... THE ANALYST 111Hupkin and Williams Ltd.have been noted, for many ‘years,for theirrangeofOrpic ‘,Reagen~ for the detection ordetermination of metals, andthe Company is publishing, La series of MOW (’,p p h r dating to these rc-agents.0The fillowing illonogrophr are walloblejre on reqms:-NO. 29 GTHORIN’-Reagent fur Thorium.NO. 30 GDITHIZONE’-Reagent for LeadNO. 31 <22’-DIQUINOLYL’-Reagent for Coppcr.NO. 32NO. 33cDITHIZONE’-Reagent for Mercury, Zinc, Cadmium and 8ismuth.‘NITROSO-R-SALT’-Reag~”t for Cobalt and Iron.I’I.C\IOU~ Monographs in the series have already been issued in collective form, under thctitle “Organic Reagents for Metals, and Other Reagent Monographs”, Volume I . Copies ofthis publication are still available at I q/- nett, post free.and full details will be sent on request.HOPKIN & WILLIAMS LimitedC H A D W E L L H E A T H . E S S E X . E N G L A N DBranches in LONDON ’ MANCHESTER ’ GLASCOW Agenb throughout the U.K. and all o w the Worldiv THE ANALYSTEl!iAlii .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ..........Now available: Vitamin FreeCasein HydrolysateThe above is added to our range,which includes :m Bacteriological Peptone m -tone m Acid Hydrolysed Casein m Bacteriological Gelatin m Corn Meal Extract m soya Peptone m Potato ExtractBacteriological Yeast ExtractDetails on request tram Division of OX0 Ltd.Thames House, London, EMCentral 9781.................... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .................... .........THE ANALYSTB.T.L. Sintered Glasswarefor filtrationB.T.L. Sintered Glassware is resistant to all reagents excepthydrofluoric acid and strong alkalis. Grades from pore Sizes 00 to 4give a complete range from rough filtration of coarse precipitatesto the “bright” filtration of the finest precipitates such as barium sulphate.Grade 5 filters, specially made and conforming to B.S. 1752-1952,are increasingly replacing ceramic filters for bacteriological work.B.T.L.Sintered Glass Filters are being used by Glaxo Laharatories Ltd.,in the manufacture of poliomyelitis vaccine and influenza virus vaccine.A full list of the range will be sent on request.V complete laboratory serviceW e are exhibiting at ACHEMA 58-STAND D3. HALL 6BAIRD 81 TATLOCK (LONDON) LTD., CHADWELL HEATH, ESSEX, ENGLANDBranches in London. Manehesrer ond Glassow. Ageirls throughour U.K. and 011 over !he world.T*s;BT.zvi THE ANALYSTL a b o r a t o ry apparatusJMC platinum apparatus and electrodes for chemicaland electrochemical analysis are available as standardor special designs for every application. Behindtheir production lie both sound theoreticalconsiderations and wide practical experience of theemployment of platinum apparatus and of users’requirements.Johnson MattheyJOHNSON, MATTHEY & CO..LIMITED, HATTON GARDEN, LONDON, E.C.lTelephone: Holborn 6989. Vimria Street. Birminghom. 1. Telephone: Centml 800.175-79 Eyre Street. Shcffield, I . Telephone: 2921THE ANALYST viiBariumCacsiumCalciumCopperIronLithiumMagnesiumMa"ga"eSePotassiumStrontiumAn important advancein flame photometry553.6 10.0852. I 2.0422.7 0.2324.8 I .o385.9 2.0670.8 0.02285.2 I .o403.3 0.2768.0 0. I460.7 0. I -UNICAMSP. 900SPECTROPHOTOMETERPOWERFULCorrect optical design provides accurate wavelength selectionover the range 250-1020 m p The high light-gathering power ofthe silica prism monochromator coupled with sensitive detectorsand a powerid amplitier give the SP.900 great poleniialiiies asa research tool and exlmml the ran@ of ilq applixtionc nn theroutine laboralow.The table shows the limits ofdetectability of various elementsin normal operating conditions.These results were obtained fromroutine production tests and donot necessarily indicate the ulti-mate performance of which theSP.900 iscapable. The results offurther tests will be published asthey become available.Theservices ofthe Unicam Appli-cations Laboratory are freelyavailable to investigate the suit-ability of the SP.900 to anyanalytical problem.A fully descriptive leaflet willgladly be sent on request.Local demonstrations are nowbeingarrangcd.Pleaselet usknowif you would like to have details.UNICAM INSTRUMENTSFAST.A sensitive direct reading galvanometer, operation on smallsample volumes, rapid setting-up p r o c e d u r d l are importanttime-saving features. The Flame Spectrophotometer is easilyconverted to a recording instrument with automatic wave-length scan.CONVENIENTCompact layout, logical disposition of controls, simple andquick-to-clean sampling system-these are some of the featuresthat distinguish the SP. 900 as a simple, convenient all-mainsinstrument, well-suited to the unskilled operatorviii THE ANALYSTThe potentialities of“Quickfit” Spherical GroundGlass JointsSpherical joints give you flexibility.They can always be separated readily.In conjunction with conical jointsthey discount rigidity incertain assemblies.Being groundto a peak standard of perfection they canbe used under the same conditionsto give the same high efficiencyof result as “Quickfit” Conical Joints.All particulars on request... - -Ib00 - ..05. nk a5TELEP Stone481H0NTHE ANALYST ixScveral hundred isoropically labelled compounds are now produced iegularly athmcrsham. They include an unrivalled range of materials needed for tracer worktn biology. pharmacology. medical diagnosis and therapy, and in many technicalapplicarinnsofchcmicalproducts-pesticides,u.eedkillers, hormoncr.andthc1ike.Most of there substances can be supplied from stock-or in rhc case ofshorr-lived sotoper, at rcasonablc notice--and their spccific activity and chemicilpurity are generally the highest available today.Somc exampler from our current production are:Compounds of Thmpentone-Sji, sodium saltPharmacologicalInterest: Cyrteamine-S j 1Sulphanilamidr, and other sulphonamides-Sj I6~Mercaptopurine~S jPhenoth;&e-SjDi-iiopropyl Ruorophosphonate-Pj 2TcrraiodnohenolDhthalcinI I 2 I4-lodoantfpyrine:In 5 1lodinarrd oils and fats-h j Ihlcrsalyl-HgmjSodium rtibogluconarc-Sbi ':1,,Agents: Sodium di-iroamyl rulphoruccinate-Sj $Sodium lavioylmcrhyltauridc-SjSodium lauryl sulphaie-SjiSurface-active Potassium ethvl xanthare-SIX THE ANALYST 4 ExternaladjustmentsLMicrobalance sensitivity and poise adjustments are mademuch easier by means of the new aluminium wing-nuts,operated ~xrerna/(v.This means that micro-balances can be keptat optimum performance quickly and simply.A detail, perhapsbut it is the sum of details like thisthat makes Oertling the choice of so many chemists.Plus, of course, the unique, nation-wide “after-sales” service forinspection, maintenance and repair by works-trained craftsmen.Write for full information to: L. Oertling, Ltd., St. Mary Cray,Kent, or ring Orpington 25771.b e t t e r weighing THE ANALYST xiPye for Chemical Instruments mPye scientific instruments are craftsman built,designed to meet the needs of research and industry;they are made to exacting standards giving utmostprecision and reliability.Our range of instrumentation covers electronicinstruments, electrical test gear, potentiometers,measuring microscopes, resistance bridges, chemicalinstruments-pH meters, conductivity meters-in fact,240 Merent items are listed in our main catalogue.Why not write for OUT latest edition: we shall be verypleased to assist you in your requirements andinstrument problems.GAS LIQUID CHROMATOGRAPHYEQUIPMENTCmdogue Number I1880A completely new instrument has been developedwhich is capable of high resolution and extremesensitivity.By means of the low noise Pye d.camplifier, connected between the katharometer bridgeand the recorder, the overall sensitivity of the systemis improved by as much as forty times. nUnder favourable conditions one microgram of a component in one millilitre ofcarrier gas gives full scale deflection.Switches are provided to change the sensitivity during a run by factors of 2,5 and 10over a wide range to a maximum sensitivity of 12.5 microvolts full scale on thepotentiometric recorder.Good temperature and pressure control ensures stability atsuch high sensitivity.In the range 50-250°C the katharometer temperature is controlled to within 0.05”C andthe column within 0.5”C. By a simple switching arrangement the temperature of eitherthe column or the katharometer may be indicated on the recorder in two ranges 50-150°Cor 150-250°C.AUTOMATIC TITRATIONEQUIPMENTThe Pye Automatic Titrator has beendesigned to combine wirh a variety of pH,millivolt and conductivity measuring insuu-ments for quick and accurate routinetitrations. This equipment will operate awide range of reagent adding devices andgive accurate control of dosing. Titrationreproducibility 1 drop.The illustration shows the AutomaticTitrator being used in conjunction wirhthe latest Pye pH meter/miUivoltmeter-the “Master”.W. G. PYE & CO., LTD.,GRANTA WORKS, NEWMARKET ROAD, CAMBRIDGE.Telephone: Combridge 54411. Telumrns: We. Cornbridlexii THE ANALYSTthe outstanding purities ofPOTASSIUM NITRATE A.R.KNOT no1 w, 101 I 1~ ~ ~~~ACTUAL BATCH ANALYSIS(Not merely maximum impurity valuer)Batch No 75401n!OChlmdc (CO Ow050.envy Metals (Pb) Ow02""dale (10,) No reactionIron (Fe) OM)O06°.Nitrite (NO,) No reacmnReaction (10"" solumn) p H 7 0Phosphate (PO.) O w o 4 , "This is the analysis of aJudactan reagent. And, as withevery other reagent in the seriesit is the actual batch analysis-it is one of several of whichwe are especially proud.1t