working of the pen.

One of the glass injector nozzles 9 is selected and attached to the small piece of tubing 8 sent loose with the recorder, the other end of the tube being connected to the 1-inch watersupply pipe from the tank. The larger float chamber 55 is filled with pure liquid paraffin (specific gravity 0.86) to the top of the brass clip 24. The paraffin will injure the rubber and must not be spilled on it. In case any has been spilled the tube should be wiped perfectly dry. Then the aluminum float should be inserted carefully, the end of rod 13 being screwed into the socket 11 and locked there by means of nut 12.

The float should not be dented or damaged, and nuts 16 and 17 should be tight. Collar 15 with its lock nut 14 should be brought to about the position shown in figure 6. The smaller float chamber 56 should also be filled with paraffin to the top of clip 25, and the brass float 26 inserted. The cotton thread to which the pen gear is attached should be placed over the pulley 29, and hook 27 fixed to the float. The length of the thread is so adjusted that the float is about onefourth inch from the bottom of the vessel when the pen rests against stop 32. The pen should be given a number of twists away from the chart; the torque will then keep it against the paper. This twisting also shortens the length of the thread, thus raising the float, a detail that must be considered when adjusting the length of the thread. Smooth thread must be used as thread that is the least uneven will cause the pen to make a crooked line owing to jerky movement over the brass wheel 29.

INSTRUCTIONS REGARDING RECORDING PARTS.

In setting up the recording part proper the following instructions should be observed:

Wind the clock, paste one of the charts together and slip it over the clock drums from below, bringing the drums together by moving lever 44 to the right and then letting it slide back gently. Set the chart by sliding it so that the pen points to the time of day. Adjust the length of rod 33 until the point of the pen rests exactly on the 20 per cent line. Fill the container with ink through hole 37. Assist the passage of this to the pen by removing the latter and passing the wire provided through tube 38. Moisten also the lips of the pen with ink. If the line produced is too fine, open the lips very carefully by the use of the fine blade, only sufficiently, however, to be just perceptible. Mix one part of the glycerin accompanying the instrument with three parts of water, and fill vessel 87 nearly full, or to point 95 indicated in figure 6. Dissolve in a strong earthenware or glass jar all the potash sent with the recorder, using 43 ounces of water, preferably distilled. Pour in the water and add the potash gradually, a few sticks at a time, stirring the solution. It becomes

hot while the potash is dissolving and must be allowed to cool before it is poured through funnel 61 into vessel 94. The latter should be filled exactly to the little glass projection 64 on the lower end of the funnel tube. If too much has been added, the excess should be drained off by opening clip 96. The specific gravity of any solution prepared subsequently should be 1.27.

FINAL ADJUSTMENTS.

Instructions as to the final adjustments of the instrument are as follows:

Take out plugs 1 and 2, setting cocks 4 and 6 to cut off the line and let in air. The temperature of the instrument must be that at which it will be operated; if the temperature changes from day to night, the instrument should be set for the average temperature.

Turn on the water through nozzle 9 into tube 74. As the water rises in 82 it will compress the air above the water level and through tube 78. This pressure will act on the liquid in 87, forcing it up tubes 91 and 93. The liquid should rise exactly to zero mark 71 on the neck of measuring tube 67, that mark being reached at the moment when the water in siphon 72 reaches the top and the siphon begins to operate. Should the liquid go higher or lower, adjust the position of siphon 72 after slackening clip 73. Raising the siphon will cause the liquid in 67 to travel higher, and vice versa.

Adjust until the average is at mark 71. In making this adjustment care must be taken not to raise the siphon so high as to force the liquid over through elbow 50 into the potash solution, as that would be spoiled. See that the point of the pen stops exactly at zero on the diagram at the moment the liquid reverses. adjust collar 15; to lower the collar will cause the pen to descend farther, as more of the gas will be apportioned to the brass bell, causing it to rise higher.

If not,

About 30 records per hour can be taken. It is not desirable to exceed this speed as the CO2 will then pass through the KOH too fast, especially when the solution is becoming weak; moreover the liquid piston tends to form more bubbles. Too slow a speed is also undesirable as the liquid forced up from 87 then rises too jerkily, and its levels do not average so well at the time of siphoning. The instrument should be running at the same speed when it is adjusted as when in service.

When adjusting see that, as the liquid rises in 77, no bubble precedes the level, as this will cause the pen to travel down too far. Such bubbles sometimes occur when the glycerin solution gets heavy after some months of use, and the bubbles do not break well at 77. See that 66 is held in place by 75; its action can be checked by seeing that 52 is closed by the rising liquid in 77 at the instant the level in

67 is at the mark 100 on that vessel. Operate for about one hour after all adjustments have been made.

The recorder can now be connected to the gas line. Examine all rubber connections to see that there is no possibility of leakage. Painting all rubber joints and stoppers with asphaltum paint will doubly insure against leakage. In the latest machines the stirrup (43, 45, 46) has been developed into a filter to prevent particles of soot entering the recorder.

The filter is charged with glass wool, which must be taken out occasionally and washed. Wind the clock daily and keep the pen filled with ink. The levels of the different liquids should be watched carefully. The KOH solution forms water in reacting with CO2, so that the level of the solution rises a little each day. The higher level affects the reading, and unless the level is at 64 the recorder will not register correctly. The level should be adjusted daily. Add water to the glycerin solution when it gets low in 87. Keep the paraffin about the bell jars at the same level as when the zero was adjusted.

THE "TELEZOMETER" CO2 RECORDER.

DESCRIPTION OF RECORDER.

INSTRUMENT 4.

The "Telezometer" CO, recorder is described with reference to figures 7 and 8. In figure 7, e and ƒ represent two centrifugal fans driven by the constant-speed electric motor g. Fanf draws in surrounding air through inlet h and forces it out through outlet k; fan e draws in flue gas through inlet pipe m and forces it out through outlet j. There exists, therefore, a difference of pressure between h and k and between m and j. These differences of pressure vary with the density of the fluid medium. As the CO2 component of flue gas is much heavier than any other constituent, the density of the flue gas varies with its CO2 content. Referring to figure 8, the movement of the lever w is caused by the resultant of the four static pressures, m, j, k, and h, acting on the bell jars arranged as shown. The movement of this lever is recorded by the pen t on the clock chart in percentages of CO2.

In figure 8 the bell jars 1, 2, 3, and 4 are represented as floating in separate vessels, whereas in reality 1 and 2 float in one tank and 3 and 4 in another. The regulation of the inlet and outlet pressures of the air fan f is accomplished by means of the pin valve at h, figure 7. Through this regulation the instrument can be adjusted to its zero position when both fans are circulating air. Paraffin oil used in the two tanks is shown at y.

The remaining parts of the apparatus are shown in figure 7, as follows: a, gas filter; o, o', drains from the two tanks in which the

bell jars float; p, p', overflows for these tanks; r, manometer inserted in the line m for special purposes in testing; d, special gage showing the difference of pressure between h and k, used only for testing purposes; n, electric line to motor; c, case containing tanks and recording mechanism; z, lead connecting tubing.

Because of the difficulty of maintaining the necessary operating conditions in service no instructions regarding the erection and operation of this machine are given herein.

Figure 15 shows instrument 4 as installed for the tests.

FIGURE 7.-Arrangement of parts and connections of "Telezometer" CO2 recorder.

The Uehling CO, machine may be explained by reference to figures 9 and 10, in which the letters and numbers correspond. The instrument is really an open pipe line in which pressures (below atmospheric) are measured at different points. The line has been given its present shape for the sake of compactness. If suction is

created by any means at C" (fig. 9), gas will tend to flow through the line, entering at filter D. At manometer M the pressure on the line is measured. The gas passes through valve J, and the pressure is measured again at S. Here it meets an auxilliary suction, C, and tends to divide, the division depending on the relative suctions.

Thence the gas passes through valve 2, through the small cotton filter F, through the steam pot X where it is heated to a constant temperature and then meets a high resistance in the form of the orifice

20

Suction

FIGURE 8.-Arrangement of bell jars and connections, "Telezometer" CO2

recorder.

dicator, and the chart recording gage, each measures pressure. The gas now passes through another small cotton filter F', again through the steam pot X, where it assumes again its original constant temperature, then meets another high resistance at orifice B. Finally it passes through valve 4 out through the suction.

The method of obtaining the suction C and C" can be seen from figure 10. If valves 8 (to let in air), J, 2, and 4 are open and valve 5 is slowly opened, a suction is produced, and atmospheric pressure

FIGURE 9.-Diagram of essential parts of Uehling CO2 machine, arranged as a train.

on the water in H is lowered. As the suction becomes great enough, air flows in through the center tube a and relieves the suction. At the same time air flows in through the line, owing to the suctions C and C". The pressure of the suction is registered by tube v. Now if manometer S is held constant by valve 5, a certain flow of gas is induced through the recording line; and the gas is kept at a constant temperature by being heated at two points just before it passes