate, gaudy balance was for display only.
PharmazieHistorisches Museum, Basel, Switzerland. Eighteenth-century laboratory.
PharmazieHistorisches Museum, Basel, Switzerland. Eighteenth-century laboratory.
PharmazieHistorisches Museum, Basel, Switzerland. Glassware, bent funnels.
University of Heidelberg, Heidelberg, Germany. Death mask of Robert Bunsen.
University of Heidelberg, Heidelberg, Germany. Retort used by Robert Bunsen.
Liebig Museum, Giessen, Germany. Liebig Museum in Giessen, Germany.
Liebig Museum, Giessen, Germany. Early hood. Later this chimney corner was used for rough work.
Liebig Museum, Giessen, Germany. Flasks and retorts, alembics and corcubits. Cast iron flask holders reduce breakage by support and heat distribution. Vessels to be heated have thin walls; thick walls break.
Liebig Museum, Giessen, Germany. Central charcoal oven. Note absence of fume hood.
Liebig Museum, Giessen, Germany. Sample of the element cesium, prepared by Robert Bunsen, who discovered the element spectroscopically.
Liebig Museum, Giessen, Germany. Liebig's balance. Built by Geissen cabinet maker. Has capacity of 300 g and sensitivity of 3 mg.
Liebig Museum, Giessen, Germany. Liebig's Kaliapparat, designed to absorb the carbon dioxide produced during combustion into a solution of KOH. 2 KOH + CO2 --> K2CO3 + H2O.
Liebig Museum, Giessen, Germany. Liebig's blowpipe, used to identify substances based on the color they impart to an intense flame or the color they give to a borax or soda ash glass.
Liebig Museum, Giessen, Germany. Liebig's personal hood, located in a corner of his office.
Liebig Museum, Giessen, Germany. Liebig condenser. Note that water goes in at the bottom and out at the top.
Liebig Museum, Giessen, Germany. Liebig's main laboratory. According to the curator, World War II bombing reduced this building to rubble. Only the floors are original.
Liebig Museum, Giessen, Germany. Original Kaliapparat, c. 1850.
Liebig Museum, Giessen, Germany. Filtration nach [in the manner of] Berzelius.
Liebig Museum, Giessen, Germany. Liebig laboratory benches.
Hunterian Museum of the University of Glasgow, Scotland. Rowland diffraction grating, given to Kelvin by "The Coefficients," who attended Kelvin's lectures in Baltimore.
Royal Institution, London, England. Michael Faraday's samples, with which he investigated diamagnetism.
Museum Boerhaave, Leiden, Netherlands. Linnaeus's drawings for a garden planta of George Clifford, where he developed his classification scheme.