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the sensitivity of the reaction appears, in spite of the more dilute reagent, t o be slightly greater in the octyl alcohol solution. From a series of experiments i t was found that when 1 or 2 ml. of a saturated solution of ammonium stearate in 2ethylhexanol was added t o like volumes of a solution of lithium chloride in this same solvent, a slight but definite reaction was still obtained when the amount of lithium present was as low as 0.01 to 0.02 mg.
Summary These experiments show that 2-ethylhexanol yields results equal t o or better than those obtained b y the use of isoamyl alcohol with the advantage t h a t no solubility corrections are necessary and therefore no attention need be paid to the exa c t volume of solvent used in the extraction or for washing. Another advantage of 2-ethylhexanol over isoamyl alcohol for this separation is t h a t the former need not be boiled in order to dehydrate the salts properly. As a consequence the
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danger of loss from bumping is less, and quantities of disagreeable fumes are not evolved, which some chemists regard as a serious objection to the isoamyl alcohol method of Gooch. On the whole, 2-ethylhexanol appears to be the best solvent yet proposed for the separation of lithium from potassium and sodium by extraction of the mixed alkali chlorides. The ammonium stearate reaction for the detection or estimation of lithium may be applied with at least equal success in 2-ethylhexanol solution.
Literature Cited Caley, J . Am. Chem. Soc., 52, 2754 (1930). Gooch, Proc. Am. Amd. Arts Sci., 22, 177 (1886). (3) Kahlenberg and Krauskopf, J . Am. Chem. SOC.,30, 1104 (1) (2)
(1908).
(4) Turner and Bissett, J . Chem. Soc., 103, 1904 (1913). PREBEHTED before the Division of Analytical and Micro Chemistry at the CHEMICAL SOCIETY, Atlantic City, N. J. 102nd Meeting of the AMERICAN Constructed from a senior thesis submitted b y Herbert D . Axilrod to the Department of Chemistry, Princeton University, 1941.
Improved Manometer Design W. G. SMALL AND A. F. G . DRAKE Instrument Division, Consolidated Mining and Smelting Company of Canada, Ltd., Trall, B. C.
I
N CHEMICAL and metallurgical plants there are numer-
ous applications for vertical manometers, t o indicate pressure, vacuum, liquid level, or fluid flow rate. The diagram illustrates a manometer that can be made in any plant having ordinary machine shop and welding facilities. It is inexpensive, can be made in any length desired, is easily maintained, and will not lose any appreciable amount of manometer liquid even when pressures greatly in excess of the maximum scale reading are accidentally applied. The body of the manometer consists of two pieces of standard l'/*-inch wrought iron pipe separated by a 1.56-cm. (0.625-inch) mild steel partition to which they are welded. A length of standard '/,-inch wrou ht iron pipe is inserted through a central hole in the partition fate and welded to it. This tube extends 6.25 cm. (2.5 inchese above the plate and down to a point 1.25 cm. (0.5 inch) above the bottom outlet hole to the gage glass. The top outlet hole to the gage glass is drilled so that the bottom of this hole is flush with the top of the partition plate. Bosses are welded to the sides of the manometer body and are drilled and tapped for the high- and low-pressure connections and the filling plug. The high- and low-pressure connections can be spaced for convenient installation of an equalizing valve. The open ends of the meter body are closed by welding on end plates, which are drilled and tapped for '/a-inch pipe plugs for ease of cleaning and draining. A 0.16-cm. (0.0625-inch) thick mild steel baffle plate is welded to the top end plate before it is put in place. The end blocks for the gage glass are drilled and tapped m shown for the gland nuts and clean-out plugs, and welded to the manometer body. Care must be taken to hold these blocks rigidly in correct alignment where they are being welded in place, as gage glasses are easily broken by tightening up incorrectly aligned gland nuts. A satisfactory gage glass is Pyrex tubing of 3-mm. bore and 3.5-mm. wall. An aluminum or plastic scale with zero adjustment is mounted behind the gage glass. In this type of manometer a correction must be made on the scale for the depression of the liquid level in the high-pressure chamber. In the manometer described above the correction factor is 0.94. OPERATIOK.When a pressure in excess of the maximum scale reading is applied, the liquid seal in the lower chamber is broken at the bottom of the central tube. The manometer liquid in this tube is blown into the upper chamber, where it collects in the annular space surrounding the tube. The baffle plate prevents this liquid from being blown out of the manometer. The central tube is then free of liquid, and permits continued passage of gas with no further disturbance of the liquid. When the excess pressure is released, the liquid in the up er chamber drains back to the lower chamber through the gage gkss and restores the seal.
This type of manometer is particularly suitable for use in chemical plants on materials with high crystallizing temperatures, as the body of the instrument can readily be maintained at a temperature above the point of crystallization b y means of a steam jacket or electric heater. w Pressure Conne e tion
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