The Apparatus of Alfred P. Gage
Thomas B. Greenslade, Jr.
Kenyon College, Gambier, Ohio 43022
Alfred P. Gage (1836-1903) was the author of five textbooks on introductory physics in the last twenty years of the nineteenth century. To supplement his books, he produced a line of apparatus for the newly-emerging high school physics laboratory. Over the past forty years I have been tracking Gage apparatus, and have turned up only eight of these pieces of apparatus out of about 3500 that I have photographed.
From telegrapgh sounder to electric motors
Alfred Payson Gage (1836-1903) graduated with honors from Dartmouth College and shortly before the start of the Civil War established an academy in the town of Laurinburg, North Carolina. After he returned north in 1864, he taught in schools in the Boston area, and in 1874 became a master at the English High School in Boston, where he taught until shortly before his death. There his assignment was to teach drawing and physics. 1
The impetus for this paper came when I started to examine the small telegraph sounder in Fig. 1. This seemed to be a rather ordinary piece of apparatus, apart from its small size (about 12 cm long) and rather attractive curved pillar. However, when I removed a label between the binding posts, Gage’s mark appeared and there was great elation in the Greenslade house!
Soon afterward I looked more closely at what I thought was an 1891 catalogue of apparatus sold by the Ziegler Electric Co. of Boston, and realized that it was really a Gage catalogue, with the Gage name over stamped with Ziegler’s name. At the beginning of the catalogue is the following Partnership Notice. “To my patrons: When, in 1882, I embarked in this business, it was to meet what seemed to be at least a temporary demand for apparatus less expensive in finish, more comprehensive in scope, and such as can be manipulated by pupils with greater impunity than the apparatus then in general use. Subsequent rapidly increasing sales and almost world-wide dissemination of this class of apparatus – ample testimony to the wisdom of the undertaking – have led me to decide to place my business on a more permanent basis. In furtherance of this intention, I have this day admitted as a legal partner in business my son, Sewell J. Gage. His training in the laboratory of the English High School in this city, and his experience as an assistant in my warerooms, render him particularly well fitted to carry on a business in which I shall in future act chiefly as an advisor and designer. Very sincerely, ALFRED P. GAGE, Boston, January 1, 1891.”
At the beginning of the Electricity and Magnetism section of his catalogue, Gage wrote, “The days of making a plaything of electricity are past. Put money into galvanometers, resistance-coils, and articles of utility, rather than into electrical toys, such as the larger portion of frictional (i.e., electrostatic) apparatus.” His galvanometer must have been one of his best-sellers, for I have located three of them, including the one in my own collection in Fig. 2. This is an astatic galvanometer that can be used in any orientation with respect to the horizontal component of the magnetic field of the use. There are two magnetic needles hung from the [broken] suspension, with the north pole of one placed about the south pole of the other. This combination thus has no net magnetic moment and has no preferred orientation. If you look closely, you can see that the lower needle is placed inside the current-carrying coil, and only this one responds to the current.
I have discovered that modern-day physics students no longer learn about the Wheatstone bridge. If they want to measure a resistance, they turn to a solid-state multimeter, set it to “OHMS” and have their answer without resorting to the tedious balancing operations that I learned in my academic youth. However, the design is useful for teaching circuit analysis, especially when the instrument is laid out in the classic diamond-shaped design like the one in Fig. 3. In this example at Hampden-Sydney College in Virginia, the galvanometer is connected across the open space in the middle of the circuit, with the tap key that puts the galvanometer into the circuit just to its left. The tap key at the bottom puts the battery into the circuit. The three coils on either side are 1 Ω, 10 Ω and 100 Ω, which allows the ratio arms to have multipliers from 0.01 to 100. The unknown and the resistance box are connected across the two remaining gaps in the circuit. Fig. 4 is drawn from Gage’s “Introduction to Physical Science”, with this comment that the figure “represents a prospective view of the bridge (as modified by the author)”. 2
The resistance box itself is shown in Fig. 5. The design of this instrument is somewhat strange, with three decades being laid out in a circle. The text accompanying the woodcut (Fig. 6) in “Introduction to Physical Science” 3 tells us that “when the three switches rest on the studs marked 0, the current meets no appreciable resistance in passing through the box, but any desired resistance within the range of the instrument can be obtained introduced by moving the switches on to the studs, the sum of whose resistances is the resistance required. The instrument is called a rheostat.” In my collection I have an example of the same device made by Olmsted of Chicago, and Fig. 7 shows the underside. The resistance segments are lengths of wire, and as the switch arms are moved along the studs, more lengths of wire are included.
This instrument was also used to find resistances using a simple substitution method. Wire up a series circuit with a galvanometer, the unknown resistance and a source of EMF. Note the reading of the galvanometer, replace the unknown with the resistance box and adjust it until the galvanometer has the same reading. This technique was suggested in 1843 by Wheatstone in his Bakerian lecture in which he also mentions the bridge design that he borrowed from S.H. Christie.
The Magneto-Electric Machine in Fig. 8 is based on a design by Joseph Saxton (1799-1873) in 1833. The coils of wire are rotated rapidly in the field produced by the U-magnet, formed of four pieces of steel riveted together, and the resulting voltage can give you a brisk shock. This would seem old-fashioned, but Gage was interested in using small, hand-cranked generators to replace batteries.
Michael Faraday’s discovery of induced EMFs in 1831 led to the development of the transformer, in which the primary coil, with a small number of turns, is placed inside a secondary with a great many turns of fine wire. The key point in Faraday’s circuit is that changing the state of the current in the primary – making or breaking the direct-current signal applied to it – produces an EMF in the secondary. The induction coil 4 has primary and secondary coils fixed relative to each other, and a device for interrupting the primary circuit. In the pair of separable helices in Fig. 9 this device is a small electromagnet through which the primary current passes. When the device is started up, the magnet pulls down the spring steel reed above
it, breaking the circuit. The reed then springs back, the circuit is reestablished and the cycle repeats. The instrument in Fig. 10, which is essentially the same as the previous one, is by Gage, but has lost its interrupter over the years. When I use instruments like this in a demonstration, I start out with nothing in the hollow core, and the output signal is weak. Then I place a brass rod that has been chrome-plated into the core, and the signal is only slightly larger. This upsets the students, who expect that a rod that looks like steel should have a big effect. However, using a solid steel rod makes them feel better.
All apparatus makers sold balances of various types, and many of them were made by the Fairbanks Scales Manufacturing Co, founded in 1830 in St. Johnsbury, Vermont. The example in Fig. 11 that I photographed at the Virginia Military Institute is listed as a “Harvard” trip balance at $5.75.
The direct-current electric motor, shown in Fig. 12, sits atop a pedestal. This is the clue that tells us that the motor was designed to spin a lit Geissler tube in a circle. The set-up is shown in Fig. 13, from “Introduction to Physical Science”. 5 Two batteries are required: one to power the motor, and another to run the small Ruhmkorff coil that supplies the high voltage to excite the gases in the discharge tube. Here Gage is referring to the form of induction coil that was made popular in the latter part of the 19th century by the Parisian apparatus maker Heinrich David Ruhmkorff.
There are certainly more pieces of Gage apparatus out there. The historical apparatus community is primarily focused on college and university holdings, and not on the secondary schools where most of his apparatus must have been sold. In particular, the older independent schools in the northeastern part of the United States certainly contain other examples of Gage apparatus, and I would be interested in hearing from teachers in those schools.
- Rufus P. Williams, “Alfred Payson Gage”, School Science, 3 (1903), pp. 49-52. ↩
- Alfred P. Gage, Introduction to Physical Science (Boston: Ginn & Company), 1891, p. 180. ↩
- Op. cit. Ref. 2, p. 179. ↩
- Thomas B. Greenslade, Jr., “The Induction Coil”, eRittenhouse, 25 (2014), pp. 1-12. ↩
- Op. cit. Ref. 2, p. 204. ↩