ay ae ye GALT eae P s 3, rn bald . L ave ea ge la a ets} + hd a a ee ai i vada ¥ & @aar ay i. Fy THS Se2ECP OF MOISTURE CONVENT) URLPERAGURS, AND COLPACTION UPON TH iOVELAN? OF SOLUBLE SALTS Il SOILS. THssIs Submitted to the Faculty of the Michisan Agricultural Colleze in Partial Fulfillment of the Requirements for the Derree of Master of Science. Lawrence Clifford Wheeting. eee, October 1917. THESIS CONTSUTS. le Introduction. 2. Historical Resume 3. Experiments.- I. If. Til. Moisture Studies.- a. Hffects of different moisture contents on the movement of Salts thru soils. b. 2ffects of an already present salt (Caco, ) on the movements of other salts. ec. sffects of air spaces in soil, upon the movement of moisture from water treated to salt treated soils. ~—eee temperature studies. a. sffects of two temperatures upon the rate of salt and and moisture movement in soils. Compaction Studies. a. sffects of different degrees of Compaction unon rate of salt and moisture movements in soils. 4, Additional Remerks. 5. Summary and Conclusions. 6. Acknowlei:vements. 7. Bibliocvraphy. THa SrFACT OF MOISTUPS CONTENT, GVaNPePATURZ, AMD COM FAiccIoNn UPON TH MOVSLANT OF SOLUBLE SALDS IN SOrLs. Introduction. A review of the available literature concerning the movement of soluble salts in soils, brings forth, for the most part, only meagre and somewhat contradictory ideas, and it was, therefore, considered of sufficient importance to investigate some points with regard to salt movements, which might tend to clear up the doubts surrounding the subject. Certain definite statements are sometimes made concerning salt movements as,the tendency of nitrates to rise and of phosphatic salts to become fixed in soils. It is believed that the lateral movement of fertilizer salts in plot experiments is open to discussion. The questions as - do nitrates elways move upward, or sidewise and downi:nrd as well; are pnosphate salts movable; and do salts move equally in all directions,- ere important. It seems also hicnly desirahle to xnow what effect different Salts, varying moisture contents, chan-es of tempersture, and compaction have upon these movements. Indeed, there seems to be a largze field of research surrounding the addition of a salt to the soil and what ultimate- Ly becomes of it. Absorption, water movements, texture of the medium, chemical reections seem to be concerned and eas a result @ very complex cet of conditions srise. Hence, there is diff#4¢- culty in explaining many of the phenomena found. After showing (1) that salts actually move when added to a soil it Seemed advisable to investizate in this thesis the following pnases. (1) The effect of different moisture con- tents uoon the rate and distence of the salt movements. Le (2) The effect of temperature upon the rate and distance of move- ment. (3) The effect of different degrees of compaction upon the rate and distance of movement. s e 6 Historical Resume Liuntz, A. and Gaudechon, H. (2) using a field soil, which in an air dry condition contained 3.2% moisture, and placing St four points in a box about 0.5 em. of crystalline Nano, in @ place, found a moist area 10 t@.m. in diameter formed around the erystals which at the end of eifht days had reached 31-40 m.m in Ciameter. ‘The water content at the middle of the spot was found to be 7 S70 Upon setting up a zarden soil in a similar manner, analyses made for salt after two months showed no movement, but & movement of moisture wes found as before, With a similar soil containing 17.5% moisture no movement could be detected after three days with either KCl or NakO respectively. At 15.6% moist- ure, after six days, no selt was ietected 2-0 Mm. away from the deposit. . , Other experiments show only extremely slow or no movement either vertically or horizontally. Seeds placed in these boxes did not grow, due to the high salt content in the moist area and to lack of moisture surrounding the sslt spots. At hither moisture contents, the water movement toward the salt is not marked, and no selt move- ment occurSe The autnors believe that under field conditions salts will remain localized for lonz periods. ‘The same authors, two years later(3) reported results which substantiate their previous investizations. They maintain that when a salt is added to a Se homogeneous mass of soil, two systems result inasmuch as the salt solution hes a high vapor pressure. Conseauently a distillation of vapor results, which explains the collecting of the water around the salt deposit. ‘this concentration of tne soil solution around a salt deposit may be harmful to fermination. Demolon and Brouet (4) reported no difference other than a displacement of salt by movement of weter, as the result of rain- fall. ‘nese authors used FCl and hand, respectively in their work. valnreaux, L., and Defort, A., (5) investizated the move- ment of nitrates in boxes of soil, and under field conditions. In boxes @ very unequal distribution was found at 5 e.m., 10 c.m - 15 cer. from the orizinal devosit. Vertical diffusion did not appear more rapid tnan horizontal movement. In the field, eid, was buried at a depth of 25,50, 75 and 100 c.m., and after a suitable time sémcles were taken eight Cem. down and five cem.e out from the deposit. At eleven days portions of the 25 c.m. derosit had reached the surface, at 31 days Some of the 50 cem. deposit was detected, at 43 days the 75 c.m. derosit wes noticed, while at tnis time the 100 c.m. devosit Showed only a tracee In cultivated plots, rain hac wasned the nitrate down 20-50 c.m. and for every depth of denosit, tnere was @ zone of meximum nitrate concentration. On the wrole, the nitrate wes nesrer to the surface at tne end of the Season tran at the bovtinning. The same investivetors (6), the follvewing year, revorted furtrer results, snowins tnet if nitrates are csusnt in the evap- “= Oration current, wrey may be broursht un lons distances and eat a converatively ravid rate. “ven in vet seasons the nitrate will rise eno -7h to be within tve revcen of vlent roots. “hey snow 4. that after one month of wet weather, tne zone of maximum nitrete content is 20 - 40 c.m. decp, while a month of dry weather, causes them to collect near the surface. ‘the total amount of nitrate in tre 40 com. of soil resained netrly constant for the season. On crorped nlots tre upper lsyers viere removed by tre crops and hence the tendency in all cases was to »oroduce a uniform distribution. .he crop snowed beneficiél exfects of nitrate. ‘here man, then, reoort & Vivsorous Verticus ove isnt oT nitrates. Accordins to Frear, Vy. (7) there are two vroecesses which tend to lift dissolved meterials from the subsoil, namely, capvillarity snd diffusion. tins is cited by rear e&s snying that nitrites, chlorices and sulphnetes tend to accumulate in tre surface soil. Calcium and marsnesium rise more slowly. Potassium risss very Slowly, anc phosnnorus scarcely at ell. Pellet also cited by ¥rear in this bulletin says that the soluble salts of the soil are of two classes. 1. Those that tend to rise to the surface. 2. Those that tend to sink to the suosoil. liost salts tend to rise, but esvecially deliauescent ones such as E09 and Cal. Sink. lime in combina- 3 tion witn strons mineral acids will rise but Since it is usvally found as a Silicate or chloride its movement is very slixht. “rear further states that diffision is the tendency of soluble materiels to make & nomosanous solution. In soil, this adjustment is slow, due to tne discontinuity of tre film water or to colloids. Under systems of irritation many salts move ranidly but this is more of a translocstion then movement by diffusion. Sherp (8), in 1916, renorted effects broucht about by the adsition of sodium salts to a clay loam soil in cylinders and the Subsecuent washin= by waiter. re found a diffusion of soil colloids and a merzed retardation of tre rate of nercolation. Increased 5e amounts of calcium end masnesium in the percolate led him to believe that chemical processes and substitution Of beses were concerned in the chanres resulting from additions of the salts. He also believes that an actual movement of soil perticles occurs, but the greater factor in the diffusion explains on chemical grounds, Water movements N by surface tension or otherwise influence salt movement. axpnerimental Results The work reported in tre followins pezes is not completed in many resvects, and snould be conSidered rather as an investization to obtain ideas, which will open up new fields of thoucnt and re- Sexrch. Some divisions are more complete than others but it is be-~ lieved that enoush work has been done with each pnase, to either establish ea principle, or to provide a sound besis for further study. with tnese thines in mind, the examination of the experimen- tel results may be more intellizently accomplished. I. a. affects of Varying noisture Conditions upon the Lovements of Salts and Vater in Soils. Method.- tless cylinders, 8 inches long and 1 7/8 incnes in diameter were employed in this series. ‘he cylinders were filled about one-nalf full of soil which had been made up to the desired moisture contents then 2 trems of chemically pure crystalline potass- ium chloride and sodium carbonate reSpectively were put in and uni- formally spread over the survace. ‘ne tube was then filled with the soil end finally sealed at both ends with melted paraffin. In order to eliminate variations in comvection all tuoes received equal weichts of soil, and the compaction necessary to vlace this definite weisht into the cylinders, w&s practically the seme Be throughout the series. Precautions were taken to prevent undue losses of moisture by evaporation during the process of filling. The filled cylinders then had about four inches of soil on each side of the 2 am. deposit of salt; the soil weiszhins 500 grams in the case oz sand and 450 zsrams when silt loam was used, These cylinders were set away at a nearly constant temperature of 18°C for suitable lengths of time, in this series for periods of ten and twenty days. after which, they were opened, and one inch lay- ers of the soil removed, placed in weished aluminum cans and dried, at 103° for about forty-eight hours. They were then cooled and weighed, and the moisture calculated in percent, for each section. The salt movement itself wes detected by means of the freez- ing point apvsratus described by Bouyoucos (9). The reading ob- tained subtracted from the freezing point of distilled weter, gives the depression of the soil solution. When this depression exceeds the depression of e control. soil, that is, one which has no salt content, then it is an indication of a salt in the solution. For selts in solution cause a lowering of the freezing point, in provortion to the amount of salt present. Faint traces may be detected, since depressions of 0.002°C, can be read. ‘he Freezinz Point Lowerings expressed in the tables are obtained by the subtraction of tne standard or check depression, from that of each section. or instance the sand used, freezes with a depression of .015°C, with 25, water. ‘hen .015 is subtracted from all depressions of the sections frozen at the same moisture content and the true lowering, below tne check is thus obtained. The first series of moisture experiments were run witn air dry medium sand, and silt loam, over 10 and 20 day periods. whe results of the work are riven in ‘table | It will be noticed a @ Te that no movement or salt or moisture resulted. It appears, then that soils with only the so-called hysroscopiec moisture content are inactive with respect to salt and moisture movements. ‘his is probably due to unvailability of this form of soil moisture as well 2s to the lack of continuous contact in the column. Since diffusion of salt, as well as movement of water depends upon the continuity of the system it cen be readily understood why no movements have taxen pleceée The lioveme Inches from Salt Layer Si After 10 days Freezing| Moi Point Con Lowering Pr oO wb KF KY BH BN 1. le le l. 1. 1. Pon FF wD wA 1.4 1.4 1.4! none 1.5: 1.63 1.5: 1.6’ 1.7¢ with it loam ning but ods of re- move~= the sture layers. is in the ilt loam. of when detect- es at 20 the 10 inch ed in 10 Se ii tend ult of her unding t the oisture De The second series of experiments were carried on with medium sand at a moisture content of 0.5%, and with silt silt loam at 2.0% moisture. Some difficulty was encountered in obtaining a homozeneous mixture with such small quantities of water, but fairly uniform columns were obtained. The results for petiods of 10 and 20 days sare shown in table II. In contrast with the re- sults of Table I., these data, show both salt and moisture move- ments. The appearance of a dark ring around the zone where the salt was placed, was plainly due to the increase in the moisture content which collected there at the expense of the outward layers. The salts moved only as far as this dark zone proceeded, as is shown by the data in the table. This zone was most marked in the case of potassium chloride and sand, but showed well with silt loam. The sodium carbonate was less active under these conditions of moisture in case of sand and was inactive with silt loam. \hen potassium chloride was added to the silt loam, the salt was detect- ed one inch away after 10 days and had proceeded three inches at the end of 20 days. Bodium carbonate moved but one inch in 20 days and a lower concentration only is shown at the end of the 10 day period. In sand, the potassium chloride moved but one inch in £0 days altznourh the concentration of tnis layer increased throurhout the period. ‘he Sodium carbonate moved one inch in 10 days and showed traces two inches away at the end of £0 days. Hence, salts vary in their action in different media, but ali tend to set up two systems in the column. One system is the result of the movement of moisture toward the salt deposit and the other is brousht about by the movement of the sslt into the surrounding medium. This water movement, if ranid, must retard somewhat the movement of the salt. On the other hand, the increase ot moisture 10. in any zone, tencs to inc:ease the rate of salt translocation. It seems to be difficult to deterinine just wnat effect the moisture movements have upon the salt movements, in this case, at least. The Movements °: a and Inches | Silt . from ‘After 10 days A: Salt ‘Freezing |Moisturéd Layer . Point Content | lue Lowering | 4 0.300! 2.39 | 1 3 e900 62645, 2 e000 2052 1 e150 3046 1 ~ 840 3.86 , en 2 ©0000 2.55 e 3 e000 2260 | ‘e 4 ©000 £052 4, 0.000 2-68 1s 3 e000 £90 : | 1S 2 ~000 2475 ver 1 ~050 5.17 s0il 1 2070 2.78 I 2 ~000 2.68 Oric 3 e000 278 | ar= 4, e000 ' 2270 | | : . ms ) at >Om 12. In Table III, is ziven the data from the treatment of silt loam at 4,5 moisture, and medium sand at 1% moisture with Potassium chloride and sodium carbonate respectively. These deta snow very clearly in all céses the movement of wster towards the salt deoosits, and in comrsrin=s theSe movements with those in 2a0le II, it seems evident that the incressed moisture present accompanies greater salt and water moverents. ‘this is perhaps due to the sreater number of contsxcts, and the freater continuity of tre films ground tne particles of the colum. ‘Whe s2lt solution in the vicinity or tre denosit is doubtless a very concentr- ted One, end its surtuce tension is tnen mirve-ly incressed. ‘the Solution surrou.dinzg the soil in tne outer layers is less con- centraied, an’ therefore, has a much lover surfice tension. ‘hen if there is a continuous contact between these solutions the one with salt and the Srester surfece tension will witharew moisture from the otnrer. “his no doubt exnlains wry tre water collects 4. around tne selt devosits. at tre Same time the salt solutions are diztfusinz into tre soil moisture, trve to tre law concerning them, woich stéeves that all solutions tend to become homozeneous throwcrhout, if left in coiutact lon= enourh. Oxreriments run over lon norioés of time result in 2 uniform concentretion of the soil solution for all sections of tne column. the data or ‘Viable III show thet in silt loem at this ~oisture couteat, rovesscium crhlopice -~ e¢ pullin cover but in send, tne socium car- A | m4 5. mena ge a ey rege tre ~vrervtest water - 4 constie lests, ct lenst st tre 10 Csy nericd. v-he potsssium @vlorife s.:0WS “renver aevivity trrov~sout tre sccrries, end seems less influenced b77 tre tOvenent of the wa fe nes often moved out tree incves, viile ouiy tro First ines from the s.lt de-osit sows any ineresse in moisture content. 15. The socium cerbonate soers to be move locslized end remnins in tre zone of hi'n moisture content. It Sees cifvticvlt to deter- mine tre cause of these varisvions unless trey can be exvléined by relative solunilities on differences in tre mobility of ions. | | The Movenents q | Inecnes Silt ] from After 10 cays A alt Sreezing|loisture Layer voint Content Loverins 4 0.000 4,59 3 0005 4,08 2 030 | 5.56 1 1.260 | 7.12 2 020 | 3,51 3 .000 | 4,19 4, 000 ;, 4.31 4 0.000 4.91 3 «000 4.84 2 ©000 4.28 1 «160 6.58 1 e210 5.48 2 «000 4.09 3 ~000 4.57 4 e000 4.59 very in cone ro- the of ium out i of c 10 mtents 15. wnen potéssium cnloride wus olaced in contect with silt loam at 6; moisture end with medium sand at 2% moisture the waver pulling capacity of the sslt, wnich was very noticeable from tne results siven in Yteble III, seemed to be chanced. ‘The zone immediétely Surrounding the salt deposit did not hold very much more water than the other sections of the column, snd in sand the layers throusrnout were almost uniform in moisture con- tent. A very marked movement of sslt occurred, however, vro- bably because of the better cont-ct between all parts, and the fact that there was undoubtedly a fester rate of solution of the salt resultirs from more watcr beinse present. The sodium cerbonate still showed power to pull water in both soils, but its movement wes very limited, and confined to the zone of high moisture content as before. A consideration of the data ziven in Table V is interesting. It was found that no appreci- able variation in tre moisture contents of the different sec- tions could be detected for either salt in silt loam at 10% moisture. In sand with 5, moisture the potessium chloride gave analozous results, but tre sodium cserbonete still increased the water content in tne first inch. There was this change, hoveaver, the sodium czerbonate moved three inches in 20 ¢ays, which is a noteble incresise over othrer series run. ‘the potass- ium chloride wes aveain more active tnan it was under the con- ditions noted in Table LV, and has been detected at the end of the tubes after 20 days, and three inches out at the end of 10 days. Both salts «ve moved fert’er with these moisture contents tnan with the lower ones, preceding. The Movements 0: STit Loam Inches! from |After 10 days Aft Salt Freezing lioisturerrt Leyer Point Content. Po ‘Lowering | Loy 4 0.000 6.69 O.| 3 .015 «6.9L ti(a 2 e190 6.93 °| 1 2960 7.64 . 1 1.155 , 7.50 ° 2 330 6.89 °. 3 0015 6.51 : _4 | .010 . 6.36 _ . 4 0.000 6.19 0. 3 .000 6.20 ° 2 ~000 5.79 ° 1 ~105 8.30 °. 1 ~300 8.75 ‘ 2 ~000 5.77 ‘| 3 2000 6.16 ° 4 ~000 6.19 : | The Movements Inches: Silt Lo from After 10 days _A Salt ‘Freezing! lMoistur Layer Point Content Lowering | 4 0.000 8.72 3 020 8.81 L © 165 8.92 1 «480 8.64 1 620 8.71 2 216 8.80 3 ©0350 8.68 4 e000 8.73 4. 0.000 8.90 3 000 8.92 ra ~020 6.88 1 ~020 8.96 1 ~810 8.70 £ e018 8.84 3 ~000 8.78 4, e000 8.80 sure ind ‘et in 18. As a final series, the soils were made up to high moisture contents end run at 9% in sand, and 20% in silt loam. ‘The data are given in Table VI, and when compared witr Table V, show but little if any increase in the amount or distance that the salt has moved. It may be sately said then, that at 3% moisture in sand, and et 10, moisture in silt loan, the maximum activity has been reached, and further additions of moisture have but a slizht effect in hastening the movements. At 9, moisture in sand, the sodium carbonate did not incresse the moisture immediately around the de- posit. An examination of the data from the entire series pre- Scented in the six taodles shows that the amount and speed of salt tHrenslocation increases with the increase of moisture content up to a certain point after wnich other additions have little effect; that there is a moisture condition where the maximum amount of moisture is drewn arounc the salt and at all hizher moisture con- tents this property becomes lost; that the texture of the medium has but little effect in causing wide variations in salt and weter movements; and tnat salts vary in their moving power, in this case, potassium chloride bein= a much more mobile salt than sodium cerbenate. Theoretic#l consideretions of these facts lead one to believe that tne reesons underlving the incresse in the amount and Speed of movement up to a certain maximum point, are to be found in the solubilities of tne salts. It is a tenerelly recoznized fact that soluble sslts will go into solution fast at first, but <«s the concentration of the solution incresses, the rate of solution de- creases. Then in tre soil containing but 0.5% of water the total amount of salt really in solution is small, as compered with the The liovements Inches : Silt Loe from ‘After 10 days At Salt #reezing| Moisture Layer Point Content Lowerins 4 , 0.000 17.24 3 050 17.30 2 180 17.48 1 - 840 17.22 1 2750 17.34 2 £20 17.50 3 ~102 17.41 4 e000 17.08 4 ' Q.000 18.02 3 «000 17.96 2 — ,008 ~~ «17.84 1 2529 17.60 1 © 642 17.71 ra eO10 17.86 3 000 17.91 4 0000 17.89 oN em 8 ee al ‘ther cause lve more hat us it nm the ‘reat .on, iter, ma- it it ole rence, ,Lons 3 a um re- Jonate L206 total amount in solution with the soil at 370 moisture. And so, in the latter case, more salt being active, a sreater potential is crested, snd the relation follows the lzw of mass action. Greater movement S of salt sonseyuently take place. low, further adcitions of moisture, ao not incresse the total movement, because probably the lower percent was sutficient to completely dissolve the salt, and really all the added water does is to cilute the diffusin: solution so that its rate is slowed down even when more contacts have been rrovided. ‘WUhis is tenable from the fact that the movement of salt from a stron concentration to water is sreater than the same movement from a weak concentration. ‘thus it Seems reasonacle to assume tnat the whole phenomenon may be ex- plained unon the odzesis of solupilities. A corresronding line of reasonins may be emcoloyed in the explanetion of tne water pullins capacities . At law moisture contents, tie concentration around the selt deposit betomes ¢greet Since undoubte ly a saturated solution is produced. “his has &@ sirong sitractive force, cue to its increased surtace tension, and draws more moisture from the surroundins layers. ‘his water, in tne adjacent leyers, is however, held vitnr consideratle tena- re city and the s:tureted solution can obtain only a part of what it rectires. Sut, uvon the use of more waier more becores &V&llaole and movavle «rile the solution of salt is still s*turaved. hence, Q@ rtreater amount will be withcrawn in the gecond case. Additions of water teid to luecrease the ease with which the water moves earouna the soil psrticles, while it still produces a saturated solution vor the troctive avent. *®*inally wnen past the maximum tre salt becomes entirely dissolved en’ only a weak colution re- sults. Its oullins vnower is thus reduced. Since sodium csrbonate £1. is somevnat less soiudle tnan rotassium crloride, it continues to provuce 2 satursied solution for a lonzer lentth of time and exerts 1itS5 pullin™ power lonver wiien Ssens in accord with the LeRetSe ~he influence of texture seems nevli-ible, in most caseSe “he moistures used and comnsred ere rouvnly, multiples of t-e oritinnl “ycroscopie moisure found. ‘vort two inen ssetion for sslt tesated soil. and a ’ loner eiv.t inen seetion for water moistened soil. “he sslt trested soil conteined lo potsssium chloride sid wes made up to tre seme moisture convent «s the soil witr weter alone. or each water content trere wes provided a tube with the selt trect- ed and water treated soils in contact, end enother tube, in .tich q tee two comnonents of tre cxvstem were sersrated by ebout a = inch be) 5 0 air enncee After ctorins at 18°C Tor int-rvals oro, lu, and deys, tse tubes were tezxen cown in one ivich Sections, end cried. Lioicture ceterminctions vere mace on all Sections en? freezins point ceterminations run in a Tew in:tances «5 a check. ‘here were no selt moverents of course in the tvbtes vith air =p:ces, but the usvel movement took rlece in tre contact tubes. ithe moisivre contents glone usve becn “iven and are found in —“sble vw Io “here was a .airly ravid distillation of vayror scross the eir srace in sand, «t both morsiure contents, anc tra amount thet orssed ecross incre: Sed with tre time w:icn tre tudes were a tO stende osut at the end of 25 dars, tne meximum amount af Cl not Goue so, ena it is provsble ~ 1 of vapor trat could pacs over ra that the water would continue to callect in the s°1t leyer until 2 frec water is formed, vnich would tren flow bacx ss a strervme 27 In tubes with the salt in cornteect with the soil, th-re wes no movement or weter wriecr could pe csetected. It mirht he su -vezted nhovever, tnat a moverent, of venor took nltce between the two components, 9s bevrore, but the ineresse in tre selt lever, due to the condens: tion of tne vewor, wes taxen cere of by the continuity or the carill. ry water, . ich would allov = ren ju-tnent a- soon as one rart of the svstem heid more Water tren anotrer. AS a consecu°nce tren tnere vau nroneoly a streén of vs or passing from tre waver solution to the selt solution wit: its kivh surfece tension, in both cases. sut with en air sy ce, in one case, there “es no ensnce for 4 readjustment oF tne film, end so a svendy ine cresse wes recorded. in tne otner esse, ss was exrlsined sbove, tre roedjuctment thru the entire column wes vossible. his in Yact may exelsin ths n-enomena. It is werthy of note, that in te work of Bouyoucos(10) upon tre eftect of temperature in causinz moisture to nes seross this cir ensce, tnere vere only insicnificant movements recorded even betveen amplitudes of temmeraiure of 40°C. It is then vwrimrrily cue, in the present instence, to the rressure of « salt solution in one component of the system, wrich provides fora hicher surface tension, and a lowor venor pressure. ‘Znis in- equality then sterts the movenent of vanor from & roint of nhisn pressure to one o7 low pressuree The liovemen’ Lo] Inches Sand = from Orivtinel After . Salt 9 Layer Says | 6 5046 17.86 5 6.46 779 4 15.46 '7.91 3 S.46 |7.83 2 8.46 8.08 — 1 ' 8.46 7.99 | breek | 0 7.85 9.12 O 7.65 8.80 . | 6 6.46 8.01 - 5 6.46 8.16 4 8.46 7.99 3 8.46 8.17 2 8.46 & 04 1 & 46 7.61 solid | 0 7.85 7.92 0 7.85 7.69 f j= Ws tion 1d 1e bes WS e ‘eZ— ins en, |= Lose |= If The liovemen’ 1: J yon Inches Sand =#E from Oricinsel After |. 35 Salt a : . Layer _ Says | stion 6 6.46 37.86 id 5 5646 7.79 18 4 3.46 7.91 “abes 3 5.46 7.83 ’ 2 6.46 8.08 Se 1 8.46 7.99 {@2~ bre ek o O 7.85 9.12 Jes 0 7.65 8,80 | ms { oo r 6 6.46 6.01 5 68.46 8.16 M= 4 8.46 7.99 “en, 3 8.46 8.17 2 6.46 &.04 “ 1 b 46 7.61 solid 0 7.85 7.92 O 7.85 7.69 . | ‘ing t = II. The =ffect of Tenoerature upon the rate of movement of galt in soil. hie tnod-= Brass tubes of two sections,similar to those de- Scribed in pert three of the first section of this thesis, were used to meke the temperature studies. The short section contained soil with lw vcotessium chloride in solution, end wes at the same moisture content as the soil pleced in the long section which was moistened with water alone. The tubes were Sealed with rubber stoppers at each end, and kept at temperatures of O 15° end 65°C resvectively, for ten days. Sarnplinzs was performed as usual and both moisture and freez- ins point determinetions,made. The tompersture of eC, was mainteined by packing the tubes in a beth of melting ice. A thermorranh attached, showed that very small fluctuations occured. Anotner series of tubes were imnersed in @ water bath, which remained more nearly at 15°C, tran could have been cossible in the case of an air chamber. The hich tem- perature of 65°C, was maintained in an electric ‘ryins oven, with a part of tre heatins coils removed. Two tubes, of each moisture content were emnloved, to cuard azainst loss from leaks or otherwise. The data given in 'sble