BOOK REVIEWS handle to insulate against heat. To prevent the hot glass from sticking to the reamer, it should be moved across a piece of beeswax while warm. I t is not overly clear how the mathematics involved in the latter part of the book are helpful in glass blowing. FRANK L. HAYES
Manual of Laboratory Glass-Blowing. R. H . Wright. 90 pages. Chemical Publishing Co., Brooklyn, N. Y. Price, $2.50. This manual of glass blowing is excellently presented, with photographic illustrations, and is worthy of study and use by those interested in this subject. The following suggestions are offered: (page 18, paragraph 2). The torch should be so THE TORCH mounted that it can be readily pulled out away from the bench. It is highly desirable that the glass blower sit or stand sideways to the bench, which should be a t his right. This allows greater freedom of movement and should be “an absolute must”, especia!ly in the fabrication of apparatus to be used in research laboratories. Where natural gas must be used a very serious problem is presented, in that this gas blows out very easily, even when oxygen is used. This trouble can be eliminated by tapping a hole in the gas feed of the torch and screwing in a short section of copper tubing 0.25 inch in diameter, to the other end of which has been attached a tiny Bunsen burner. This is then bent into place juht under the jet of the torch. A tiny flame is sufficient to keep the torch from blowing out, regardless of how fast a flow of oxy en is used. A valve is necessary in the Bunsen burner t o controfthe size of the flame. THE BLOWING TUBE(page 20, paragraph 1). The blowing tube is a very useful and necessary gadget, in its place. It is necessary to use it when the apparatus being worked on is too long, cumbersome, or stationary for the glass blower to bring it to his mouth to blow. All other types should be handled without it. Beginners especially should avoid its use on smaller articles, because a blow tube here hampers rather than helps the proper manipulation of the work. CUTTING FILES (page 20, paragraph 2). A ood file for cutting Pyrex is the &inch mill file, second cut. T h i s b e has four cutting edges, which can be ground and sharpened on an emery wheel over and over a ain. J O I N I N G ~ JOFBEQCAL E S SIZE(page 23, Chapter IV). When the ends of two pieces to be joined have been properly heated and pressed together (page 24, paragraph 2) they should be immediately pulled apart somewhat, so that the glass squashed together mill not be too thick. This is very helpful, whether the job is finished by spotting it together-that is, heating one spot a t a t i m e - o r whether it is rotated in the flame and heated all around the tube and then blown in and out several times. In this operation the beginner should avoid use of the blow tube. It is better to learn without it. Wherever the blow tube must be used, it should be attached to the tube or part held in the left hand. The heaviest, longest, or bulkiest part of any apparatus being worked on in the torch should be held in the left hand. The left hand should be held above the work. Figure 1, Plate 2, is a good example. Here the right hand is wrong. The right hand should be under the work and the tube held and rotated round and round or back and forth, between the thumb and first two or three fingers in unison with the left hand. It takes practice to master this procedure, but better results make the effort worth while. (Page 32, paragraph 1, last sentence.) In this operation the glass should never be “cut” with a file or knife. These tools leave a “white” mark on the edge of the glass which IS still there after the two tubes have been joined together. I t is especially important to eliminate these marks in vacuum apparatus, where they can easily cause trouble. For instance, if a leak is suspected somewhere in the ap aratus and an effort is made to find it with a high-frequency coil ?see page 75), another leak might be caused by the attraction that this white mark has for the spark from the coil. To avoid this the end of the tube-in fact, all pieces of glass that are to be joined or sealed together-should be blown open in the fire, never cut with file or knife. FLARIKG THE END OF A TUBE(page 55, bottom). In this operation a reamer made of brass is best to use. The thickness is not important; 1/18 inch is good. I n shape it is like half an elongated diamond, roughly 3 or 4 inches long, and about 1.5 or 2 inches a t its wide part. From the middle of its wide part an end projects for 2 inches or so, to which is attached a wooden
Chemical Analyses of the Waters of Oklahoma “Chemical Analyses of the Waters of Oklahoma” is the title of a 474-page book written by 0. M.Smith. and published as Bulletin 52 of the Engineering Experiment Station, Oklahoma Agricultural and Mechanical College, Stillwater, Okla. Considerably more than half of the volume consists of tables of analyses of city supplies, wells, lakes, ponds, and streams. This is a compilation that represents the joint effort of workers a t the Oklahoma Agricultural and Mechanical College, the Oklahoma State Health Department, and the Oklahoma Geological Survey, over several years. Robert H. Dott, director of the Oklahoma Geological Survey, and E. C. Warkentin, assistant state sanitary engineer of the Oklahoma State Health Department, are contributors.
Priorities on Laboratory Materials Priority assistance for materials required by scientific and technological laboratories and deliveries of laboratory equipment are affected by two amended orders (P-43 and L-144) issued June 26 by the War Production Board. Preference Rating Order P-43 as amended assigns preference ratings and an allotment symbol to assist laboratories in obtaining materials and equipment needed to carry on scientific or technological activities. All laboratories receive a preference rating and allotment symbol under the amended order; laboratories carrying on work of great importance to the war effort are entitled to obtain a serial number and may use a higher preference rating than other laboratories. All laboratories owned or operated by the Army or Navy receive high preference ratings. L-144 as amended restricts the delivery of any one item or quantity of the same item of laboratory equipment having a value of $50 or more, or delivery on a purchase order of laboratory equipment worth $200 or more, even though no item or quantity of the same item on the order has a value of $50 or more, unless authorized by the War Production Board on Form WPB-1414 (formerly PD-620). The order defines “laboratory equipment” to mean any apparatus, instrument, or the like, designed primarily for use in laboratories. Purchase orders of the Army and Navy, and laboratories which have obtained serial numbers under Preference Rating Order P-43 as amended, are exempted from this restriction, except on purchase orders for certain highly critical equipment named on List A attached to the order. Interpretation I to L-144, issued July 17, states that the same regulations governing delivery to domestic sources apply to deliveries for shipment t o foreign firms or individuals.
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