Forceps

For the filtration of very small quantities of crystals, the simple apparatus shown in Fig. 46 is often used. It consists of a fine glass rod (sometimes termed a filtration nail ) which is flattened at one end, the flattened surface being preferably roughened. It fits as shown into a small funnel which replaces F (Fig. 45). A circular piece of filter-paper is cut e-g.y with a clean sharp cork-borer) so as to fit completely and snugly over the flat end. After draining, the nail is raised and the filter-paper and crystals are removed with forceps and dried. 

When three consistent readings are obtained, add a weighed pellet of the solute to T for this purpose it is important that the thermometer is not withdrawn, and the boiling is not interrupted. It is best to hold the pellet ready in a pair of forceps near the mouth of the side-arm of T, and then momentarily to remove the condenser, drop in the pellet and replace the condenser when the condenser is removed a small quantity of cold air entering the side-arm will cause slight condensation of the hot vapour, none of which will therefore escape. 

Prepare a saturated solution of sodium sulphide, preferably from the fused technical sodium polysulphide, and saturate it with sulphur the sulphur content should approximate to that of sodium tetrasulphide. To 50 ml. of the saturated sodium tetrasulphide solution contained in a 500 ml. round-bottomed flask provided with a reflux condenser, add 12 -5 ml. of ethylene dichloride, followed by 1 g. of magnesium oxide to act as catalyst. Heat the mixture until the ethylene dichloride commences to reflux and remove the flame. An exothermic reaction sets in and small particles of Thiokol are formed at the interface between the tetrasulphide solution and the ethylene chloride these float to the surface, agglomerate, and then sink to the bottom of the flask. Decant the hquid, and wash the sohd several times with water. Remove the Thiokol with forceps or tongs and test its rubber-like properties (stretching, etc.). 

Delicate forceps, needles, thread, scissors, and safety pins. 

Sodium on the skin. If a small solidified fragment of sodium can still be seen, remove it carefully with forceps. Wash thoroughly with water, then with 1 per cent, acetic acid, and finally cover with gauze soaked in olive oil or acriflavine jelly. 

Glass in the eye. Remove loose glass very gerUly with forceps or by washing with water in an eye bath. Call for a doctor immediately. 

It is very poisonous, 50 mg constituting an approximate fatal dose. Exposure to white phosphorus should not exceed 0.1 mg/ms (8-hour time-weighted average - 40-hour work week). White phosphorus should be kept under water, as it is dangerously reactive in air, and it should be handled with forceps, as contact with the skin may cause severe burns. 

Fluorine in the atmosphere can be detected by chemical methods involving the displacement of halogens from haUdes. Dilute fluorine leaks are easily detected by passing a damp piece of starch iodide paper around the suspected area. The paper should be held with metal tongs or forceps to avoid contact with the gas stream and immediately darkens when fluorine is present. 

NaBH4 has also been crystd from isopropylamine by dissolving it in the solvent at reflux, cooling, filtering and allowing the solution to stand in a filter flask connected to a Dry-ice/acetone trap. After most of the solvent was passed over into the cold trap, crystals were removed with forceps, washed with dry diethyl ether and dried under vacuum. [Kim and Itoh J Phys Chem 91 126 1987.] Somewhat less pure crystals were obtained more rapidly by using Soxhlet extraction with only a small amount of solvent and extracting for about 8h. The... 

Use forceps or a brush and pan with broken glass never use the fingers, even with gloves. Disinfect broken glass arising from biological spills... 

Pinzette,/. forceps, tweezers, nippers, pincers. Pionier, m. pioneer (Mil.) engineer, -spreng-mittel, n, engineer explosive. 

Zange, /. (pair of) tongs pincers, nippers, forceps, pliers, tweezers. 

Lithium wire purchased from the Lithium Corporation of America, Inc. was used. The wire was cut in 2.5-5.0-cm. pieces, washed free of the protective oil with ether, and weighed by transferring quickly to a tared beaker containing mineral oil. The lengths of wire were again washed in a beaker of ether and then held with forceps over an open neck of the reaction flask (positive nitrogen flow), cut with scissors into 3-4-mm. pieces, and allowed to fall directly into the flask. 

Figure 4. Plutonium oxide (2.77 micrograms) weighed on September 10, 1942. It is shown on a platinum weighing boat magnified approximately 40-fold. The Pu oxide appears as a crusty deposit (indicated by the arrow) near the end of the platinum weighing boat, which is held with forceps that grip a small handle.

Forceps will be found useful in many circumstances. These are usually made of steel and should be designed so that there is no tendency for the soft ss to slip out easily. This will be avoided if the points are bent inwards so that they meet at an angle of about 25°. The forceps should either be long enough not to get too hot in use (about 10 inches long) or else they should be insulated in some way. 

If the gap between the two pieces is too large for the above method to be attempted it may be possible to fit a sleeve of wider tubing over the two tubes and fuse its ends down on to them. This method inevitably leads to a very thick-walled joint, but the excess glass can be pulled off with forceps or by fusing a glass rod on to the thick part and pulling it out. 

Devitrified glass should be pulled out of a joint with forceps or a glass rod, and if this leaves a thin-walled joint extra glass can be built on using thin rod. 

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