Science & Mathematics

Chemical Balance

The Museum's collections hold thousands of objects related to chemistry, biology, physics, astronomy, and other sciences. Instruments range from early American telescopes to lasers. Rare glassware and other artifacts from the laboratory of Joseph Priestley, the discoverer of oxygen, are among the scientific treasures here. A Gilbert chemistry set of about 1937 and other objects testify to the pleasures of amateur science. Artifacts also help illuminate the social and political history of biology and the roles of women and minorities in science.

The mathematics collection holds artifacts from slide rules and flash cards to code-breaking equipment. More than 1,000 models demonstrate some of the problems and principles of mathematics, and 80 abstract paintings by illustrator and cartoonist Crockett Johnson show his visual interpretations of mathematical theorems.

Topic: Mathematics

Painting - Equal Areas, Their Triangular Square Root and Pi

This painting, based on a construction of Crockett Johnson, shows a central brown circle, a blue square, and a pink rectangle of equal area. Assuming the radius ot the circle is one, this area equals pi.
Description
This painting, based on a construction of Crockett Johnson, shows a central brown circle, a blue square, and a pink rectangle of equal area. Assuming the radius ot the circle is one, this area equals pi. The blue triangle has an approximate area of square root of pi, presenting the "triangular square root" in the title.
The diagram is from Crockett Johnson's papers. It begins with construction of a circle of radius one (the smaller circle with center X in the figure) and assumes he could find the square root of pi and construct the line XC equal to this as a side of the square shown. Assuming he can do this, the area of the square is pi. He then draws a circle of radius 2 centered at X , which intersects the square at F and extensions of the line XC at A and at N. Bisecting FX at O, he can draw a second unit circle centered at O. He joined A to B and F to N to obtain triangles XAB and XNF. Next, the artist constructed the semicircle with that intersects circle O at point I and the larger circle at point K. He then drew diameter KP and extended FI to H with IH = 1. To complete the illustration, Crockett Johnson outlined rectangle with sides HI and IP.
To show that the construction is correct, note that XC = JF = √(pi) because the square with side XC and circle O both have area pi. Triangle XNF = (1/2)(XN)(JF) = (1/2)(2)(√(pi)) = √(pi). To show that the rectangle with sides PI and HI has area pi observe that right triangle PIF is congruent to right triangle PFK. Thus P/IPF = PF/PK and PI = (PF)²/(PK) = (2JF)²/PK = 4(JF)²/PK = 4(√((pi))²)/4 = pi. So, the rectangle has area (HI)(PI) = (1)(pi) = pi, and the demonstration is complete.
This painting is executed in oil on masonite and is #90 in the series. The figures of the painting that display the painting’s title are colored in bright, bold colors while those shapes that constitute the background are less drastically highlighted. Thus, Crockett Johnson uses color to distinguish the important features of his construction.
This painting is unsigned and its date of completion is unknown.
Location
Currently not on view
date made
1970-1975
painter
Johnson, Crockett
ID Number
1979.1093.59
catalog number
1979.1093.59
accession number
1979.1093

Sau 3AI

This silver metal canister once contained Sau 3AI, an enzyme commonly used in molecular biology.
Description (Brief)
This silver metal canister once contained Sau 3AI, an enzyme commonly used in molecular biology. Sau 3AI belongs to a class of enzymes known as restriction enzymes, which are useful for their ability to cleave DNA only at locations containing specific sequences of nucleotides, the small chemical units which make up the longer DNA molecule. Sau 3AI recognizes the sequence GATC and will cut before the G.
This particular canister of Sau 3AI was used to create recombinant DNA molecules at Genentech, a biotechnology company, in the early 1980s.
Source:
GeneON, “Sau3AI.” http://www.taq-dna.com/sau3ai-_91.html
Location
Currently not on view
date made
1985-09
user
Genentech, Inc.
ID Number
2012.0198.28
accession number
2012.0198
catalog number
2012.0198.28

Hind III

This silver metal canister once contained Hind III, an enzyme commonly used in molecular biology.
Description (Brief)
This silver metal canister once contained Hind III, an enzyme commonly used in molecular biology. Hind III belongs to a class of enzymes known as restriction enzymes, which are useful for their ability to cleave DNA only at locations containing specific sequences of nucleotides, the small chemical units that make up the longer DNA molecule. Hind III recognizes the sequence TTCGAA and will cut between the A’s.
This particular canister of Hind III was used to create recombinant DNA molecules at Genentech, a biotechnology company, in the early 1980s.
Source:
GeneON, “Hind III.” http://www.taq-dna.com/hindiii-_76.html
Location
Currently not on view
date made
1985-01
user
Genentech, Inc.
ID Number
2012.0198.29
accession number
2012.0198
catalog number
2012.0198.29

Publication Plate

This publication plate was used in an article in Science, “RNA Codewords and Protein Synthesis” by Marshall Nirenberg and Philip Leder. It describes results from the National Institute of Health lab of Dr.
Description (Brief)
This publication plate was used in an article in Science, “RNA Codewords and Protein Synthesis” by Marshall Nirenberg and Philip Leder. It describes results from the National Institute of Health lab of Dr. Marshall Nirenberg, a scientist who won the 1968 Nobel Prize in Physiology or Medicine for his work in helping to “crack the genetic code,” or to understand the way DNA codes for the amino acids that are linked to build proteins.
By the late 1950s, scientists understood that DNA was the molecule containing the instructions for life. The structure of DNA was also known-- a sort of twisted ladder shape known as double helix where the “side rails” consisted of a sugar phosphate backbone and the “rungs” were made of paired nucleic acid bases (represented by A, T, G, C). The structure suggested that the order of the bases formed a code representing the order in which amino acids should be joined to produce different kinds of proteins.
But what was the code? What order of bases made up the “code words” or "codons” DNA used to represent each of the 20 amino acids? Researchers hypothesized that each codon for amino acid would be three bases long. If it was only two bases long, that would allow for only 16 different combinations of the four bases (4^2 = 16). If each codon was three bases however, that would result in 64 possible codons (4^3 =64), plenty of codons to represent each of the 20 amino acids separately.
With this knowledge, Dr. Nirenberg and his colleagues set about trying to figure out which three-base combinations represented each amino acid. It was known at the time that DNA is “transcribed” into a template RNA that interacts with ribosomes in the cell to produce proteins. Because RNA, not DNA, is what the cell reads directly to make proteins, Dr. Nirenberg reasoned that he could use a man-made stand-in for RNA that had a repeating known sequence (the same codon over and over) to produce proteins consisting of only one amino acid.
These stand-ins were known as “oligonucleotides” (see object 2001.0023.02). Using a cell-free system (one that has all the necessary parts for protein synthesis in a test tube rather than in a cell) Dr. Nirenberg introduced the oligonucleotides, consisting only of a single base, uracil, represented by U, over and over. This meant the only codon that could be read by the system was UUU or “poly-U.”
He then fed the system a supply of all 20 amino acids, one of which was radioactively labeled. Twenty different experiments were done, with only a single kind of amino acid radioactively labeled per experiment. Only when the cell was supplied with the radioactively labeled amino acid, phenylalanine, did the specially made poly-U oligonucleotide produce a radioactive protein. Nirenberg had demonstrated that the codon “UUU” is the code word for phenylalanine, and in doing so, he had cracked the first word in the genetic code.
Within five years, between the work of Nirenberg and that of several scientists using similar methods, the code for the remaining 63 codons would be understood.
Location
Currently not on view
ID Number
2001.0023.06
accession number
2001.0023
catalog number
2001.0023.06

Patent Order Punch Cards

This set of six orange punch cards each have 53 columns. The standard IBM punch card has 80 columns.
Description
This set of six orange punch cards each have 53 columns. The standard IBM punch card has 80 columns. Each card is marked PO-33, PATENT ORDER (Letter Unit) on the left edge, and IBM D7 7517 on the bottom edge.
The following information is punched and printed on each card, the unique patent number, the same customer number (11530), month (01), day (29), and serv. code (6M). These cards were used by the U.S. Patent Office when filling requests for copies of patents.
Location
Currently not on view
maker
IBM
ID Number
2017.3122.02
nonaccession number
2017.3122
catalog number
2017.3122.02

Opera Glasses

This is a brass instrument with ivory focusing screw, handle, and covering over the cylindrical barrels. The objective lenses are 24 mm diameter. “LUNETTE PAR INVENTION ET PERFECTIONEMENT*” appears around each eyepiece.
Description
This is a brass instrument with ivory focusing screw, handle, and covering over the cylindrical barrels. The objective lenses are 24 mm diameter. “LUNETTE PAR INVENTION ET PERFECTIONEMENT*” appears around each eyepiece. The case is made of black cellulose nitrate.
Location
Currently not on view
date made
mid 19th century
ID Number
PH.336789
catalog number
336789
accession number
1978.2216

Macroprojectiles

These macroprojectiles are part of the firing mechanism for a biolistic gene gun prototype produced by John Sanford, Ed Wolf, and Nelson Allen at Cornell University in Ithaca, New York.
Description (Brief)
These macroprojectiles are part of the firing mechanism for a biolistic gene gun prototype produced by John Sanford, Ed Wolf, and Nelson Allen at Cornell University in Ithaca, New York. Biolistic gene guns are used to genetically transform plants, by shooting microprojectiles (tiny bullets) covered in DNA into plant cells.
The firing mechanism of the gene gun required several steps. A gunpowder charge (see object 1991.0785.03.2) or compressed air was used to accelerate a macroprojectile, upon whose tip rested DNA-coated microprojectiles. The macroprojectile would be halted on impact with a stopping plate (see object 1991.0785.03.4). A hole in the stopping plate was small enough to allow the microprojectiles to pass through, but large enough to halt the macroprojectile (see object 1991.0785.03.5). The microparticles would then continue to move forward, eventually penetrating the cells to be transformed. The process is diagrammed in the Biolistic Gene Transfer Process shadow box (see object 1992.0023.01).
To learn more about biolistic gene guns, please see gene gun
prototype II (object number 1991.0785.02) or gene gun prototype III (object number 1991.0785.01.1).
Location
Currently not on view
ID Number
1991.0785.03.3
catalog number
1991.0785.03.3
accession number
1991.0785

Humulin BR, Buffered Regular, insulin human injection, USP, recombinant DNA origin

Humulin is human insulin used for treating diabetes. Prior to its development, diabetics used insulin isolated from pig and cow pancreases.
Description (Brief)
Humulin is human insulin used for treating diabetes. Prior to its development, diabetics used insulin isolated from pig and cow pancreases. Developed by Genentech, the first American biotechnology company, Humulin was licensed to Eli Lilly and became the first marketable product created through recombinant DNA technology. Its licensing by the FDA in October 1982 also made it the first recombinant pharmaceutical approved for use in the United States.
Recombinant pharmaceuticals are created by inserting genes from one species into a host species, often yeast or bacteria, where they do not naturally occur. The genes code for a desired product, and therefore the genetically modified host organisms can be grown and used as a kind of living factory to produce the product. In this case, genes coding for human insulin are inserted into bacteria. Bacteria produce insulin, which is harvested and used as the active ingredient in Humulin.
Humulin BR is similar to regular insulin in activity and action, but it was formulated to be used specifically and only in the external insulin pump.
Object consists of a white cardboard box with black and red printing. Box contains two product inserts and one round clear glass bottle with an orange plastic cap and a white label. Bottle contains a yellowish, clear solution.
Location
Currently not on view
date made
1987
maker
Eli Lilly and Company
ID Number
1987.0790.02
accession number
1987.0790
catalog number
1987.0790.02

Painting - Problem of Delos Constructed from a Solution by Isaac Newton (Arithmetica Universalis)

Two paintings in the Crockett Johnson collection concern the ancient problem of doubling the volume of a given cube, or the problem of Delos.
Description
Two paintings in the Crockett Johnson collection concern the ancient problem of doubling the volume of a given cube, or the problem of Delos. Crockett Johnson wrote of this problem: "Plutarch mentions it, crediting as his source a now lost version of the legend written by the third century BC Alexandrian Greek astronomer Eratosthenes, who first measured the size of the Earth. Suffering from plague, Athens sent a delegation to Delos, Apollo’s birthplace, to consult its oracle. The oracle’s instruction to the Athenians, to double the size of their cubical altar stone, presented an impossible problem. . . ."(p. 99). Hence the reference to the problem of Delos in the title of the painting.
Isaac Newton suggested a solution to the problem in his book Arithmetica Universalis, first published in 1707. His construction served as the basis of the painting. Newton’s figure, as redrawn by Crockett Johnson, begins with a base (OA), bisected at a point (B), with an equilateral triangle (OCB) constructed on one of the halves of the base. Newton then extended the sides of this triangle through one vertex. Placing a marked straightedge at one end of the base (O), he rotated the rule so that the distance between the two lines extended equaled the sides of the triangle (in the figure, DE = OB = BA = OC = BC). If these line segments are of length one, one can show that the line segment OD is of length equal to the cube root of two, as desired.
In Crockett Johnson’s painting, the line OA slants across the bottom and the line ODE is vertical on the left. The four squares drawn from the upper left corner (point E) have sides of length 1, the cube root of 2, the cube root of 4, and two. The distance DE (1) represents the edge of the side and the volume of a unit cube, while the sides of three larger squares represent the edge (the cube root of 2), the side (the square of the cube root of 2) and the volume (the cube of the cube root of two) of the doubled cube.
This oil painting on masonite is #56 in the series and dates from 1970. The work is signed: CJ70. It is inscribed on the back: PROBLEM OF DELOS (/) CONSTRUCTED FROM A SOLUTION BY (/) ISAAC NEWTON (ARITHMETICA UNIVERSALIS) (/) Crockett Johnson 1970. The painting has a wood and metal frame. For related documentation see 1979.3083.04.06. See also painting number 85 (1979.1093.55), with the references given there.
Reference: Crockett Johnson, “On the Mathematics of Geometry in My Abstract Paintings,” Leonardo 5 (1972): pp. 98–9.
date made
1970
referenced
Newton, Isaac
painter
Johnson, Crockett
ID Number
1979.1093.36
catalog number
1979.1093.36
accession number
1979.1093

Group Examination Alpha

During World War I, the U.S. Army needed to sort out the thousands of recruits arriving at training camps. Psychologists claimed that their young science offered an objective, efficient way to classify men, weeding out the mentally unfit.
Description
During World War I, the U.S. Army needed to sort out the thousands of recruits arriving at training camps. Psychologists claimed that their young science offered an objective, efficient way to classify men, weeding out the mentally unfit. Intelligence tests available at the time had been designed for children, given individually, and in many cases were unstandardized. No one knew precisely what they measured or how these measurements related to military performance. Nonetheless, over 1,700,000 American soldiers took intelligence tests during the war.
Group Examination Alpha was for men who could read English. It tested the ability to follow oral directions, arithmetic, vocabulary, pattern recognition, general information, and “common sense.”
Location
Currently not on view
date made
1918
maker
United States Army. Medical Department. Division of Psychology
ID Number
1990.0334.01
catalog number
1990.0334.01
accession number
1990.0334

Mosquitoes Preserved in Plastic

Currently not on view
Location
Currently not on view
ID Number
AG.A.7568
catalog number
A.7568
accession number
198812

Red Anemone Preserved in Plastic

Currently not on view
Location
Currently not on view
Date made
1946
ID Number
AG.A.7554
accession number
198812
catalog number
A.7554

Joseph Priestley

In the late 1790s at the behest of the American Philosophical Society, the American artist, Gilbert Stuart (1756-1828), began working on a half-length oil portrait of Joseph Priestley, the famous English chemist and political dissident who had recently settled in the United State
Description
In the late 1790s at the behest of the American Philosophical Society, the American artist, Gilbert Stuart (1756-1828), began working on a half-length oil portrait of Joseph Priestley, the famous English chemist and political dissident who had recently settled in the United States. This portrait showed Priestley wearing a white stock and dark vest and jacket, his head turned slightly to his right, his hair parted in the middle and hanging low on his neck.
Although he had received American funds for this project, Stuart sold the portrait to T. B. Barclay, an Englishman who visited his Boston studio. After taking the painting to his home near Liverpool, Barclay hired an English artist named William Artaud to complete the parts that Stuart had left unfinished. He also let Artaud make three oil copies of the portrait. One copy came into the possession of Priestley’s descendants in Pennsylvania, and it was from this that American artist, Albert Rosenthal (1863-1939), made this copy. The American Chemical Society presented to the Smithsonian in 1921.
Ref: Henry C. Bolton, ed., The Scientific Correspondence of Joseph Priestley (New York, 1892), pp. 177-179.
Robert E. Schofield, The Enlightened Joseph Priestley (University Park, Pa., 2004).
Edgar Fahs Smith to Albert Rosenthal, Oct. 28, 1921, in Albert Rosenthal papers, Archives of American Art.
Charles M. Mount, “Gilbert Stuart in Washington: With a Catalogue of his Portraits Painted between December 1803 and July 1805,” Records of the Columbia Historical Society 71-72 (1972): 81-127, on pp. 103, 119.
Location
Currently not on view
ID Number
PH.318492
catalog number
318492
accession number
67389

Milestones in Microbiology 1895-1995

Currently not on view
Location
Currently not on view
date made
1995
maker
Difco Laboratories
ID Number
1995.3058.036
nonaccession number
1995.3058
catalog number
1995.3058.036

Caere Button, Addition

This square button has a white background with a green border. Black text inside the border reads: Addition. Addition 1. a part added; thus increasing the number of, 2. joining of one thing to another. On the bottom left is the CAERE logo.
Description
This square button has a white background with a green border. Black text inside the border reads: Addition. Addition 1. a part added; thus increasing the number of, 2. joining of one thing to another. On the bottom left is the CAERE logo. A mark in black ink on the reverse reads: Comdex 11/89.
Location
Currently not on view
date made
c 1989
ID Number
2009.3071.210
catalog number
2009.3071.210
nonaccession number
2009.3071

Painting - Squared Circle

This oil painting on pressed wood, #52 in the series, shows an original construction of Crockett Johnson. He executed this work in 1968, three years after he began creating mathematical paintings.
Description
This oil painting on pressed wood, #52 in the series, shows an original construction of Crockett Johnson. He executed this work in 1968, three years after he began creating mathematical paintings. It is evident that the artist was very proud of this construction because he drew four paintings dealing with the problem of squaring the circle. The construction was part of Crockett Johnson's first original mathematical work, published in The Mathematical Gazette in early 1970. A diagram relating to the painting was published there.
To "square a circle," mathematically speaking, is to construct a square whose area is equal to that of a given circle using only a straightedge (an unmarked ruler) and a compass. It is an ancient problem dating from the time of Euclid and is one of three problems that eluded Greek geometers and continued to elude mathematicians for 2,000 years. In 1880, the German mathematician Ferdinand von Lindermann showed that squaring a circle in this way is impossible - pi is a transcendental number. Because this proof is complicated and difficult to understand, the problem of squaring a circle continues to attract amateur mathematicians like Crockett Johnson. Although he ultimately understood that the circle cannot be squared with a straightedge and compass, he managed to construct an approximate squaring.
Crockett Johnson began his construction with a circle of radius one. In this circle he inscribed a square. Therefore, in the figure, AO=OB=1 and OC=BC=√(2) / 2. AC=AO+OC=1 + √(2) / 2 and AB=√(AC² + BC²) which equals the square root of the quantity (2+√(2)). Crockett Johnson let N be the midpoint of OT and constructed KN parallel to AC. K is thus the midpoint of AB, and KN=AO - (AC)/2=1/2 - √(2) / 4. Next, he let P be the midpoint of OG, and he drew KP, which intersects AO at X. Crockett Johnson then computed NP=NO+OP=(√(2))/4+(1/2). Triangle POX is similar to triangle PNK, so XO/OP=KN/NP. From this equality it follows that XO=(3-2√(2))/2.
Also, AX=AO-XO=(2√(2)-1)/2 and XC=XO+OC=(3-√(2))/2. Crockett Johnson continued his approximation by constructing XY parallel to AB. It is evident that triangle XYC is similar to triangle ABC, and so XY/XC=AB/AC. This implies that XY=[√((2+√(2)) × (8-5√(2))]/2. Finally he constructed XZ=XY and computed AZ=AX+XZ=[2√(2)-1+(√(2+√(2)) × (8-5√(2))]/2 which approximately equals 1.7724386. Crockett Johnson knew that the square root of pi approximately equals 1.772454, and thus AZ is approximately equal to √(Π) - 0.000019. Knowing this value, he constructed a square with each side equal to AZ. The area of this square is (AZ)² = 3.1415258. This differs from the area of the circle by less than 0.0001. Thus, Crockett Johnson approximately squared the circle.
The painting is signed: CJ68. It is marked on the back: SQUARED CIRCLE* (/) Crockett Johnson 1968 (/) FLAT OIL ON PRESSED WOOD) (/) MATHEMATICALLY (/) DEMONSTRATED (/) TO √π + 0.000000001. It has a white wooden frame. Compare to painting #91 (1979.1093.60).
References: Crockett Johnson, “On the Mathematics of Geometry in My Abstract Paintings,” Leonardo 5 (1972): p. 98.
C. Johnson, “A Geometrical look at √π," Mathematical Gazette, 54 (1970): p. 59–60. the figure is from p. 59.
Location
Currently not on view
date made
1968
painter
Johnson, Crockett
ID Number
1979.1093.35
catalog number
1979.1093.35
accession number
1979.1093

Carrot Slices Preserved in Plastic

Currently not on view
Location
Currently not on view
date made
1940-04-15
ID Number
AG.A.7552
catalog number
A.7552
accession number
198812

Experimental Ruby Laser

This is an experimental ruby laser made in 1963 at Ohio State University.
Description
This is an experimental ruby laser made in 1963 at Ohio State University. Edward Damon, a researcher at the University’s Antenna Laboratory, made this and several other lasers during his investigation of Theodore Maiman’s ruby laser experiments of three years earlier.
In addition to replicating Maiman's 1960 experiments, Damon wished to explore variations of the ruby laser. Unlike Maiman's laser, this laser does not use a spiral flashlamp to energize the ruby crystal. Instead, Damon placed three linear flashlamps parallel to the rod-shaped laser crystal. Firing these lamps simultaneously provided energy to the crystal. The laser also demonstrates a water cooling technique still used in some lasers today.
Location
Currently not on view
date made
1963
ID Number
2009.0228.02
accession number
2009.0228
catalog number
2009.0228.02

Painting - Heptagon from Its Seven Sides

Toward the end of his life, Crockett Johnson took up the problem of constructing a regular seven-sided polygon or heptagon. This construction, as Gauss had demonstrated, requires more than a straight edge and compass.
Description
Toward the end of his life, Crockett Johnson took up the problem of constructing a regular seven-sided polygon or heptagon. This construction, as Gauss had demonstrated, requires more than a straight edge and compass. Crockett Johnson used compass and a straight edge with a unit length marked on it. Archimedes and Newton had suggested that constructions of this sort could be used to trisect the angle and to find a cube with twice the volume of a given cube, and Crockett Johnson followed their example.
One may construct a heptagon given an angle of pi divided by seven. If an isosceles triangle with this vertex angle is inscribed in a circle, the base of the triangle will have the length of one side of a regular heptagon inscribed in that circle. According to Crockett Johnson's later account, in the fall of 1973, while having lunch in the city of Syracuse on Sicily during a tour of the Mediterranean, he toyed with seven toothpicks, arranging them in various patterns. Eventually he created an angle with his menu and wine list and arranged the seven toothpicks within the angle in crisscross patterns until his arrangement appeared as is shown in the painting.
Crockett Johnson realized that the vertex angle of the large isosceles triangle shown is exactly π/7 radians, as desired. The argument suggested by his diagram is more complex than what he later published. The numerical results shown in the figure suggest his willingness to carry out detailed calculations.
Heptagon from its Seven Sides, painted in 1973 and #107 in the series, shows a triangle with purple and white sections on a navy blue background. This oil or acrylic painting on masonite is signed on its back : HEPTAGON FROM (/) ITS SEVEN SIDES (/) (Color sketch for larger painting) (/) Crockett Johnson 1973. No larger painting on this pattern is at the Smithsonian.
Reference: Crockett Johnson, "A Construction for a Regular Heptagon," Mathematical Gazette, 1975, vol. 59, pp. 17–21.
Location
Currently not on view
date made
1973
painter
Johnson, Crockett
ID Number
1979.1093.74
catalog number
1979.1093.74
accession number
1979.1093

It's a BioWorld! Poster

This brightly colored poster shows a timeline of events in the history of genetics and biotechnology along the top and bottom edges.
Description (Brief)
This brightly colored poster shows a timeline of events in the history of genetics and biotechnology along the top and bottom edges. Events range from Mendel's experiments with pea plants on heredity in the mid-1800s to the first patent awarded for a genetically engineered mammal in 1988. The left and right edges of the poster list biotech companies and funders. The center of the poster depicts applications of biotechnology to medicine, agriculture, industry, and the environment. It was collected at the International Biotechnology Expo in 1990.
Location
Currently not on view
date made
ca 1990
ID Number
1990.3203.01
catalog number
1990.3203.01
nonaccession number
1990.3203

Cylinder-type Electrostatic Machine

People from ancient times knew that rubbing certain materials and then touching something caused a spark. Studying what is called electrostatics laid the groundwork for understanding electricity and magnetism.
Description (Brief)
People from ancient times knew that rubbing certain materials and then touching something caused a spark. Studying what is called electrostatics laid the groundwork for understanding electricity and magnetism. Natural philosophers, scientists, and instrument makers created many ingenious devices to generate electrostatic charges starting in the 1600s. These machines varied in size and technique but all involved rotary motion to generate a charge, and a means of transferring the charge to a storage device for use.
This machine was made in London by Edward Palmer (1803–1872) about 1840. The leather rubbing pad with a silk flap rides against one side of the cylinder and a brass prime conductor on the other side collects the charge with a brass comb. Both are mounted on insulating glass rods. A screw mechanism at the bottom adjusts the tension of the rubbing pad more precisely. During the 1750s electrical researchers refined the design of electrostatic machines by replacing earlier spherical globes with a glass cylinder, a design used for many years. This change increased the surface area of the glass in contact with the rubbing pad and improved the efficiency of the generator. Palmer sold microscopes and other scientific supplies from his shop on Newgate Street from about 1837 to about 1845 when he sold his business.
Location
Currently not on view
date made
ca 1840
maker
Palmer, E.
ID Number
EM.319503
catalog number
319503
accession number
238500

The Human Genome 1990

Currently not on view
Location
Currently not on view
date made
1990
ID Number
2013.3064.06
catalog number
2013.3064.06
nonaccession number
2013.3064

Heroes of Microbiology / Ruth Ella Moore / William A. Hinton / Eugene Cota-Robles

Currently not on view
Location
Currently not on view
date made
1997
ID Number
2000.3047.013
catalog number
2000.3047.013
nonaccession number
2000.3047

Wimshurst-type influence machine

People from ancient times knew that rubbing certain materials and then touching something caused a spark. Studying what is called electrostatics laid the groundwork for understanding electricity and magnetism.
Description (Brief)
People from ancient times knew that rubbing certain materials and then touching something caused a spark. Studying what is called electrostatics laid the groundwork for understanding electricity and magnetism. Natural philosophers, scientists, and instrument makers created many ingenious devices to generate electrostatic charges starting in the 1600s. These machines varied in size and technique but all involved rotary motion to generate a charge, and a means of transferring the charge to a storage device for use.
Many early electrostatic machines generated a charge by friction. In the later 19th century several designs were introduced based on induction. Electrostatic induction occurs when one charged body (such as a glass disc) causes another body (another disc) that is close but not touching to become charged. The first glass disc is said to influence the second disc so these generators came to be called influence machines.
Heinrich Wommelsdorf (1877-1945) of Germany designed this influence machine in the early 1910s. Wommelsdorf was trying to improve the older designs of August Toepler and Wilhelm Holtz. First he used discs made of plastic rather than glass or shellac. He placed metallic inductors called sectors between the two discs making a single rotor assembly. Instead of a fixed disc, the casings that cover the corners of the rotor carry the charge to the Leyden jars. As Wommelsdorf explained in US Patent 1071196, “the charges on the carriers are conducted away from the peripheral edge of the disc...instead of from the axis or laterally..., as has hitherto been usual.” He believed that change increased the efficiency of the machine by capturing more of the charge. He established the Berliner Elektros Gesellschaft in 1913 to produce this design that he called a Kondensatormaschine (condenser machine).
Location
Currently not on view
date made
ca 1920
ID Number
EM.330309
catalog number
330309
accession number
287887

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