REVIEW OF PAPERS ON ANALYTICAL CHEMISTRY (INORGANIC) WHICH HAVE APPEARED DURING THE YEAR 1882. 131
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A iilot1itic;atioii of t h e ap11~r:it I I S f o r t i i t , n1)soliitct I ) I : T E R A I I S A T I O X iriventetl 1))- s, \v. J O ~ I I W I:iri(1 I E. 11. Jeiikiiis, is described by 7: .\', ( J t / ~ ~ ~ / i(.l /I ,I y~ I . ( 'ht / / 1 . J,,//r..I\-,. 4.2). According t o . I . G / i ; p ! v ( / ( ( ' / / e , / ( . Ll'rw~,,,XI,\-, l j ! i , A L L ACIDS ASD O S I I ) E S O F S I T R O ( ~ I : S : I I Y c.oiivcrtw1 into : t i i i i i i o i i i : i b y c.ombusi Tlie riiistrii,c. i h rn:icle i n the tion with iiiarsh gaq n i i d ~ 1 : Iiriie. proportioil of 7 5 grs. of sodiiiiti ;ic*ctatcwith 1; ox. (if soda linitt, and t l i t ' conibiistioii coiicluctcd iii t h e ordinary niaiinei.. ' h e tubc is charge(\ first with about oiic-quarter of the above mixture, then the remainder mixed with 5 t o grnis. of the srtbstnrice t o he examined is added, ant1 finally piirc s o h liinc. Tlie acriiracy of tlie results thiis obtained is disputed by J Ruffle, ( xi,?(*,q, 181;). I n esperinietitirig on methods for the I)ETERJIISATIOS OF xrrRocs O X I I ~ E ,lt: IIetiipel ( B e / . . I). (-'hew. UP.,.., SV., 903 et seep.) finds it extremely clifficrilt t o obtain absolutely pure S , O . The purest gas obtained contained 98.8%. H e finds the Lest method of estimating the gas to be by explosion with hydi*ogen in an apparatus specially designed for the purpose, which is caref rilly tlescrihed. 100 vols. N,O with 460 vols. 13 was not explosive, while 100 N,O with 116 vols. I3 caused siicli a violent explosion as to shatter the apparatiis. Tlie mixture therefore riiii3t be made within these limiis. Alkaline solutions of potassium permanganates or of chromic acid are recommended by C. B o e h e r :Pres. &its. AYLal. Chein., XXI., 212,:, as AIESORBESTS FOR S , O , in analytical processes. T o determine the amoiints of wilimn S U L P H I D E , SCLPHI'I'E A N D THIOSULPIIATE:in the same solution, G', E. D(ivis ( J O / ~ T . Cheni. Ik?., I., SO), deterniines, 1. The miourit of ioditle absorbecl by n measurcd quantity of tlie solution, b y coiiverting the :tlkslies preserit into bicarbonates with carbonic: acid water and titrating with iodine solution. 2. The aiiiouiit of sulphide aiid thiosulphate present ; by adding SrCI, in excess, digesting for about half a n hour a t G5" to 5O0 C . , filtering off the strontium su11~hite,washing with air free froin witer, adding carbonic acid water to the filtrate, and titrating with iodine solutioii. 3 . T h e airiou~itof thiosulphate. OF x I r R o ( ; E s ,
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p x n t ; by ,separating the sulphite as in 2, and then separating the sulphide by digestion for half an hour with CdCO,, filtering and titrating the filtrate with the same precautions as before. A correction must be applied to the results before calculating from the data obtained. It has been found that 100 cc. of a solution of SrSO, saturated at 65 to 79" C., consumes 0.3 cc. decinormal iodine, and the same bulk saturated at 12.7" C. consumes 0.16 cc. decinormal iodine solution. The bulk and temperature of the filtrates must therefore be taken. T o obtain the SULPHUR IN PYRITES in a form for estimation as sulphate, F3.. Bockmania (Fres. &its. Anal. C'hem, XXI. go), fuses 0.5 gms. with 26 gms. of a mixture containing 6 parts N a 2 C 0 , to 1 part KCIO,. In estimating C H L O R I N ~GRAVIMETRICALLY, D.Lindo ( Chem.News, XIV., 193) filters the A g C1 through a Gooch filter and dries for half an hour at 140 to 150" C. In the indirect estimation of CIILORINE AND BROYINE, L.P.Kinnicutt (Am. Chem. Jour., IV.,22), after weighing the mixed silver salts in a platinum crucible, reduces to metallic silver by a battery, the crucible being made the positive electrode of the circuit. The sanitary EXAMINATION OF GASES ESCAPISC: FROM CHEMICAL WORKS forms the subject of a paper by TV: J. Lovett (Jour. SOC. Chem. liad., I., 210). For nitrotis compounds the gases are brought into contact (by agitation) with hydrogen peroxide and water, the solution neutralized with pure soda solution (free from nitrates) evaporated to very small bulk, and after removing carbonic acid by a drop of sulphuric acid, using a Davis nitrometer tube with conc. H, SO, and mercury, the volume of N, 0 , being measured, For subhurozts acid the gases may be passed through a standard solution of potassium permanganate. For ozygen, the gas is caught in a U tube, one limb of which is sealed and graduated so as to form an eudiometer, and oxygen is absorbed by potassic hydrate and pyrogallic acid. For subhureded hydrogen the gas may be passed through Pb (NO,),, and the precipitate converted into sulphate and weighed, or the .excess of lead remaining in the solution titrated with potassium dichromate. For chlorine the gases are passed through KI solution, and the iodine set free titrated with sodium thiosulphate. To distinguish between the amounts of free and comhined chlorine in such escapes, G. 3.Bavis (loc. cit. p. 214) passes the gases through H2S water. The solution thus obtained is halved. One half is neutralized with Mg C O , , and then titrated with A g NO,,
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giving total chlorine ; the other half evaporated to neutrality without any addition and titrated, giving combined chlorine. T o determine the amount of OZONE IS THE AIR, B. Tomnzusi ( L e s Mondes, I [3] 123), draws a measured quantity through a tube having two branches The air passing through one branch is drawti directly through a standard solution of sodium arsenite ; that passing through the other branch is first passed over red-hot platinum sponge before passing into a solutioii of sodiuni arbenite The solutions are then titrated with potassium permanganate, and the, difference of the results in the two solutions serves as a basis for the calculation of the ozone present, as in the second solution the o/;one has been destroyed by the ignited platinum spongc Experiments on potassium permanganate in relation to its application for the EXAMINATIOS O F POTABLE wAi>ms,have been made by Ai.U u p e ( A n a l y s t VI1 1 JVater acidified with sulphuric. acid when absolutely pure, doe5 not decompose permanganate it1 R closed flask at SO0 F In ztandardizing the permanganate f o i Tidy’n test the operation should be performed 111 n closed flask. W i t h water? for domestic us? which arc. cornparati\ el. free froiii organic matter, the degree of temperature and thc. length of tinic for the action of the permanganate a$ well as the ysntity of pcr manganate, make but little difference 111 the results obtained. W i t h less pure waters the differences betwerii the 3 hoiir and 4 hour test were very decided. On using phosphoric ~ c i dinstead of iulpliuric in Tidy’s test, result5 much lower were obtained Thr acidition o f sulphuric acid and boiling before adding permanganate, increases the amounth of oxygen absorbed. Thib increase was very marked when the test was tried 011 pure water. t o which cane hugar, btarclt, or urine had been added, 1 J U t was much le64 marked when gelatine C 7 8 MudL C’ltcni .T070* 11or egg albumen was used 188) finds that in many waters examined, the distillate obtained b! distilling with sodium carbonate, affords more ammonia (determined by the Nessler) on redistilling with alkaline potassium ~ ~ ~ r n i a i i g a n a t c than if tlie Nessler test is directly applied to it. The O R ( ~ A N ISITROGEN ~ 111 waters, beel, etc , is estimatea by Ti: Bettel (Chem N L i u $ , XLV. 38), in one operation by distilling from a copper flask in R current of hydrogen with pure soda (from \odium) The use of‘ the copper flask admits of distillation to complete dryness, and ignition of the residnr At thc close of tlie operation to break up cyanides, &c., which may h a l e formed, n little potas-inm permanganate i q added, and heat again applied Nitrates, i f
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present, are previously converted into ammonia by the action of the zinc-copper couple. The distillate contains all the nitrogen in the form of ammonia. T o convert NITRATES AND NITRITES IN WATER into ammonia, El P.Perkins (Analyst VII. 66,) proposes the use of metallic magnesium aided perhaps by the addition of some Na C1. J; B. Kinnear (Chem. News, XLVI. 33 ) finds that zinc with a dilute acid will effect the reduction in about ten minutes, provided that there are about 5,000 parts of liquid present for every part of nitric nitrogen. The rapidity of the reduction depends somewhat upon the amount of surface of zinc exposed. Among delicate TESTS FOR NITRITES in water, A . Jorissen ( B e s . Zeits Anal. Chem. XXI. 210) proposes a solution containing 0.01 gm. fuchsin in 1OOcc. of glacial acetic acid, which gives a change of color, passing through blue and green to reddish yellow. (Noted by Vogel Joicr. Prakt. Chem. XCIV. 457), while E. TK B a v y ( Chenz News XLVI. 1) recommends for the same purpose acidifying the eolution, adding a f e w cc. of gallic acid and boiling. The presence of nitrites at once gives a tint to the water similar to that of the Nessler test with ammonia, The reaction is stated to be : C, H,O, $; 2 H N O,=C, H, O,+C 0,+2 N O + 2 H, 0 tanno-melanic acid being formed, The COLOR METER FOR WATEES used by Messrs. Crookes, Odling, and Tidy in their examination of the London water (Report to Local Government Board for 1881) is described (Chem. News XLV. 170). The two-foot tube is used. For comparison colors, two wedges, one brown, the other blue, are used, which are d i d over one anothen'until a tint corresponding to that in the water is obtained. The solutions contain respectively : Brown, 0.7 gm. metallic iron as ferric chloride 0.3 " '' cobalt ae chloride, and a slight excess of free acid per litre. Blue, 5 gms. pure crystallized cupric acid sulphate per litre. The results are recorded in figures representing the thickness in millimetres of the solutions required to simulate the color of the water thus : Brown : Blue, 20 : 10. Regarding the examination of fertilizers for REVERTED OR RETROGRADE PHOSPHATES, C, Richardson (Am. Chern. Jour. IV. 183) finds that the use of ammonium oxalate for their extraction gives variable results depending upon the time and temperature of diges-
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tion, the degree of concentration of tlie solution, &c. In this connection see also results of ?", ,$. Gk~cZdiy/(this AoimiaZ, p 113). i ? ,[ &y(l (J#io*. h 7 i 1 7 , (%I / / I ,&x'. S L I . 306) triturates 0.5 gni. of the fertilizer wit11
