REPORT

by scholarship student I. I. Sidorov

for the first half of the 1909–10 academic year

In view of the establishment of a seismic station at the physics laboratory of the Tomsk Technological Institute, I, at the suggestion of Prof. B. P. Weinberg and with the permission of the head of the physics laboratory of the Imperial Academy of Sciences, Academician Prince B. B. Golitsyn, worked during the first half of May in the laboratory of the Academy with seismographs. Under the guidance of the assistants to Prince B. B. Golitsyn, I. I. Vilip and P. P. Nikiforov, I determined the constants of the instrument, selected the damping needed to convert the instrument into an aperiodic one, and worked on the processing of seismograms.

In the middle of May I went to Germany, to the University of Leipzig, where I was able to attend more than half of the summer semester. In physics I attended the lectures of Prof. Wiener (experimental physics, 5 hours per week), while trying, as far as possible, to acquaint myself in detail with the equipment of the Physical Institute, the arrangement of lecture experiments, and the conduct of practical classes. During my stay in Leipzig I attended Prof. Wiener’s course on the theory of heat.

In view of the interest that may be presented by the order of the experiments with which the course in experimental physics is illustrated, I give in Appendix I a list and a brief description of the arrangement of the lecture experiments in the order in which they were shown at the lectures. In Appendix II there is given a list of practical work and the rules for practical students of the Physical Institute of the University of Leipzig.

On arriving in Tomsk in the middle of August, I took part in the acceptance of the physics laboratory of the Technological Institute, in order to acquaint myself with the instruments available in it, and worked on setting up instruments for practical classes.

At the same time I began preparations for the work proposed to me by Prof. B. P. Weinberg, “On the magnetic permeability of gases,” and engaged in the theoretical study of works on seismography, chiefly the works of Prince B. B. Golitsyn.

November 7, 1909.

I. Sidorov.

Appendix I.

Description of the Auditorium for Experimental Physics of the Physical Institute of Leipzig University

The Physical Institute of Leipzig University occupies two interconnected four-story wings, with an area of 2000 square meters: one wing for experimental physics, the other for theoretical physics. The auditorium for experimental physics is about 15 meters wide and 12.5 meters long. The benches are arranged as an amphitheater; the entrance to the auditorium is from above, and three aisles lead downward: one in the middle and two along the walls. The lighting is double: a row of windows along the side walls and a glass ceiling. The side windows have always been closed; the auditorium is darkened by rolling a curtain across the ceiling by means of an electric motor, quite noiselessly. The auditorium has two projection lanterns, which can be used simultaneously: one is placed below, the other above, approximately in the middle of the central aisle; the tables for the projection lanterns can rotate; the screen is the whitewashed wall behind the blackboard; the blackboard is lowered by a motor, which is set in motion by pressing a button placed on the lower frame of the board. To the right of the board, as seen from the exit, there is an exhaust cabinet and a large marble distribution board for the needs of the auditorium. To the left of the board there is a drawer with instruments, a tap, and a water-supply sink. Above the distribution board, on a shelf by the wall, there is a galvanometer, from whose mirror a luminous spot is projected onto a transparent scale descending from the ceiling above the lecture table. The lecture table is about 10 meters long and about 1 meter wide; its middle part is removable. To the table, along its sides, both on the side facing the board and on the side facing the benches, gas, water, a water-drain pipe, a compressed-air pipe, a pipe to the exhaust pump, and electric wires have been brought. All the pipes are painted in different colors; the wires are laid in glass tubes. Compressed and rarefied air is obtained by means of a pump located in the basement story. Above the board there is a small balcony about 0.75 meters wide and 2.5 meters long; gas, water, and electric current are also supplied to the balcony. In the left corner of the auditorium (from the side of the entrance) there is a large stock of all kinds of auxiliary apparatus: various stands, small benches, supports, and so on. The entrance to the preparation room is to the right and left of the board. In the right wall, approximately opposite the end of the table, there is a lifting machine for raising apparatus from the lower stories. Near the right-hand doors into the preparation room hangs a telephone for communication with the entire institute building.

Above the table several blocks are attached to the ceiling. To raise the table, two long reed rods are pulled up to the ceiling on blocks in an oblique direction, from the edges of the board to the side walls. The auditorium has 282 numbered seats and 48 unnumbered seats; the unnumbered seats are folding benches in the aisles at the ends of the benches, the so-called Klappsitze, and behind the last bench, the so-called Reitersitze, since on the latter one must sit astride. Each student, upon enrolling in physics, receives the number of his seat in the auditorium.

List of lecture experiments and a brief description of their setup.

1) Change in the volume of a liquid upon heating.

a) A flask, with a capacity of 1.5 liters, is filled with tallow tinted with dye. A thin glass tube is inserted into it. A cardboard scale is fitted onto the tube. Heating was carried out by hand.

b) The same with alcohol. Heating was carried out with a gas burner.

c) The same with water. Heating—with the same burner.

2) Change in the volume of solid bodies upon heating.

A metal ring and a ball freely passing through it at the same temperature as the ring.

3) Change in the length of solid bodies with a change in temperature.

a) Disturbance of the equilibrium of scales when one arm is heated.

b) Different elongation of zinc and iron rods when heated; the elongation was marked on a screen by a light spot from mirrors attached to levers against which the rods pressed.

c) A plate made of copper and iron rods riveted together bent when heated.

d) Shortening of rubber when heated.

A rubber tube, about 2 meters long, suspended from a balcony, was stretched by a load to approximately 1 meter; then steam from a kettle placed on the balcony was passed through it. A pointer at the end of the rubber tube slid along a vertical scale placed on the lecture table.

4) Forces developing in a solid body when it expands or contracts with a change in temperature.

a) Trevelyan’s apparatus.

A brass triangular prism, having a groove along one of its edges, is strongly heated and placed groove downward on a lead horizontal cylinder, and after a lateral push begins to oscillate rapidly, producing a rather high sound.

b) Tyndall’s apparatus.

An iron rod, shortening upon cooling, breaks a cast-iron rod perpendicular to its length and resting on two supports.

5) Change of the volume of a gas upon heating.

A U-shaped tube, each limb of which was about 2.5 meters, was filled with colored alcohol; one end of it was open, the other was connected, by means of a capillary brass tube, with a brass vessel. The latter was immersed in turn in melting ice and in the steam of boiling water, and, according to the position of the levels in the open limb, a scale was marked. In subsequent experiments this apparatus was often used for measuring temperatures.

6) Change of the pressure of a gas.

A round-bottomed flask with a drawn-out narrow tube was heated on a gas burner, after which the tube was lowered into a cup with mercury. The mercury beat into the flask in a little fountain.

7) Change of the density of a liquid upon heating.

a) A small flask with a small quantity of mercury was balanced on hydrostatic scales in cold water; when the cold water was replaced by hot water, the equilibrium was disturbed.

b) A U-shaped glass tube, the length of each limb about 2 meters and the diameter 15 millimeters, was filled two-thirds with colored kerosene. One limb was inserted into a wider tube, through which steam from boiling water was passed. After steam had been passed for 3–5 minutes, the difference of the levels became very noticeable.

c) A metal ball, sinking in hot water and floating in cold water.

d) A glass vessel of such a form, about 25 cm wide and 30 cm high, is heated from the side by a gas burner; grains of aniline dye are dropped into the upper opening. The current of the heated liquid becomes visible.

8) Change of the density of a gas.

A glass tube, 1.5 meters long and 5 cm in diameter, hangs vertically; both ends are open. Beneath it stands a gas burner with a nozzle having the form of a double hollow cylinder. A ball of asbestos wool is introduced with tongs through the side opening of the burner into its cylindrical part and flies through the glass tube, carried by the current of hot air.

9) Determination of the coefficient of thermal expansion of air.

A thin glass tube with a bulb, of capacity about 5 cubic cm; its other end is open. Marks are made on the tube, giving at once the volume of air in the bulb and in the tube up to the given mark. The air is confined in the tube by a drop of mercury. To heat the air, the thin tube is placed in a wide glass tube through which steam from boiling water is passed. The coefficient was determined from the volumes at room temperature and at the temperature of boiling water.

10) Determination of the thermal coefficient of gas pressure.
An air thermometer, 2 meters high; a glass vessel of 100 cubic centimeters capacity was connected immovably to a manometric tube by means of a glass capillary tube. To determine the coefficient, the pressure was read when the vessel was immersed in melting ice and in the vapor of boiling water. Vessels with melting ice and with the vapor of boiling water were suspended beneath the glass vessel of the thermometer on a special stand.

11) Determination of the mixing temperature.
Two equal quantities of water at zero temperature and at a temperature close to the boiling point were mixed; these temperatures and the temperature of the mixture were determined by means of the air thermometer described above.

12) Heat capacity.
A thermoscope of the Looser type, of large dimensions, about 2 meters high. Toluene and water, in equal weight quantities, were heated in glass beakers in the vapor of boiling water and simultaneously poured into the vessels of the thermoscope.

13) Cooling during evaporation.
a) A batiste cover was put on the glass vessel of the air thermometer; once the cover was doused with ether, another time with water.

b) On a wooden cube, moistened with water, a small saucer filled with ether was placed; to intensify the evaporation of the ether, a stream of air was directed onto it. When all the ether had evaporated, the little cup proved to be frozen to the cube.

14) Heating by friction.
A metal tube, filled with ether and tightly closed with a stopper, was screwed to a centrifugal machine driven by an electric motor and was clamped between two wooden plates. The heating caused the ether to boil and the stopper to fly out.

15) Heating by impact.
A lead plate, weighing about 500 grams, was raised by a pulley to the ceiling and from there fell freely. The raising and releasing was carried out three times, after which its temperature was measured with a thermoelectric pair.

16) Heating of mercury when pouring it.
About one kilogram of mercury was poured from a cup into a cup from a height of approximately one meter 25 times; the temperature was measured with a thermoelectric pair.

17) Heating by compression.
A small wooden plate was compressed three times in succession under a hydraulic press. The temperature was measured with a thermoelectric pair.

18) Heating of iron by impact.

Heating of iron by impact.

An iron nail was subjected to several blows of a hammer. The heating was measured as in the preceding experiment.

19) Heating of a gas under compression.

An air lighter of the usual type and size.

20) Cooling of a gas upon rapid expansion.

The experiment of Clement and Desormes with a round-bottomed flask of about 1.5 liters capacity.

21) Illustration of the fact that the pressure of a gas is the result of impacts, against the walls of a vessel, of the moving particles of the gas.

A wooden polished slide, slightly concave (like ice slides), about a meter long, its inclination about \(45^\circ\); at a short distance from the lower end of the slide a plate was placed, connected by a lever to a pointer indicating the force of the impact on the plate. Between the end of the slide and the plate a small space is necessary, into which the balls could fall after striking the plate. To the upper part of the slide four tubes are attached, with lateral openings at the beginning of the slide; the tubes are filled with wooden balls. By pistons moving uniformly in the tubes from below by means of an electric motor, the balls are driven out of the tubes onto the slide: in this way a series is obtained of very frequent impacts, delivered at equal intervals on the plate; the pointer departs from the position of equilibrium and remains—of course, oscillating all the time—in a certain deflected position. When the action of the motor is strengthened, the deflection of the pointer increases, since the number of impacts per unit time increases.

22) Elasticity of liquid vapor.

a) A round-bottomed flask, of about one liter capacity, with a thin tube drawn out at the end into a capillary; several drops of liquid have been poured into it. When the flask is immersed in boiling water, the liquid turns into vapor; then the drawn-out end of the tube is sealed; the flask is cooled, the end of the tube is immersed under water and there broken off; the water pours strongly into the flask.

b) A glass tube, 15 millimeters in diameter and about 760 millimeters high, sealed at one end, is filled with mercury and immersed with its open end in a mercury bath. A thin-walled glass bulb is filled with ether and, sealed, is introduced under the mercury into the tube; it strikes the sealed end of the tube and breaks; the ether vapor formed greatly lowers the level of the mercury.

23) Diffusion of gases through porous partitions.

The usual apparatus with a porous vessel attached to a tube passing through one of the necks of a two-necked bottle.

24) Friction in air.

A wooden disk about 45 cm in diameter was attached to a centrifugal machine; above it, at a distance of 2 cm, a mica disk 38 cm in diameter was suspended horizontally on a thread about 2 meters long. The centrifugal machine was set in motion by hand; the mica disk then also began to rotate; so that its rotation could be seen from afar, a small flag was attached to it.

25) Friction in a liquid.

A large beaker, 30 cm high and 35 cm in diameter, is filled with water, on the surface of which two corks float. At a distance of 5 cm from the water level a metal disk 30 cm in diameter is placed; the disk is rotated about its axis by hand; after a little while the corks also begin to rotate.

26) The velocity of the outflow of gases from the opening of a capillary tube.

A glass jar, with a capacity of 1.5 liters, has three openings; into two openings capillary tubes of various diameters, with stopcocks, are inserted; the third opening is connected with a U-shaped tube 2 meters high; by pouring water into the other opening of this tube, one can compress the air in the glass vessel. By opening the stopcock of one or the other tube and observing the rate at which the water descends in the U-shaped tube, one can clearly see the different rates at which air flows out of the vessel.

27) Thermal conductivity of gases.

a) Both reservoirs of the thermoscope were placed in glass vessels; one vessel is filled with hydrogen, the other with air. These vessels, in turn, were immersed in boiling water. The difference in the levels of the liquid in the thermoscope proved to be very sharp.

b) Into a glass tube, about 0.75 meter long and 5 cm in diameter, divided into two parts by a glass partition, a platinum wire is fused. One half of the tube is filled with air, the other with hydrogen. When current is passed, the wire becomes incandescent in air and does not become incandescent in hydrogen.

28) Direct diffusion of gases.

Two beakers, 30 cm high and 10 cm in diameter, are filled with hydrogen and air; the first of them is inverted and placed over the other; after a short time, in both beakers the mixture of gases ignites, producing an explosion.

29) Free diffusion of liquids.

A luminous slit, inclined at an angle of 45° to the horizon, passing through a column of liquid in which diffusion is taking place, is projected onto a screen. From the curvature of the image of the slit on the screen, one can judge the course of diffusion. (I note that this is one of the few experiments in which Prof. Wiener resorted to a projection lantern.)

30) Diffusion of a liquid through a porous partition.

A cup with water; into it a glass vessel is immersed, into the top of which a horizontal glass tube is inserted; the vessel is filled ...

with alcohol; the bottom of the vessel is a bladder. From the movement of the alcohol in the horizontal tube one can judge the course of diffusion.

31) Isotonic solutions.

Into a vessel with plane-parallel walls and filled with a solution of copper sulfate, drops of a solution of potassium ferrocyanide are introduced. The drop is immediately covered with a membrane, and from the appearance and direction of the streams from the membrane into the copper sulfate one can judge the isotonicity and the relative concentration of the solutions. The image of the drops is projected.

32) Dissolution of ammonia in water.

A flask, of about 1.5 liters capacity, is filled with ammonia; a glass tube, drawn out and sealed, is inserted into it. This end of the tube is immersed in a cup of water and broken off there: the water spurts like a fountain into the flask.

33) Boiling under reduced pressure.

a) The usual experiment with a cup of water under the bell jar of an air pump.

b) The usual experiment with a flask of water, corked during boiling and inverted.

34) Freezing of water during its rapid evaporation.

Air is pumped out of a vessel with water by means of a pump; between the vessel and the pump two vessels with sulfuric acid are placed.

35) Change of melting temperature with pressure.

Pieces of ice are pressed into a solid piece in a metal mold by a hydraulic press.

36) Change in the volume of water upon freezing.

Rupture of a cast-iron vessel by water when it is frozen with a cooling mixture.

37) Daniell, Assmann, August, and Lambrecht hygrometers.

The humidity of the air in the auditorium was determined with the Lambrecht hygrometer. The wall of the vessel on which dew appeared was projected onto a screen by reflected light.

38) Cryophorus.

39) Deposition of water vapor from the air when it is cooled.

On scales a glass with ice is balanced; after some time the equilibrium is disturbed: the cup with ice descends.

40) Liquefaction of vapor when it is compressed.

A wide glass tube, one meter long and about 3 cm in diameter, stands vertically; one end is sealed, the other ends in a funnel; mercury is poured into it, and another glass tube, sealed at one end, about 1.75 meters long and of smaller diameter, partly filled with vapor and partly with mercury, is inserted with its open end into the mercury. By immersing such a tube more or less deeply in the mercury, we can cause the ether vapors either to be compressed or to expand.

Report for the First Half of the 1909–10 Academic Year

41) Different elasticity of different vapors.

Four barometric tubes with a vacuum of about 10 cm. Water, alcohol, and ether are introduced with a pipette into three tubes; the fourth remains as a control.

42) Influence of temperature on the compression of a gas.

A tube filled with carbon dioxide gas is projected onto a screen. The gas in it is compressed by a column of mercury forced into it. At first the tube was cooled by pouring ether over it; the gas was compressed and liquefied; then the pressure was reduced, and the liquid passed into the gaseous state. After this the tube was warmed slightly; the gas was compressed to the same pressure as the first time, but liquefaction did not occur; as soon as the gas was cooled, liquefaction took place.

43) Critical temperature.

A sealed tube with ether.

44) Solid carbonic acid.

The temperature of a mixture of it and ether was determined with an air thermometer. Prof. Wiener took a piece of solid carbonic acid into his mouth and extinguished a candle with a stream of carbonic acid.

45) Liquid air.

Its temperature was determined with an air thermometer. Living flowers were frozen.

Appendix II.

Rules for Practicum Students at the Physical Institute of Leipzig University, 1908

1) The preliminary condition for attending practical exercises is a thorough knowledge of the laws that must be used in making measurements. Therefore it is generally recommended that the practicum student have attended at least one semester of experimental physics. With especially good preparation, work may be begun, with the permission of the director of the institute, already in the first semester.

It is assumed that the practicum student is sufficiently familiar both with the theory of the problems assigned to him and with the handling of the necessary instruments. For preliminary preparation and for use during the exercises, Kohlrausch’s Short Guide to Practical Exercises in Physics is recommended—or, for those who wish to become more thoroughly acquainted with methods of measurement, the Textbook of Practical Physics by the same author.

3) Before leaving, the practicum student informs the assistant in charge of the exercises whether he has finished his work or not. The assistant, in turn, tells him what problems will be assigned to him the next time.

4) Every measurement must be repeated at the request of the director or the assistant.

5) The practicum student must have, for recording his work, an observation notebook intended solely for this purpose. In this notebook, the observations of each day’s work are entered in a clear form under the date of that day, together with a statement of the problem.

6) This notebook must be with him on every day of exercises; otherwise the practicum student has no right to make claims for receiving new work.

7) The results of observations, if they can be counted off directly, or if their calculation requires little time, are reported to the assistant on the day of the work. In the case of more complicated calculations, the result is presented on the next working day.

8) Since the set of weights for the scales contains no fractions of a gram, the practicum student is issued, against a deposit of 3 marks, a box with such fractional weights and, together with it, the key to the lockable drawer. At the end of the semester, upon return of the fractional weights and the key, the deposit is fully returned. For damaged or bent fractional weights, their cost is withheld. The key and the fractional weights must be returned on the last working day; otherwise, at the expense of the deposited sum, the lock will be opened and a new key will be made.

9) The trainee is obliged to return the apparatus issued to him to its place, intact and well cleaned.

10) Auxiliary apparatus, such as: tripods, wooden stands, gas burners, lamps, rubber tubing, glass vessels, electric wires, clamping screws, etc., after use must immediately be returned to their place in a neat condition, so that they can be used again at once.

11) All apparatus, and especially balances and weights, must be handled with the greatest care. Weights must not be taken by hand, but only with tweezers; they must not be placed on the table, and they must be removed from, or placed on, only arrested balances. After use, the weights are put back in strict order. The arresting device must be operated slowly. It is most strictly forbidden to leave the balances loaded, not arrested, or with the glass case open.

12) Any damage to an instrument or auxiliary apparatus, as well as any loss of weights, must be reported immediately to the assistant in charge of the exercises.

13) It is forbidden to throw any kind of refuse, such as scraps of paper, matches, etc., onto the table, onto the floor, or into the sink; they must be immediately placed in the vessels assigned for this purpose.

14) It is forbidden to leave gas or alcohol burners burning unnecessarily, as well as lamps for illuminating scales.

15) One should try to avoid spilling mercury, acids, alkalis, solutions of salts, alcohol, and ether.

16) For every broken or damaged instrument or auxiliary apparatus a fine of 20 pf. is imposed.

17) Each violation of the rules §§ 9–15 entails a fine of 20 pf.

18) Fine money goes toward supplementing the institute library.

List of Problems in General Physics Practicum

Measurement of length by means of a vernier caliper, a micrometer screw, and a spherometer.

The same with a cathetometer.

The barometer and measurement of height.

Atwood’s machine.

Determination of \(g\) by means of a pendulum.

Exercise on a model of balances.

Weighing by observation of oscillations.

Absolute double weighing and determination of the error of balances.

Checking the weights.

Density of solids from mass and volume.
The same by hydrostatic weighing.
The same with a pycnometer.
The same with Jolly’s balance.
Density of liquids with a pycnometer.
The same on Mohr’s balance.
The same with a hydrometer (communicating tubes).
Density of vapor by Dumas’s method.
The same by Victor Meyer’s method.
The same by Hofmann’s method.
Density of a gas.
Density of air by weighing.
Analysis of air with a eudiometer.

Determination of the elastic constant from the stretching of wires.
The same from the bending of rods.
The same from torsional oscillations.

Determination of the number of vibrations of a tuning fork by means of an interference apparatus.
Determination of the number of vibrations of a tuning fork from a record on a soot-covered drum.
Determination of the speed of sound from Kundt’s dust figures.

Checking the fixed points of a thermometer.
Comparison of two thermometers.
Melting point of solids.
Solidification point of an alloy.
Determination of molecular weight by depression of the freezing point.
The same by elevation of the boiling point.
Determination of the humidity of air by the appearance of the dew point, by a psychrometer, and by a hair hygrometer.
Thermal expansion of rods.
The same of glass and liquids with Sprengel’s pycnometer.
Air thermometer.
Determination of the heat capacity of solids by the method of mixtures.
Determination of the heat capacity of solids with an ice calorimeter.
The same of liquids by the immersion method.
Determination of the heat of solution and neutralization.
Determination of the thermal conductivity of liquids.
Determination of the mechanical equivalent of heat.

Capillary constant.
Measurement of the internal friction of liquids.

Comparison of light intensities with the Lummer–Brodhun photometer.
Measurement of the angle of a crystal with the Wollaston goniometer.
Determination of the focal length of a converging lens.
The same for a concave mirror.
The same for a diverging lens.
Determination of the radius of curvature of a converging lens.
The same for a concave mirror.
The same for a diverging lens.
Determination of the magnification of a loupe, a microscope, and a telescope.
Measurement on a model of a spectrometer.
Determination of the refractive index by means of a spectrometer.
Determination of the wavelength of light by means of a grating.
Determination of the refractive index by means of Abbe’s refractometer.
The same by means of Pulfrich’s refractometer.
Spectral analysis (emission and absorption spectra).
Determination of the angle of polarization of a glass plate.
Rotation of the plane of polarization in quartz.
The same in a sugar solution (determination of the quantity of sugar in the solution).
Exercise on Nöremberg’s polarization apparatus.
Measurement of the angle of the axes in a biaxial crystal.

Determination of the resistance of a wire by substitution.
Measurement of resistances with a Wheatstone bridge.
Determination of resistance from the damping of a magnet.
The same by means of a magnetic inductor.
Determination of resistances with a differential galvanometer.
Determination of the resistance of wires by branching.
Determination of the specific resistance of a salt solution by substitution.
Determination of the resistance of electrolytes according to Kohlrausch.

Comparison of electromotive forces by the compensation method.
Work with a thermoelement.
Absolute measurement of electromotive forces by the compensation method according to Poggendorff.
Verification of Faraday’s electrolytic laws.
Graduation of a tangent compass by means of a silver voltmeter and calculation of the horizontal component.
Determination of the reduction factor of a galvanometer.
Work with an electrometer.
Distribution of magnetism in a magnet.
Determination of inclination with an earth inductor.
Determination of the horizontal component of terrestrial magnetism according to Gauss.

Comparison of the horizontal component at various places with Kohlrausch’s local variometer.

Measurement of the coefficient of self-induction with a Wheatstone bridge.

The same, of capacitance.

Measurement of capacitance with a ballistic galvanometer.

Determination of the dielectric constant by means of electric waves, according to Drude.

Measurements with G. Holtz’s thermopile.

Measurements of current strength and measurements on a dynamo.

List of problems for physicians and pharmacists

Measurement of length by means of a caliper, a micrometer screw, and a spherometer.

Barometer.

Exercises on a model of scales.

Density of solids from mass and volume.

The same, by hydrostatic weighing.

Density of liquids with a pycnometer.

The same, on Mohr’s balances.

The same, with an areometer.

The same, with a hydrometer.

Determination of the density of vapor by Victor Meyer’s method.

Analysis of air with an eudiometer.

Determination of the number of vibrations of a tuning fork from a record on a smoked drum.

Calibration of the fixed points of a thermometer.

Checking a medical thermometer.

Boiling point of liquids.

Determination of the humidity of air by the appearance of the dew point, with a psychrometer, and with a hair hygrometer.

Measurement with an air thermometer.

Determination of the heat capacity of solids by the method of mixtures.

Determination of the mechanical equivalent of heat.

Measurement of internal friction in liquids.

Comparison of luminous intensities with a Lummer–Brodhun photometer.

Determination of the focal length of a converging lens.

The same, of a concave mirror.

The same, of a diverging lens.

Determination of the radius of curvature of a converging lens.

Determination of the magnification of a loupe and a microscope.

Measurements on a model of a microscope.

Determination of the refractive index by total internal reflection.

Spectral analysis (emission and absorption spectra).

Rotation of the plane of polarization in a sugar solution (determination of the amount of sugar in the solution).

Determination of the resistance of wires by the substitution method.

Measurement of resistances with a Wheatstone bridge.

Determination of the resistance of electrolytes and of the human body by Kohlrausch’s method.

Comparison of electromotive forces in circuits of high resistance.

Verification of Faraday’s laws of electrolysis.

Calibration of a tangent galvanometer with a silver voltameter.

Measurements with Pohl’s thermopile.