KEEPING UP
WITH ,CHEMISTRY
Acid costs (handling and storage). C. H. S. T ~ E O L M E . the iodine in five grams of biological material is d w i b e d with C h . Induslrhr. 42, 3%t401 (Apr, .1938).-"1" any chemical drawings of rhc apparatus. A n rlectromctric titration method is so refined that it seems to process, t h cost ~ of a con~unmbletool, su~,has hydrochloric and to iustifr sulfuric essential ~ ~acids~ in marrv ~ ~ oroccsscs. ~ - is suficient ~ exhaustive i~vestina&ns into its handlina and storage. 'since the price of the s&alled 'mineral acids' &counts for only forty t o fifty per cent. of the ultimate cost of employing it, the balance is necessarily an indication of the cost of conveying, storing and distributing it about the plant.". . . . "Rubber compositions of various kinds have been known and used long enough successfully t o indicate rubber as the substance promising the solution' of the problem. The early develooment was a eomoosition to which sufficient rieiditv or haidness was impartid t o permit of the construction df the vessel itself. Such was hard rubber, which has many useful applications. I t lacks, however, adaptability in apolication t o manv oarts of olant reauirine oratection since I t cannot be applied without' removing the vessel, and cannot he vulcanized save in a vulcanizer, the size of which limits the magnitude of the vessel to which it is applied. Moreover, it loses rigidity and is deformed a t comparatively low temurratures. and its brittleness renders i t orone t o fracture under variable temperatures. "Unappreciated qualities of soft elastic rubber compositions became recognized with the development of motor tires withstandine. as manv do. the mechanical stresses and abrasive action Gcidental tb a life of ten thousand miles and more. No Irs$ important is the new r6lc found for a new elastic ruhher compolition called "acid-rubber," now lorgcly used in rhe protection of iron. steel. wood. concrete. indeed. anv material of which cont&&i of Laenitide i a v be consiructed, from the action of acid. "'This is a deGnite composition having chemical and physical characteristics of great inertness to the action of aoid; astonishing tcnsile strenuth. Itttlt. less indeed than that of the containers it Drotects, w h h .its elasticity is so meat as to entirely preclude fracture of thc protccrire lining undcr any expansion or vibration. Cnlike the 'rubber' of cornrucrce, it can be applbd to the existing irrwular wrfarr.; in its nlastir condition and vulcanized where it siands without the iniermedianr of a 'vulcanizer.' thus lending itself admirably to applicatioi of existing plant without rem&i. "Another feature of acid-rubber is its adaptability t o circumstances. I t may be made inert to a large range of acid and alkaline liquids, and t o a great range t o temperatures without deformation by appropriately adjusting its components. I t s elasticity is under control from a maximum of expansibility where it will return to its original length, after being stretched ten times its length, to the hardness and brittleness of glass. A t this end of its adaptability it becomes the ebonite, vulcanite, or hard rubber alluded to. "In its soft elastic condition, such is its imperviousness that a relativelv thin caatina is absolutely liquid-tight: it is, therefore, relatikly inexpensive and very &sfto apply. Some early failures in effecting adhesion have now been overcome, and acidrubber is chemically welded to steel, etc., so permanently as t o A. T. B. defy removal." A new method for determination of iodine in five cubic centimeters of blood or other biological material. J. F. M c C ~ e s o o s AND A. C. B K A ~ O NJ . B i d Chtm., 123, G99 -710 (May, 19.18). - -A rnicrocomhunion tube and distillation method for kolating
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be one thousand times as srnsitivr as rhe starch-iodide method. E. D. W. The influence of pimiento pigments on the color of the eg y o k J . B i d . C h m . , 122, 655-9 $ ~ e b . , of fowls. W. L. & o m . 1938).-The feeding of pimiento t o fowls results in reddish orange pigmentation of the egg yolk, adipose tissue, skin, shanks, and beak. The red pigment of the pimiento is capsanthin, a dihydroxy monoketone. The pericarp contains zeaxanthin, cryptoxanthin, and @-carotene. I n order for a fowl to d e ~ o s i ta carotenoid in the eea volk or fat, i t appears t o be nec&sary that a t least one ring%< the molecule contain one, and only one, hydroxyl group. E. D. W. Wool fabric sterilization. ANON. Chem. Industries, 41, 499 (Nov.. 1937).-Workers in the Deoartment of Amiculture are laid tb have'dkovered a process f& sterilization 2 wool fabrics without damaging the fiber. While i t has been tried as yet only under laboratory conditions, the method is believed to have practical commercial possibilities. Tests will be made in drycleanine and other industrial ~ l a n t s . A. T. B. Hy&carbons converted t d f u e l gas by new process. J. A. GUYER. C h m . & Mel. Eng., 45, 3267.(fune, 1938).-Fuel gas can now be tailor-made t o fit individuai plant or domestic heating reauirements. The hvdrocarbon water =as Dracess combines two fundamental reactions, thermal decom&dion of hydrocarbon g a w and vapors, and water an* reartio& hetween hydrorarbms and srram. T h e reaction; arc (arrird out in a murlrrn-type. nadiant-heat tube furnace. The wnttr is oreheated bv a svstem are led into the of heat exchanxers The hvdrocarbon steam pipe a t the point of entry to the futnace. After passing over a catalyst this mixture is converted into HWG gas. Using natural gas as the hydrocarbon the gas obtained varies from 393 to 624 B.T.u.. 5.5 to 7 per cent. COX;7.3 to 14.9 per cent. CO; 36.2 to 57.5 HZ;18.5 to 47.0 per cent. saturated hydrocarbon; 1.6 to 4 per cent. unsaturated hydrocarbon. A flow diagram of the plant is given. J. W. H. Adsorption, absorption, and condensation in recovery of solvents. C. A. BULKELEY.Chem. & Met. Eng., 45, 300-5 (June, 1938).-Three distinct.methods are in use for the recovery of solvents, adsorption, absorption, and condensation. They are quite similar in principle, although they differ considerably in equipment and methods of operation. Under the adsorption methods activated carbon is the material most used. I t can take up eight to twenty-five per cent. of its weight of vapors. I t is relatively high in first cost, but usually pays a handsome return on the investment. Absorbents are usually liquids or solutions of solids in liquids. The ease of continuous operation of this method is its chief advantage. In the methods based on condensation the vapor-laden mixture is cooled sufficiently to liquefy a portion by the lowe"ng of the vapor tension. Two methods are used for cooling (1) passage over extended surface-cooling coils and (2) passage through a chamber wherein a refrigerated liquid is atomized by spray nozzles under pressure. The latter is considered to have the most inherent advantages. I t is suitable for use in almost all cases where re-circulation in a closed system is possible, and gives a cleaner exit gas mixture than can be secured by other means. J. W. H.
asses
NOVEMBER, 1938 HISTORICAL AND BIOGRAPHICAL
Gilding of copper among the pre-Columhian Indians. P. BERGS@E. Nalurc, 141,829 (May 7,1938).-The pre-Columhian mrli.ns nf -. the .--P~meralrlas diqtrict - - - ~ - - of ~ ~Ecuador eilded their cnooer ~- obiects ~- in a manner not used elsewhere eith& in ancient or modern times. Chemical analysis shows that the copper itself is alloyed with varying amounts of gold. No mercury can be detected. "Gilding must have been done by dipping the copper into a melted gold-copper eutectic (gold with about twenty per cent. copper) the melting point of which is some 200°C. lower than that of copper; or possibly, the gold-copper alloy was applied t o the copper and kept a t red heat on charcoal hy means of I The allov will then~ fuse,and run over the coooer - hlnwnine -...r.r.. --~ ~ without the use of flux being necessary, the reducing flame s&ring a glowing surface free of oxide. Investigations have shown that copper has a tendency t o absorb the melted alloy in the same manner as melted tin permeates copper or a zinc rod absorbs mercurv. The coooer nucleus thus becomes a nold-cw~eralloy -~--~ ~, richest in gold a t the surface, the amount d g o l d d&easing gradually." These Indians did not practice gilding merely far decoration but to increase the hardness of the copper. "Of ~
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the thirty-five fish-hwks found, all were gilded, but not one single specimen of thirty-two sewing needles discovered. The gold which nenetrates the comer fish-hooks makes the metal much harder;and hardness is ihe first consideration in a fish-hook." M. E. W. Dr. A. E. Dunstan and petroleum technology. ANON. Nature. 141. 721 D AD^. 23. 1938).-The Redwood Medal of the 1nsiituti6n of ~eiroleum~echnologistshas been awarded t o Dr. A. E. Dunstan. He was born a t She5eld in 1878. He qtlldied a~~. t the Roval of Science. at --~ - - Colleee - ~~-~ ~ South . . Kensineton. ~ University College, London under Ramsay, and a t k as ti on don Collexe uuder Hewitt. At University College he collaborated with -Trouton in studying the correlation between physical properties and chemical constitution. From 1905 to 1915 he served as head of the chemistry department of East Ham Technical College, after which he joined the Anglo-Persian Oil Company. In 1916 Dunstan, Lomax, and Thole dealt with the Gyrogenesis of hydrocarbons and described the evolution of the cracking process and of the principles underlying it. M. E. W.
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EDUCATIONAL MEASUREMENTS AND DATA
H. B.
Criteria for evaluating course-of-study materials.
BRUNER. Teachers Coll. Record, 39, 107-20 (Nov., 1937).-In
1987 ... there were 30.000 seoarate subiect courses of study and 10,000 generaica"r&s whifh had been received by the CGriculum Laboratory of Teachers College. Criteria used by the Curriculum Laboratory in evaluating courses of study were as follows: 1. Philosonhv
2.
Content . . (a) Authenticity (b) Utility (c) Adequacy and significance (d) Organization
3. Activities (a) Pupil purposing (b) Interest and needs (6) Swial values ( d ) Reality (e) Variety
8 .
4.
i%Z%ting
F
activity
Evaluation of ~ 's . u ~ i lwork (a) Purposes (6) Variety (c) Validity (d) Areas of growth (e) Interpretation ~
Interpretive statements are included under each of the above criteria. Of 1750 science courses of study 20.2 per cent. or 353 were judged outstanding. This percentage is second highest, C. M. P. being exceeded only by the social studies. The measurement of teaching (appraising the teacher by the continued interest of his students). H. BEAUMONT. J . Higher Educ., 9. 96-8 (Feb., 1938).-In connection with promotional policies &I salary adjwtmentc, collvgr ndminictrators have clcreloped several tcchnics fur t hc purpose of e\timating the teaching ahihrv of a n instructor. cwrciallv in comvaricon with his roll & & in the drpartn&n ' SO& of thesc mcrhods has proved entirrly sstwfarrory. rirher because of insufficient ohj~ctivtryor hccause of too yrcat rinphasis on quantitattve aspects. The
former objection applies t o questionnaire and rating-scale methods: the latter, to those which evaluate the results of teaching introductory courses on the basis of the number of departmental majors produced. -The method suggested in this article attempts t o circumvent these abjections by proposing an objective measure of the individual instructor's success in teaching elementary courses, which is expressed in terms of the quality of his students who continue their work in the department, and of the type of work which they do in advanced courses. I n brief, the proposed technic consists of a follow-up study of students in introductorycourses. The simplest and most obvious measure of teaching results is obtained by computing the proportion of students in each section who take advanced work in the department after haviw passed the elementary course. A similnr;equally crude, measuie~isobtained by comparing each instructor's share of the enrolmeur in the introductory course to rhe orooortion of ndvanced students which has bren derived from hi s "bheiunina" sections. A m& refined indicator of teaching effectiveness is gained by determining, in each introductory section, the proportion of students obtaining each of the different marks who continue their work in the denartment. This nrovides a means of comparing individual indtructors with one another and to the departmental average in respect t o the extent to which they succeed in motivating students of superior promise to take advanced work in the department. The sunnested technic ~rovidesa composite picture of the effectiveneg of teaching &troductory c6urses 'm terms of the number and type of students prepared for advanced work and the quantity and quality of the advanced work done by them. If used with DroDer rec cautions and intemreted with discretion, this method me&& a t least one of the aspects of teaching success. Its prinripnl advantages arc that the data can be obtained with little d~ficulty,that it possesses a high degree of ohirrtivitv. and that it affords a direct means of ratinn and ronki n i the inhividual instructors in a department. 1t; chief disa&anmge~arc that it can be used onl; to evaluate introductory instruction, and that it fails to eliminate many of the extraneous facrors ~~~-~which haw made nrfviouslr ~roooscdmethod$ ineffective. It must be stated ;mohaticiliy, however, that its purpose is mcrely to dtsclo,c a factual siiuatirm and in no sense to attempt a causal exphnanon of indiwdunl differcnccs with respect to the rffectivt:ness of tenchln~mtroductury coursc~. A. T. M. The advantages of the "long form" of the periodic table. L. S. FOSTER. Rept. Nnu Eng. Assoc. Chem. Teachers, 39,2330 (Sept., 1937).-The conservatism of textbook writers causes a delay of many years after the promulgation of new theories before ~~~
they are presented to students. This conservatism acmnnts for the continued use of the older 'short form" rather t h m the various trwdifiracioncof ihe'long form" which war first suggesled hv Hanv in lh93 and imnruvrd hv Wrrncr in Id05 The numb& of modifications of th; periodictable that have been proposed seems to indicate that each teacher feels that it is compulsory for him to develop a new type. No table can be considered a complete representation of all the properties, but from the standpoint of teachinn and from the viewmint of the student, selection of the simplest and the least misrepresenting type would seem to he the best compromise. The table proposed by this author has the following advantages: (1) it shows plainly thenumber of elements in each period, (2) the non-metals are all located a t the far right just to the left of the inert gases, (3) the essential metallic character of the transitional elements is not masked, (4) the inert gases are a t the end of the periods instead of at the beginning, (5) in-
terpretation of the periodicity of the elements in terms of the current theory of ntw& srrucrtire is facilitated, and ti family rrlatiomhip, nrr nor obwured. Student in a q u d y of the penodic table s h ~ u l dbe fxmiliar with the follvwine f w r u r e s : ~ I ,I ueriodq. horizontal rows, (2) groups, vertical col&ns, (3) the elements that are strictly non-metallic, (4) the elements having both metallic and non-metallic forms. (5) the division of the elements into types such as inert gases, normal elements, transitional elements, rare earth elements. and (6) radioactive elements. From a discussion of the valences exhibited by the elements it becomes apparent that the relationships are quite complex and that the use of the longer expanded form of table correlates the data more adequately than the conventional type. Anyone who wishes to obtain printed cards showing the expanded form proposed by Professor Foster should send his request to William 0.Brooks, Technical High School, Springfield, Massachusetts. W. 0.B.
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THJ3 PHILOSOPHY OF EDUCATION
A study in the establishment of a norm in scientific attitudes and abilities among ninth-year pupils. G. C. WOOD. S d . Educ., 21, 140-6 (Oct., 1937).-The investigator attempted t o determine which Of the entering class of the James Monroe High School, New York City, practiced certain scientific attitudes or possessed certain abilities ordinarily associated with scientific attitudes. The attitudes tested for were: (1) honesty; (2) good habits of work; (3) initiative; (4) dependability; (5)
openmindedness; and (6) group courtesy and cooperation. Some 2600 observations were made on 210 boys and 76 girls in 1934 and 12.825 observations on 619 boys and 410 girls in 1935 Honesty ranked lowest of traits measured. Boys excelled ininitiative and girls in habits of work; both were equal in openmindedness. Repeated near the Of the school year indicated some gains had been made. C. M. P.
Industry, science and labor represcntstives explore silicosis prevention. C h ~ m .? J l r t . E n g . 44, 4RWl ( A w . 1997) Silicocis is a disms* of thc h n z r in whirh the normal lunn [issue is replaced by fibrous or scar tissue caused by b r e a t t h g air containing silica dust. The development of miliary nodulation in both lungs is necessary in order to make a definite diagnosis. Silicosis often induces tuberculosis and it isusually the tuherculosis which disables and kills the silicotie individual. The harm produced is primarily the result of chemical action in addition to possible mechanical effectsof silica on the lung tissue. The extent of damage done depends on the concentration of the silica in the air, the sizes of the silica +articles, the length of exposure, and to somr extent the other constituents of the atmos? pheric dust. Although the primary solution of the silicosis problem is prevention it is felt that those who have contracted the disease should he compensated just as those who are injured in accidents. J. W.H. Economics of some of the less familiar elements. H. C. M ~ u e n . Ind. E m . C h m . . 30. 4 3 1 4 (Aor.. 1938).-Althounh most of the less familiar e ~ e k e n i were s dis&v&ed o& a century ago, their industrial application is quite recent, due to inadequate methods of recovery, ideas that their tonnage was limited and the failure to combine academic studies with industrial needs. Analyses indicate that the lithosphere (the earth's crust to a depth of ten miles) contains about 71,900 tons of Ti, 3000 tons of Zr, 456 tons of Li, 114 tons of Be per cubic mile so that even Li present to the extent of 0.004 per cent. might someday he recovered. considerim that Br oresent to the extent of 0.0067 Der cent. in s& water (435 tons per cubic mile) is heing extracted. The commercial ares of Be, Li, Ti, and Zr, their location, and production are b r i d y discussed. For example, Zr is nineteenth in abundance. rankine ahead of Ni. Va. Cu. Zu. Ph. and B. Refined zircon sand is used to reduce coefficient of e x p h i o n in porcelain and ceramic bodies, and increase dielectric strength in spark plugs. I t is also used in the manufacture of molds for cast D. C. L. steel and insulators in electric heating devices. Nontoxic seleniferous soils. H. W. LAKIN. K. T. WILLIAMS. AND G. H. BYERS,Ind. Eng. C h m . , 30, 599-600 (May. 1938).The widespread occurrence of Se in soils has been extensively investigated and i r has been assumed that the presence of consid-
erable amounts of Se is tantamount to injury t o the normal function of the soil. I t is here shown that areas exist where high Se content in the soil does not produce toxic vegetation and the implied assumptions in previous work a~erunwarranted. Certain plants show selective adsorption of Se, while others show a limited tolerance. I n Hawaii, a high Se content in the soil showed that the venetation contained less than three Darts Der million Se. ~i1let;grown on soil containing 12 P . P M . contained no Sr. but when drown in I V a h s h soil contuining 2 r.I,.n. Sr a i sodium srlanete, it contained I.4tfil 1..ls..\1. Hawaii W 3 S t h firit ~ arc3 n.itll a hich Sc content whrrr the vrretatton was ron*istrntlv low in Se. AVmore extensive investigaaoh in Puerto Rico gave sinlil:u rciulti in the L'nitrd S t a t r i n d Cbnada soil rontainitlp as lttrlc 35 11.2 P P.M.pruduccld toutr scltntfrroui wgctation. 11 had orcviouslr bcen shown that when sodium sclenite solutions are shaken &th highly ferruginous soils, the Se is rendered insoluble. In both of these sections investigated, the iron content of the soil is high. D. C. L. On the fat of the land. ANON. Ind. Bul. of Arthur D. Little. Inc.. 137. 3 4 (Tune. 1938).-The United States Droduces an almost incr6dible amo;nt of 'animal and vegetable 'fats and oils, yet imported last year nearly three billion pounds to complete our requirements. We raised about seventy per cent. of our edible fat and oil requirements, importing principally coconut oil, palm oil, and olive oil. The paint and varnish industry imported largely linseed oil, tuug, and perilla oil to supplement a sizable home production of linseed and soy-bean oils as well as fish oil. The soap industry uses the greater part of the inedible made of non-drvinn fats and oils. For soap to be auick latherYng, it must contain appreciable amaunts of sodkm laurate. Coconut oil is high in lauric fat. To get around the tariff on coconut oil, the soap makers have found two substitutes of imoortance: d m kernel oil from Africa and the Indies. and babassu b i ~from ~ r a z i l . Water-soluble and water-miscible oils are of great value in the processing of leather. Castor oil may be comhined with sulfuric acid to make a water-soluble oily product. Enormous amounts of oils are being hydrogenated, fish oils for fine soap stock, cotton-seed oil for vegetable shortening, and in Germany petroleum as a raw material for soap. G.0. Promising platinum find on Colorado public land. ANON. Sci. Nevs Letter, 3 3 , 3 9 4 5 (June 18, 1 9 3 8 ) . T h e U.S. Geological
