Engineering, Building, and Architecture

Engine Room From Coast Guard Buoy Tender Oak

Not many museums collect houses. The National Museum of American History has four, as well as two outbuildings, 11 rooms, an elevator, many building components, and some architectural elements from the White House. Drafting manuals are supplemented by many prints of buildings and other architectural subjects. The breadth of the museum's collections adds some surprising objects to these holdings, such as fans, purses, handkerchiefs, T-shirts, and other objects bearing images of buildings.

The engineering artifacts document the history of civil and mechanical engineering in the United States. So far, the Museum has declined to collect dams, skyscrapers, and bridges, but these and other important engineering achievements are preserved through blueprints, drawings, models, photographs, sketches, paintings, technical reports, and field notes.

Place: Massachusetts

Thompson Steam Engine Indicator

The American Steam Gauge Co. of Boston, Massachusetts, manufactured this steam engine indicator, serial number 1875. J.W.
Description
The American Steam Gauge Co. of Boston, Massachusetts, manufactured this steam engine indicator, serial number 1875. J.W. Thompson patented this style of indicator on August 31, 1875, patent number 167,364.
An engine indicator is an instrument for graphically recording the pressure versus piston displacement through an engine stroke cycle. Engineers use the resulting diagram to check the design and performance of the engine.
A mechanical indicator consists of a piston, spring, stylus, and recording system. The gas pressure of the cylinder deflects the piston and pushes against the spring, creating a linear relationship between the gas pressure and the deflection of the piston against the spring. The deflection is recorded by the stylus on a rotating drum that is connected to the piston. Most indicators incorporate a mechanical linkage to amplify the movement of the piston to increase the scale of the record.
When the ratio of the frequency of the pressure variation to the natural frequency of the system is small, then the dynamic deflection is equal to the static deflection. To design a system with a high natural frequency, the mass of the piston, spring, stylus, and mechanical linkage must be small, but the stiffness of the spring must be high. The indicator is subjected to high temperatures and pressures and rapid oscillations, imposing a limitation on the reduction in mass. Too stiff a spring will result in a small displacement of the indicator piston and a record too small to measure with accuracy. Multiplication of the displacement will introduce mechanical ad dynamic errors.
The parameters of the problem for designing an accurate and trouble free recorder are such that there is no easy or simple solution. Studying the variety of indicators in the collection shows how different inventors made different compromises in their designs.
Location
Currently not on view
ID Number
MC.316801
catalog number
316801
accession number
228496
patent number
2547

Greene-Wheelock Valve and Valve Seat Model

This model represents a skeletonized taper plug in which are formed two gridiron valve seats and a bonnet that carried a rockarm collar and cams for actuating one steam and one exhaust valve on the valve seats.
Description
This model represents a skeletonized taper plug in which are formed two gridiron valve seats and a bonnet that carried a rockarm collar and cams for actuating one steam and one exhaust valve on the valve seats. The valves are long narrow gridiron valves, which reciprocate in the direction parallel to the axis of the plug. They are actuated by rods and slides and roller cams, which are rock shaft on the collar. The steam valve slide has a disengaging pawl to provide an adjustable cut-off.
Reference:
This description comes from the 1939 Catalog of the Mechanical Collections of the Division of Engineering United States Museum Bulletin 173 by Frank A. Taylor.
Location
Currently not on view
ID Number
MC.310250
catalog number
310250
accession number
108073

Crosby Gas Engine Indicator

Crosby Steam Gauge & Valve Co. of Boston, Massachusetts, manufactured this steam engine indicator, serial number 6163.
Description
Crosby Steam Gauge & Valve Co. of Boston, Massachusetts, manufactured this steam engine indicator, serial number 6163. It consists of a small steel piston (1/8 inch); a vented brass cylinder; an internal, double wound spring, which can be changed; a small drum with a spiral spring and a single record; and a brass stylus. Accompanying the indicator is a box with fourteen springs, small tools, and an extra piston with top stem.
An engine indicator is an instrument for graphically recording the pressure versus piston displacement through an engine stroke cycle. Engineers use the resulting diagram to check the design and performance of the engine.
A mechanical indicator consists of a piston, spring, stylus, and recording system. The gas pressure of the cylinder deflects the piston and pushes against the spring, creating a linear relationship between the gas pressure and the deflection of the piston against the spring. The deflection is recorded by the stylus on a rotating drum that is connected to the piston. Most indicators incorporate a mechanical linkage to amplify the movement of the piston to increase the scale of the record.
When the ratio of the frequency of the pressure variation to the natural frequency of the system is small, then the dynamic deflection is equal to the static deflection. To design a system with a high natural frequency, the mass of the piston, spring, stylus, and mechanical linkage must be small, but the stiffness of the spring must be high. The indicator is subjected to high temperatures and pressures and rapid oscillations, imposing a limitation on the reduction in mass. Too stiff a spring will result in a small displacement of the indicator piston and a record too small to measure with accuracy. Multiplication of the displacement will introduce mechanical ad dynamic errors.
The parameters of the problem for designing an accurate and trouble free recorder are such that there is no easy or simple solution. Studying the variety of indicators in the collection shows how different inventors made different compromises in their designs.
Location
Currently not on view
maker
Crosby Steam Gage & Valve Company
ID Number
MC.316799
catalog number
316799
accession number
228496
patent number
6163

Crane Hot-Air Engine, Patent Model

This model was submitted with the application to the U.S. Patent Office for the Patent no. 46084, issued to Moses G.
Description
This model was submitted with the application to the U.S. Patent Office for the Patent no. 46084, issued to Moses G. Crane, of Newtown, Massachusetts, January 31, 1865.
This engine consists of one vertical work cylinder and two pump or air-transfer cylinders connected to two furnaces. In operation two separate quantities of air are used repeatedly. One quantity of air is circulated between one furnace and the upper end of the work cylinder by one of the air pumps, while the other charge of air is supplied from the other furnace to the lower end of the work cylinder. In each case the air is heated in the furnace, transferred to the work cylinder, allowed to expand doing work against the piston, and is then returned to the furnace by the pump, to be reheated. The pump pistons and valves are actuated by slotted bell cranks on the ends of the engine crankshaft.
Reference:
This description comes from the 1939 Catalog of the Mechanical Collections of the Division of Engineering United States Museum Bulletin 173 by Frank A. Taylor.
Location
Currently not on view
date made
1865
patent date
1865-01-31
inventor
Crane, Moses G.
ID Number
MC.308670
catalog number
308670
accession number
89797
patent number
46,084

Model of a Controlled Forced Circulation Boiler, 1942

This model represents the first major controlled circulation boiler in the United States. It was installed at the Somerset, Massachusetts Station of the Montaup Electric Company in 1942.
Description
This model represents the first major controlled circulation boiler in the United States. It was installed at the Somerset, Massachusetts Station of the Montaup Electric Company in 1942. Shortly thereafter the controlled circulation concept reached full commercial development and was widely used in public utility central stations throughout the world.
The history of steam power is one of increasing steam pressures in search of increased efficiency. However, with higher pressures the natural circulation of water of varying densities within the boiler's many circuits becomes less effective.
In controlled circulation boilers, water is continuously and rapidly circulated by pumps which are completely independent of the feed water pumps and thus operate with a relatively small pressure differential. By forcing the water's circulation, the elements of the boiler can be located without regard to hydraulic head, and because frictional loss is not a consideration, smaller tubes can be used. Further, heat is transferred from the fire to the water more efficiently.
The actual boiler this model represents could produce 650,000 pounds of steam per hour at 2,000 pounds per square inch pressure. It contained a volume of 7,800 gallons of water which the pumps could recirculate in just one minute.
date made
1941-1942
ID Number
MC.326787
catalog number
326787
accession number
263167

Sturtevant’s Patent Model of a Heating and Ventilating Apparatus – ca 1870

This model was filed with the application to the U.S. Patent Office for Patent Number 100,211 issued to B. F. Sturtevant of Jamaica Plains, MA on February 22, 1870.
Description
This model was filed with the application to the U.S. Patent Office for Patent Number 100,211 issued to B. F. Sturtevant of Jamaica Plains, MA on February 22, 1870. The patent described a forced air heating system consisting of a steam producing boiler, a steam engine to drive a centrifugal wheel fan for circulating air, a heat exchanger to heat the air via the combustion products of the boiler, a condenser utilizing the circulating air to return the steam to water for reuse, and a series of duct work and valves. The patent model illustrates only the central duct work, heat exchanger and steam condenser. Diagrams showing the complete heating and ventilating apparatus design can be found in the patent document online (www.USPTO.gov/patents/process/search/index.jsp). In the image the upper cylinder is the steam condenser. The cylinder at the bottom represents the heat exchanger. The opening at its front is where the combustion gases from the boiler would exit via a flue or chimney. Cold air entered at the ducts at the lower right. Two separate intakes are shown – the bottom was for fresh air from outside the building and the upper for recirculated air from heated rooms. A valve allowed engineers to regulate the ratio of outside to inside air. Hot air exited at the right side of the condenser via the ductwork which was connected to the engine-driven fan’s inlet. The heated, pressurized air exited from the fan into a series of ducts that would supply heat to various parts of the building. The patent also made provisions for domestic water heating by utilizing some of the condenser’s hot water for that purpose. Sturtevant claimed his design increased efficiency by making use of hot flue gases as the primary source to heat air but also by using the remaining energy of the steam in the condenser to further heat the air. Sturtevant was extremely successful with this and his other patents (no less than 10 patents dealing with heating and ventilation were granted to him on the same day as this patent). In 1860 he founded the B. F. Sturtevant Co. which was extremely successful and long lived; Westinghouse bought the company in 1945, and operations continued at the Hyde Park, MA factory until its closing in 1989. The company’s equipment was installed in many public and private buildings including the U.S. Capitol and the “New National Museum, Washington, D.C” – now the Smithsonian National Museum of Natural History.
The patent model is constructed of brass and tin. It represents the central duct work, heat exchanger, and steam condenser of Sturtevant’s patent. The flue pipes are modelled inside the heat exchanger. The valves controlling the mixture of fresh and recirculated air are present within the inlet duct. A model of the pipe carrying exhaust steam to the condenser is also included.
Location
Currently not on view
date made
ca 1870
patent date
1870-02-22
inventor
Sturtevant, B. F.
ID Number
MC.308725
catalog number
308725
accession number
89797
patent number
100,211

Outside Spring Steam Engine Indicator with Lanza Attachment for Continuous Recording - 1930

An engine indicator is an instrument for graphically recording the cylinder pressure versus piston displacement through an engine stroke cycle. Engineers use the resulting diagram to check the design and performance of the engine.
Description
An engine indicator is an instrument for graphically recording the cylinder pressure versus piston displacement through an engine stroke cycle. Engineers use the resulting diagram to check the design and performance of the engine. The indicator portion of this unit is a 1930 Crosby Valve and Gage company external spring model. The advantage of the outside spring was isolation of the spring from the varying temperatures inside the cylinder. The continuous recording attachment was invented by Professor Gaetano Lanza of MIT and patented in 1908.
The advantage of continuous measurements is that accurate assessments can be made of engines which experience widely varying loads during portions of their work. A continuous recording mechanism had been patented by T. Davidson approximately a year prior to the Lanza patent. Lanza’s improvement was the replacement of cords attached to the engine’s piston rod with a rigid metal attachment. This eliminated errors and distortions caused by the cord stretching and variations in the return springs.
The introduction of the steam indicator in the late 1790s and early 1800s by James Watt and others had a great impact on the understanding of how the steam behaved inside the engine's cylinder and thereby enabled much more exacting and sophisticated designs. The devices also changed how the economics and efficiency of steam engines were portrayed and marketed. They helped the prospective owner of a machine better understand how much his fuel costs would be for a given amount of work performed. Measurement of fuel consumed and work delivered by the engine was begun by Watt, who in part justified the selling price of his engines on the amount of fuel cost the purchaser might save compared to an alternate engine.
In the early days of steam power, the method to compare engine performance was based on a concept termed the engine’s “duty”. It originally was calculated as the number of pounds of water raised one foot high per one bushel of coal consumed. The duty method was open to criticism due to its inability to take into consideration finer points of efficiency in real world applications of engines. Accurate determination of fuel used in relation to work performed has been fundamental to the design and improvement of all steam-driven prime movers ever since Watt’s time. And, the steam indicators’ key contribution was the accurate measurements of performance while the engine was actually doing the work it was designed to do. This indicator is the result of nearly 150 years of design and performance improvements. The Lanza attachment enabled accurate and continuous of monitoring of engines that experienced widely varying load conditions.
date made
1930
ID Number
MC.309834
catalog number
309834
accession number
109635

Crocker’s Patent Model of a Hot-Air Furnace - 1874

This model was filed with the application to the U.S. Patent Office for Patent Number 163,050 issued to William O. Crocker on May 11, 1875. Crocker’s patent was for improvements in a hot-air furnace.
Description
This model was filed with the application to the U.S. Patent Office for Patent Number 163,050 issued to William O. Crocker on May 11, 1875. Crocker’s patent was for improvements in a hot-air furnace. The coal-fired furnace design provided an inner combustion chamber which was surrounded by an intermediate metal jacket. Cold air entered at the bottom of the furnace and was communicated via a set of holes in the base into the annular space between the combustion chamber and the intermediate jacket where it was heated. The diameter of the intermediate jacket increased from the base to top of the furnace. This allowed the heated air to expand efficiently into the air chamber at the top of the furnace where it was then conveyed via ducts to the building. The intermediate jacket was surrounded by an outer casing, the purpose of which was to increase efficiency by reducing radiation of heat from the hot intermediate jacket. Another design feature which claimed to increase efficiency was provision for both direct and indirect draft for the combustion chamber. The fire-pot had vertical partitions that extended from the top of the chamber three quarters of the way to the bottom. Two flues were provided, one near the top of the combustion chamber and one just above the fire-pot. The upper flue could be closed off so that the products of combustion would have to travel up into the combustion chamber and then back down behind the partitions through the fire-pot and back up its front to the lower flue exit. The object was to more evenly distribute the heated gases over the entire surface of the combustion chamber. A review of available advertisements and trade literature of the period did not provide any information on any commercial development of Crocker’s patent.
The patent model is constructed of tin sheet. It illustrates the key design features of the patent: the outer casing, combustion chamber, and the intermediate jacket around the combustion chamber. The perforated openings at the base of the furnace which provide air circulation around the combustion chamber and intermediate jacket are clearly represented. The direct and indirect flues are also shown.
Location
Currently not on view
date made
1874
patent date
1875-05-11
inventor
Crocker, William O.
ID Number
MC.309281
catalog number
309281
accession number
89797
patent number
163,050

Sturtevant’s Patent Model of a Compound Air-Heater and Steam-Condenser – ca 1870

This model was filed with the application to the U.S. Patent Office for Patent Number 100,242 issued to B.F. Sturtevant of Jamaica Plain, Massachusetts on February 22, 1870.
Description
This model was filed with the application to the U.S. Patent Office for Patent Number 100,242 issued to B.F. Sturtevant of Jamaica Plain, Massachusetts on February 22, 1870. The patent was for an improvement in compound air-heaters and steam-condensers.
The primary elements of the patent were a centrifugal fan, a heat exchanger case and associated ductwork. The fan (based on a previous patent by Mr. Sturtevant) drew air through the heat exchanger and was intended to exhaust the heated air into distribution ductwork. The heat exchanger consisted of an inner cylinder enclosing a large number of horizontal air tubes. Steam was introduced into the cylinder via a nozzle at the top. Steam and water condensed from steam within the cylinder exited via a like nozzle at the bottom. Plates at each end sealed the cylinder to prevent steam escaping while allowing air to flow through the tubes.
Mr. Sturtevant claimed as new and improved his concept of providing an outer cylinder that enclosed the inner. This increased efficiency by causing air to flow both over the heated inside and outside surfaces of the inner cylinder. He also increased efficiency by placing deflector plates inside the steam nozzles to improve the distribution of steam across the air tubes and also to reduce the splashing of condensate at the exit. He provided for improved access for cleaning and repairs by including space between the fan housing and the heat exchanger and providing removable panels.
Sturtevant enjoyed significant commercial success with this and his other patents (no less than 10 patents dealing with heating and ventilation were granted to him on the same day as this patent). In 1860 he founded the B. F. Sturtevant Co. which was extremely successful and long lived; Westinghouse bought the company in 1945, and operations continued at the Hyde Park, MA factory until its closing in 1989. The company’s equipment was installed in many public and private buildings including the U.S. Capitol and the “New National Museum, Washington, D.C” – now the Smithsonian National Museum of Natural History.
The patent model is shown in the image. The model is highly detailed and is constructed of metal castings and brass plate. It illustrates most of the key elements of the patent to include the details of the steam nozzles, deflector plates, and the provisions for access for maintenance. Diagrams showing the complete design of the heater can be found in the patent document online (www.USPTO.gov).
Location
Currently not on view
date made
ca 1870
ca 1870
patent date
1870-02-22
inventor
Sturtevant, B. F.
ID Number
ER.309240
accession number
89797
catalog number
309240
patent number
100,242

Sturtevant’s Patent Model of a Hot Air Furnace - ca 1869

This model was filed with the application to the U.S. Patent Office for Patent Number 95,281 issued to B. F. Sturtevant of Jamaica Plain, MA on September 28, 1869. Mr. Sturtevant’s patent involved recirculating the air being heated in a room or apartment.
Description
This model was filed with the application to the U.S. Patent Office for Patent Number 95,281 issued to B. F. Sturtevant of Jamaica Plain, MA on September 28, 1869. Mr. Sturtevant’s patent involved recirculating the air being heated in a room or apartment. He had developed improved designs for rotary blowers in the past, initially to provide ventilating air in the work areas of his factory which made wooden pegs for shoes. In this patent he combined the rotary blower, which would be driven by a steam engine, with a heat exchanger through which passed the exhaust steam of the engine. The exhaust steam travelled through the vertical openings shown in the center of the image of the patent model. The air to be heated passed through several horizontal pipes inside the heat exchanger cylinder. The steam heated these pipes which in turn transferred heat to the air. The blower is at the left of the model. Its inlet air came via the return duct at the right after passing through the heat exchanger. Heated air was forced by the blower into the room at the lower left. The inventor claimed his design improved the efficiency of a furnace by continuously reheating the same air. Only a portion of the heat was lost in the room being heated, and a significant energy savings was claimed over heating cold outside air.
Sturtevant was extremely successful with this and his many other patents relating to heating and ventilation. In 1860 he founded the B. F. Sturtevant Co. which was successful and long lived; Westinghouse bought the company in 1945, and operations continued at the Hyde Park, MA factory until its closing in 1989. The company’s equipment was installed in many private and public buildings including the U.S. Capitol and the “New National Museum, Washington, D.C” – now the Smithsonian National Museum of Natural History.
The patent model is constructed of wood and metal. It represents the central duct work, heat exchanger, and rotary blower of Sturtevant’s patent. The air pipes are modelled inside the heat exchanger.
Location
Currently not on view
date made
ca 1869
patent date
1869-09-28
inventor
Sturtevant, B. F.
ID Number
ER.308677
catalog number
308677
accession number
89797
patent number
95,281

White’s Patent Model of a Hot-Air Furnace - ca 1872

This model was filed with the application to the U.S. Patent Office for Patent Number 134,118 issued to Cyrus White of West Roxbury, Massachusetts on December 17, 1872. Mr.
Description
This model was filed with the application to the U.S. Patent Office for Patent Number 134,118 issued to Cyrus White of West Roxbury, Massachusetts on December 17, 1872. Mr. White’s patent was for improvements in the fresh air intake, ductwork, heat exchanger, and flue that would be used in conjunction with an overall furnace apparatus which was not a part of the patent. These components are shown in the accompanying image as upper and lower rectangular chambers interconnected by pipes. The drawings submitted as part of the patent application illustrate how a combustion chamber and a surrounding masonry structure would complete the overall heating installation. The drawings can be found in the patent document online (www.USPTO.gov/patents/process/search/index.jsp). Fresh air entered the lower chamber via an opening on the right side. The cut out area at the left was the access for the combustion chamber which would have been located at the semi-circular metal collar shown above the air chamber. The upper chamber was the heat exchanger, the design of which White claimed as new in his patent. The exhaust gases from the combustion chamber entered via a hole located directly above the semi-circular collar previously mentioned. The exhaust was carried to a chimney through a hole at the right end of the heat exchanger. The hole seen at the left allowed access to the inside for cleaning and would have been closed by a door during operation. The vertical tubes seen in the image carried cold air upwards and through the outer casing of the heat exchanger where the air was heated. The heated air exited where these tubes reemerged from the heat exchanger on the top. White provided for additional heating to take place via smaller pipes that drew cold air from just outside of the heat exchanger. The inlets for these pipes can be seen just above where the larger pipes enter the heat exchanger. The smaller pipes communicated to a small chamber inside the outer heat exchanger case. Air heated in this chamber also exited at the top. White’s patent simply stated that the hot air exiting from the top could be conducted as desired to any apartments of the building. The other features claimed as new in the patent dealt with a set of “jet-holes” which were to be placed in a collar where the combustion chamber exhaust met the heat exchanger. The S-shaped tube seen between the cold air chamber and the heat exchanger provided fresh air to the jets. White claimed the resulting jets of air into the hot exhaust gases caused more complete combustion and better heating. White’s patent design led to the Cyrus White & Company, located in Jamaica Plain, MA. In 1888 it was noted that the company had been successful selling and installing White’s “Tropic” Furnaces.
The patent model is constructed of unpainted tin plate and represents the key elements of the patent as shown in the image and described above.
Location
Currently not on view
date made
ca 1872
patent date
1872-12-17
inventor
White, Cyrus
ID Number
MC.251443
accession number
48890
catalog number
251443
patent number
134,118

Crosby Steam Gauge – ca 1908

This steam gauge was made by the Crosby Steam and Gage & Valve Company of Boston, Massachusetts around 1908. It is 8 ½ inches in diameter and nickel plated.
Description
This steam gauge was made by the Crosby Steam and Gage & Valve Company of Boston, Massachusetts around 1908. It is 8 ½ inches in diameter and nickel plated. The gauge was a gift of the Quincy Mining Company of Hancock, Michigan.
For pressures of less than about one atmosphere (15 pounds per square inch), simple mercury columns were adequate as indicators. With the use of high pressure engines and boilers many types of gauges were introduced. In all of these the pressure of the steam acted against a spring loaded piston or diaphragm to move a pointer.
This is a Bourdon type gauge. This type, one of the first truly successful gauges, was invented in 1849 by Eugene Bourdon of France, a curved tube, elliptical in cross section, was used. When pressurized, the ellipse tended to become more circular, causing a slight straightening of the tube exactly proportional to the pressure. The free end of the tube was linked to the indicating pointer. Bourdon gauges remained in widespread use well into the 20th century.
date made
ca 1908
ID Number
MC.319574
catalog number
319574
accession number
244877
serial number
698575

Ship Model, Schooner Fredonia

This model represents the fishing schooner Fredonia, designed by the well-known yacht designer Edward Burgess of Boston.
Description
This model represents the fishing schooner Fredonia, designed by the well-known yacht designer Edward Burgess of Boston. Burgess designed several America’s Cup racing yachts, including the Puritan, the Mayflower, and the Volunteer, which successfully defended the cup in 1885, 1886, and 1887, respectively. From Burgess’s plans, Moses Adams built the Fredonia in 1889, at Essex, Mass. The schooner measured 111’-6” long, with a beam (width) of 23’-6”, and a depth of 10’-3”. Adams also built the schooner Nellie Dixon from the same plans in East Boston that year.
After launching, the Fredonia was used as a yacht and made a transatlantic cruise before being refitted for work in the offshore fisheries. The vessel became known for its speed, and attracted attention for its fine lines. Its clipper-style bow with carved trail boards led to a long bowsprit (a spar extending forward from the bow that carried the jib). The design influenced fishing schooners for years to come, and vessels built on the Fredonia model came to represent the quintessential New England fishing schooner.
The Fredonia’s influence belied its short life. In 1896 the vessel met with disaster while fishing for cod on the Grand Banks. During a December storm the Fredonia sank, with all but two of its crew of 23 saved by other schooners fishing in the area.
date made
1889
ship built
1889
ship sank
1896-12
designer
Burgess, Edward
shipbuilder
Adams, Moses
ID Number
TR.076253
catalog number
076253
accession number
28022

Evaporating Salt Device Patent Model

This patent model accompanied John Howarth’s patent application that received patent number 117,290 on July 25, The patent describes a process for extracting sulphate of lime (gypsum) from salt brine (concentrated sea water) by evaporating the brine and then superheating it.Curre
Description
This patent model accompanied John Howarth’s patent application that received patent number 117,290 on July 25, The patent describes a process for extracting sulphate of lime (gypsum) from salt brine (concentrated sea water) by evaporating the brine and then superheating it.
Location
Currently not on view
Date made
1871
patent date
1871-07-25
patentee
Howarth, John
inventor
Howarth, John
ID Number
1999.0086.01
catalog number
1999.0086.01
accession number
1999.0086
patent number
117,290

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.