June, 1923
I N D USTRIAL A N D ENGILVEERING CHEMISTRY
607
Effects of Treating Materials and Outdoor Exposure upon W a t e r Resistance and Tensile Strength of Cotton Duck’ By T. D. Jarrell and H. P. Holman BUREAUOF
CHEMISTRY, WASHINGTON,
D. C.
A
DECIDED deteriWaterproofing materials frequently promote deterioration i n the the cloth remains strong for for a long period of time.” 0 ati0n in th e strength of canuas exposed to the weather. strength of canvas I n general, the addition of pigments to waterproofing preparations The exposure tests here is beneficial, as they reduce the deteriorating eflect of sunlight without described, however, had which could not be attributed mildex’ Or backinterfering with water resistance. been begun a month berial decay was frequently fore the granting of this patobserved in an investigaent, and they were comtion on the effects of continuous exposure to the weather upon pleted before the patent came to the authors’ attention. The straight waterproofing treatments included the four the water resistance of treated canvas.2 This occurred when drying oils, which are commonly believed to “rot” canvas, formulas recommended in Furmers’ Bulletin 1157 (one slightly were used and also when the canvas had been treated with modified) and four of the eighteen formulas used in the materials ordinarily considered inert. Accordingly, a study weather-exposure tests reported by Veitch and Jarrell,2as well was made of the effects which waterproofing materials have as several others developed in the laboratory. While they are upon the tensile strength of cotton yarn when exposed to called straight waterproofing treatments to distinguish them the weather. One of the most striking facts thus shown3was from those to which pigment was added, several of them, those that the addition of burnt umber to a drying-oil treatment had containing asphalt or pitch, might be said to contain pigment, a marked preservative effect upon the strength of the treated the asphalt and pitch having a tendency to color the fabric and exposed yarn. This suggested the possibility that pig- and shut out the light. Three commercial preparations, none ments, when added to the waterproofing formulas developed of which contained pigment, were used for comparison with in the laboratory, might reduce the injurious effects of the the treatments developed in the laboratory. These comtreatments upon the strength of cotton duck exposed to the mercial treatments were used in the condition in which they weather. Further investigations were therefore started. were received and according to the directions accompanying Cotton duck was used, as the effects of treating materials them. upon yarn are not strictly applicable to woven fabrics. EXPERIMENTAL I n the investigations reported herein particular attention was given to a comparison of two waterproofing treatments, The solid treating materials were weighed out in the proper which in previous tests had caused rapid deterioration of proportions, mixed, melted, and poured into the solvent. canvas, with treatments which were identical therewith exWhen raw linseed oil, boiled linseed oil, or boiled linseed oil cept that they contained mineral pigments. Twenty-three and pigment were used, no solvent was added. Pigment pigments, including two asphalts, were used. was added at the rate of 1lb. to 1 gal. of the prepared solution, The effect of pigments in protecting fabrics from deterioraexcept in the case of Treatment A-15, in which the rate was tion by sunlight has received some attention from previous 0.5 lb. per gal. investigators. I n discussing the deterioration of doped aeroTwelve-ounce, gray, United States standard army duck,’ plane fabrics, Turner4 states that it was observed early in the cut from the same bolt into 15 by 28.5-in. sections, was used late war “that where paint was used on the doped fabric, such for all treatments. The treatments were applied with an as for identification circles on the wings, the fabric had not ordinary 2.5 in. paint brush and to’only one side of the canvas, deteriorated nearly so much as a t the unpainted parts.”’ with the exception of Treatment 20 in Table I, which was Turner, however, did not present any comparative data. applied to both sides. All treatments containing beeswax or Furthermore, Perrott and Plumb6 state that “as high as 20 paraffin were warmed slightly just before they were applied per cent of carbon tends to preserve the fabric (rubber gas to the canvas, and all solutions containing suspended matter mask), especially when exposed to sunlight.” This statewere kept thoroughly stirred during application. ment, however, was based on the performance of a single Four untreated sections and four sections, to which one of , sample. the base treatments used in determining the effects of pigThe use of pigments for protecting fabrics against the ments (Treatment 6 in Table I or A in Table 11) was applied, deteriorating effect of sunlight is covered, to some extent, were used as controls. in a patent granted to Gardner.fi In his specification the After applying the treatments and allowing them to dry, patentee states that he may “add to the ammonium phosphate solution (used to fireproof the fabric) from 2 to 10 per cent by each section was cut crosswise into two pieces, one 16 in. wide and the other 12.5 in. wide. The narrower pieces were weight of a pigment such as red iron oxide or carbon black; the purpose being to stop the light rays which affect the kept in the laboratory, while the wider ones were used in the strength of the fabric.” I n this patent the use of one or more exposure tests. The wider pieces securely attached to 12-in. boards, with their edges on the under side, were coats of dope containing aluminium powder is also specified, exposed to the weather in the open country near Washingsince, L‘dueto the high light-reflecting surface of the fabric, ton. D. C.. continuouslv from May 15 to November 15, 1 Presented before the Division of Industrial and Engineering Chemis1921. The’ boards on which the pieces of canvas try at the 64th Meeting of the American Chemical Society, Pittsburgh, Pa., placed were laid flat on trestles, so that the material would September 4 t o 8, 1922. be exposed to the rays of the sun throughout the day. At the 8 THISJOURNAL, 13 (1921), 672. 8 I b i d . , 16 ;1923), 23fi. end of six months the pieces were detached from the boards, 4 J . SOC. Dyevs Colourists, 36 (1920), 165. brought to the laboratory, dried overnight in an electric oven
were
6
THISJOURNAL, 11 (1919), 443. S. Patent 1,381,413 (June 14, 1921).
* Zi.
7
Count: warp 46, filling 34; ply: warp 3, filling 4.
INDUSTRIAL AA-D EhTGINEERINGCHEMIXTR Y
608 TABLE I-WATER
TR.EATMENT 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
RESISGANCE
AND
1-01. 15, No. 6
TENSILE STRENGTH O F COTTON DUCKSUBJECTED TO L A B O R A T O R Y WATERPROOFING TREATMENTS, WITHOUT PIGMENTS, A N D EXPOSED TO THE WEATHER FOR SIXMONTHS
TREATING MATERIALS'J Untreated control, 12 oz., gray, U. S. Standard army d u c k . . Amorphous mineral wax and beeswax.. ....................
..
................... Extracted wool grease, lead oleate, and
....
Proportion Used
....
85:15 65:20:15 65:20:15 65 :20:15 85:15 85:15 1 gal. 0.5 gal. 85:15 60:15:25 25:75 26375 25:15:60 25:15:60 85:15 60:40 25:75 25:15:60 25:75 25:75 25~75 25:15:60 25:15:60 75:10:16 30:10:60
Variation Tensile from Tensile WATERRESISTANCE Strength Strength of Strength AFTER EXPOSURE after Untreated of Funnel Spray Exposure after Unexposed Test Test (1-In. Warp) Exposure Canvasb Rating Kg. Percent Rating Kg.
0 5 8 1 6 6 2 3
9 9 10 9 9 10 9 10 10 9 9 10 10 10 10 9 10
0 8 10 9 8 6 6 9 9 10
io
10
.. .. ..
10
io 10 .. .. ..
38 14 17 23 12 12 6 11 -12 17 25 20 23 30 16 19 21 22 29 25 21 27 30 17 23 12 25 14 13 22 17
.. -63 - 55 - 39 -68 - 68 - 84 -71 - 68 00 - 34 -47 - 39
- 21 - 58
- 50 -45 -42 24 - 34 -45 -29 - 21 - 55 - 39 -68 - 34 - 63 - 66 -42 - 55
-
62
.. .. .. .. ..
55
....
.. ..
.. .. .. .. .. .. ..
58 58 63 60 58 60 59 58
Yellow petrolatum a n d petroleum asphaltd Yellow petrolatum lead oleate and petroleum asphalt. Yellow petrolatum' copper oleate and petroleum asphalt. Dark petrolatum, Leeswax, and pktroleum asphalt. Yellow petrolatum beeswax, and petroleum asphalt. .. Soft paraffin (scale'max) .................. 0 9 Beeswax 10 10 58 B Raw linseed oil (commercial) (no solvent used). . . . . . . . . . . . . . .. 58 e Raw linseed oil (authentic)f (no solvent used). 27a 56 Boiled linseed oil (commercial) (no solvent used) . . . . . . . . . . . 28 80 9 62 Boiled linseed oil (commercial kettle boi1ed)h (no solvent used) 28a 90 .. 55 a All treatments except as noted were applied in a mixture of gasoline and kerosene (3t o 2 by volume), using 2 lbs. per gal. b Tests made o i p o r t i o n s of treaied canvas kept in the laboratory, well protected from light, for the same length of time as the other portions were exposed. Tests not made on all samples because representative treatments showed little deterioration. c In coal-tar naphtha. 2 lbs. per gal. d Applied to both sidLs of duck. e The water dripped because the cloth broke upon folding. I Made in Bureau of Chemistry from Indian flaxseed. o Result of first test: upon repeating, the water dripped through rapidly, owing t o a break in the coating. h Claimed t o be kettle boiled for 8 hrs. in presence of burnt Turkey umber, red lead, and litharge.
....... .... ..........
......... ........ ................................................ ..............
a t 45" C., and then tested for their comparative water resistance by the modified funnel testlabeing rated on a basis of 10. The funnel test was repeated on all pieces from one to three times and the ratings were averaged. Many of the pieces were also tested by the modified epray test. After the laboratory tests for water resistance of the exposed samples were completed, the same pieces were used for tensile-strength tests by cutting each into five strips, 8 in. long in the warp direction and 11/4 in. wide, and then pulling out the warp yarn from both sides of the narrow strips until 46 threads, equivalent to a width of 1in. in the original canvas, remained. They were then placed in the constant-temperature and humidity room and allowed to condition a t 65 per cent relative humidity and 70" F. The tensile strength was determined at this condition by means of a standard type of tensile-strength tester. The results recorded in the tables are an average of five breaks in every case. The effect of the treatments upon the tensile strength of the exposed duck is expressed as percentage gain or loss, calculated from the tensile strengths of the treated and exposed samples and using the average strength of the exposed untreated samples as the basis of comparison. Table I includes all the laboratory treatments which contained no pigments (other than asphalt or pitch). Table I1 includes the treatments to which pigments were added, as well as the base treatments without the pigments. Table I11 gives the results obtained with the three commercial treatments. The weight of the duck was increased 25 to 30 per cent by all treatmepts in Table I, except those with raw and boiled linseed oils and Treatment 20. I n Treatment 20 the weight of the canvas was increased about 38 per cent, and would have been more but for the fact that the second application was made before the first had become dry. With linseed oils (Treatments 27 and 28) the weight was increased 8
THISJOURNAL, 12 (1920),26.
.... ....
.... ....
.... ....
..
..
60 to 65 per cent. Tho increase in weight from treatments in Table 11 containing pigments was 35 to 45 per cent, except in the linseed-oil treatments. When pigments were added to boiled linseed oil, the increase ranged from 70 t o 80 per cent, except in Treatment D-3, where it was only about 45 per cent. The linseed oil did not penetrate the cloth in this case because a soap solution had been applied to the canvas just before treating it.
DISCUSSION OF RESULTS With all the treatments in Table I, none of which contained pigments other than asphalt or pitch, the tensile strength of the treated canvas Hfter exposure was lower than that of t h e untreated canvas after exposure, and in many cases the deterioration was great. This general result differs strikingly from that obtained in the previous experiments with yarn,3 the treated samples of which in most cases showed a greater tensile strength after one year's exposure than did the untreated yarn after exposure. The reasons for this difference are not perfectly clear. Probably, however, the different method of exposure, resulting in subjection of the canvas to much higher temperatures than the yarn, and the different method of applying t h e treatments are important factors. Canvas subjected to treatments consisting of a mixture of 85 per cent mineral wax (Treatments 1 , 5 , 6, and 8 ) and 15 per cent of beeswax and that subjected to raw linseed-oil treatments showed decided deterioration, being from 63 to 84 per cent weaker than the untreated canvas after exposure. Yellow petrolatum apparently had a greater deteriorating effect than any other material used. When petroleum asphalt was substituted for beeswax in Treatment 5, a somewhat higher tensile strength was obtained, and as the quantity of asphalt was increased and that of the petrolatum decreased proportionately, the tensile strength increased. When coaltar pitch was substituted for petroleum asphalt, there was
INDUSTRIAL A N D ENGINEERING CHEMISTRY
June, 1923
609
TABLE 11-WATER RESISTANCE A N D TENSILESTRENGTH OF COTTON DUCKSUBJECTED TO LABORATORY WATERPROOFING TREATMENTS, WITH THE ADDITION OF PIGMENTS, A N D EXPOSED TO THE WEATHER FOR SIXMONTHS
AND WITHOUT
Variation Increase over from Strength Strength Obtained with Tensile Tensile WATERRESISTANCE Strength Base Formula Strength of AFTER EXPOSURE after Untreated after of after Exposure Unexposed Funnel Spray Exposure Exposure Test Times Canvas b Test (I-In. Rating Rating Warp), Kg. Per cent BS Strong Kg. 0 0 38 .. .. 62 2 84 ... 55 6 6 9 6.7 40 62 4-5 9 8.2 49 39 29 6 4.3 26 32 ‘8 .. 5.2 9 .. 31 18 .. 5.2 9 31 -ia .. 6.2 7 - 3 37 ‘si .. 9 7.2 43 .. 58 +13 9 6.5 39 66 + 3 9 8.0 48 09 2: 9 6.3 38 .. 59 8 .3 59 .. 50 32 8 6.6 55 10 39 + 3 9 7 . 2 54 .. 43 13 6.8 8 41 60 + 8 10 35 - 8 5.8 .. 33 9 13 5.5 .. 6.5 39 10 .. + 3 9 I6 32 5.3 .. 53 18 8 3.0 .. .. 2 7.8 47 6 .. +24 3.5 10 45 21 .. 9 2.7 16 58 5.3 32 16 .. 8 .. 9 -47 3.3 20 10 .. 27 0 2 -29 4.5 .. 2 1.7 10 74 .. 7 2 1.8 8 11 -71 .. 0 1.8 8 11 .. -71 ~
TREATMENT 0 A A- I A-2
A-3 A-4 A-5 A-6 A-7 A-8 A-9 A-10 A-ll A-1% A-13 A-14 A-15 A-16 A-17 A-18 A-19 A-20 A-21
A-2% A-23 A-24 A-25 A-26 A-27 A-211
B B-1 C
TREATING MATERIALsa Untreated control 12 oz gray U. S. Standard army duck .. Yellow petrolaturd and dbeswa; (No. 6 in Table I ) . Treatment A and dry yellow ochre.. Treatment A and yellow ochre ground in linseed oil.. Treatment A and dry Indian red.. .............................. Treatment A and Indian red ground in linseed oil.. Treatment A and dry Venetian Treatment A and Venetian red Treatment A and dry burnt sienna. Treatment A and burnt sienna Treatment A and dry raw sienna.. ............................. Treatment A and raw sienna ground in linseed oil.. ............... Treatment A and dry burnt umber.. Treatment A and burnt umber ground in linseed oil. Treatment A and dry raw umber.. ....... Treatment A and raw umber ground in lins Treatment A and dry Prussian blue.. Treatment A and dry dark chrome green.. Treatment A and dry artificial malachite green.. Treatment A and dry red lead.. . . . Treatment A and dry chrome yello Treatment A and dry lampblack Treatment A and Bermudez asphalt.. Treatment A and petroleum asphalt.. ..... .......... Treatment A and dry zinc oxide.. Treatment A and dry white lead.. Treatment A and whiting.. Treatment A and barytes.. Treatment A and kaolin., Treatment A and dry lithopone.. copper oleate, and petroleum asphalt (No. 22 in
............... ............................ ............. ...............
.
............................
........................... ...................... .................
..
................... ........ .......... .............................. .................................... .................................... ........ ............ ............................... ...........................................
-
..
+-
.. ..
+ + +
..
..
-
.. ..
.. ..
.
I
..
-
10 10 10 10
.. .. .. ..
30 52 23 50
- 21 +37 -39 +32, 42
...
1.7
...
58 59 59 57 62 59 62 55 58
2.2 c-1 22 D 8d 9 ... 1.8 D-1 9 40 10 + 5 D-2 9 1.9 .. 41 + 8 D-3 0 1.4 2 30 -21 D-4 7 1.7 37 - 3 D-5 9 - 5 .. 36 1.6 .. D-6 9 36 - 5 1.6 .. D-7 9 37 - 3 1.7 .. D-8 9 ii 1.5 33 13 .. D-9 9 1.9 42 10 +11 D-10 10 54 2.4 ...................... .. +42 58 2.6 8 D-ll .. .. 53 D-12 1.3 10 9 29 24 .. D-13 9 1.8 .. 40 + s D-14 9 2.3 51 .. .. +34 9 D-16 1.9 41 .. Treatment D and dry flake graphite.. ....... + 8 D-16 9 1.8 39 Treatment D and dry Prussian blue.. .. + 3 a Where pigment was used, i t was added t o the waterproofing mixture a t the rate of 1 lb. per gal. in every case, except A-15, in which pigment a t the rate of 0.5 lb. per gal. was used. b Tests made on portions of treated canvas kept in the laboratory well protected from light for the same length of time as the other portions were exposed. Tests not made on all samples because representative treatmknts showed little deteriorLtion. c Water-resistance test omitted because of defect in sample. d Result of first test: upon repeating, the water dripped through rapidly, owing to a break in the coating. e This treatment was prepared and applied as directed in Circular 24, issued September 15, 1919, by the Motor Transport Corps of the War Department.
.................
................. ................. .................
-
.. ..
-
..
+-
..
..
............... ...........................
a somewhat greater increase in strength. When lead oleate was substituted for a portion of the amorphous mineral wax in Treatment I, the strength was slightly increased, and the substitution of copper oleate for lead oleate caused a still greater increase in strength. Dark petrolatum and amorphous mineral wax9 have practically the same water-resistant qualities when 15 per cent of beeswax is mixed with them. Yellow petrolatum, which has a lower melting point and less viscosity than dark petrolatum, gave a much lower water-resistance rating when mixed with the same amount of beeswax than did the other two petroleum “greases.” When an excess of asphalt (75 per cent) was combined with either dark or yellow petrolatum, the water-resistanco ratings were the same, being increased to 10 in each case. The substitution of 20 per cent of lead oleate for the same amount of amorphous mineral wax in Treatment 1 increased the water resistance. Neither copper nor calcium oleate (20 per cent) was as effective from a waterproofing standpoint as lead oleate in formulas containing no asphalt. Apparently, there was no difference in water resistance when an excess of asphalt (60 per cent) was used. A noteworthy point in connection with these results is that whenever peg Amorphous mineral wax resembles dark petrolatum. a higher melting point and is more viscous.
It has, however,
troleum asphalt or coal-tar pitch was included in the preparations, the water-resistance ratings were high. Other experiments have shown that natural refined asphalts give similar results. Of the four materials used alone, beeswax gave the highest water-resistance rating (lo), Table I1 shows that pigments, when added to waterproofing treatments which are known to have injurious effects on canvas exposed to the weather, materially reduce such effects, In fact, many of the pigments used had a preservative effect, the strength of the treated fabric after exposure being greater than that of the untreated canvas after exposure. This effect of pigments in retarding the deterioration of waterproofed canvas exposed to the weather undoubtedly is due to the fact that they form a coating on the surface of the fabric, which tends to shut out the light. A somewhat similar effect is obtained by the use of bituminous materials. This might explain why treatment with preparations containing an excess (over 50 per cent) of asphalt or pitch usually left the canvas stronger after exposure than when it was subjected to other treatments listed in Table I. The fact that the treatments containing coal-tar pitch gave higher results than similar treatments containing petroleum asphalt was probably due to the darker surface coating obtained in the case of the pitch. 4 n inspection of the canvas indicated that the
610
INDUSTRIAL A X D ENGINEERING CHEMISTRY
petroleum asphalt, being more completely dissolved, had penetrated the fabric, leaving less color on the surface. Canvas subjected to the base treatment of petrolatum and beeswax (Treatment A) with the addition of various pigments was, after exposure, from 1.7 to 8.3 times as strong as canvas subjected to the base treatment alone. No great significance can be attached to the fact that two samples of apparently the same pigment, in one case dry and in the other case ground in oil, differ with respect to effectiveness in preserving the strength of the treated canvas. Aside from the possible effect of linseed oil, the pigment in two different samples might vary in chemical composition and physical properties. As a result of adding pigments to the linseed-oil treatment (Treatment D), six months’ exposure caused less reduction in tensile strength of the treated canvas than was shown by exposed canvas treated with the oil alone. This was true in every case, the strength after exposure being from 1.3 to 2.6 times as great as the strength of the canvas treated with boiled linseed oil without pigment. The addition of pigments to yellow petrolatum and beeswax resulted in increased water-resistance ratings. The addition of burnt umber to two preparations containing an excess of asphalt and having very high water-resistance ratings did not affect their ratings. The addition of pigments to commercial, boiled linseed oil had the general effect of slightly increasing the water resistance. Canvas treated with three commercial preparations free from pigments (Tablg 111) showed marked deterioration in tensile strength and also low water resistance after six months’ exposure.
Vol. 15, No. 6
TABLE111-WATER RESISTANCE AND TENSILE STRENGTH OF COTTON DUCK TREATED WITH THREE COMMERCIAL WATERPROOFING PREPARATIONS (FREE FROM PIGMENTS) AND EXPOSED T O THE WEATHER FOR SIXMONTHS 1
Treatment No. Untreated
I
I1 111
Tensile Variation Strength from WATERRESISTANCEafter Strength of Tensile AFTER EXPOSURE Exposure Untreated Strength of Funnel Spray (l-In. after Unexposed Test Canvas Warp) Exposure Test Rating. Ratinn Ka. Per cent Kg.. .. 62 0 0 3; - 87 60 0 0 (3 8 79’ 57 0 6 6 84 57 I
-
.
All treatments recorded in Table I1 which permitted the canvas to show after exposure a tensile strength of a t least 38 kg. (the strength of the untreated canvas after exposure) and a water-resistance rating of 9 or 10 by the funnel test are considered satisfactory for increasing the serviceability of cotton duck for outdoor uses. Since only such preparations as contained pigments come within this classification, it is probable that the treatments listed in Tables I and I11 would also be improved by the addition of the same pigments, and that, in general, the use of pigments in waterproofing treatments is beneficial. When added to linseed-oil treatments, pigments have more or less of a stiffening effect, sometimes making the canvas too stiff for purposes which require folding. Zinc oxide had the greatest stiffening effect, and lampblack and aluminium bronzing powder probably had the least. In commercial waterproofing preparations where there is a choice between light-colored or colorless and dark-colored varieties, the dark colors, such as buff or brown, will probably prove more durable.
Symposium on Hot Springs -A joint meeting of the Sections of Volcanology and Geophysical Chemistry of t h e American Geophysical Union was held at t h e Carnegie Institution of Washington on April 18, 1923, and was devoted t o a symposium and discussion on t h e temperatures of hot springs and the sources of their heat and water supply. Ten papers were presented. The temperatures of hot springs range all the way from those found in warm springs in t h e mountains of Virginia, some of which are only slightly above the annual mean temperature, up through boiling springs and mud pots such as are found in our western volcanic regions, t o fumarole temperatures of about 650” C., the highest temperature found in t h e Valley of Ten Thousand Smokes, Alaska, reported on b y E. G. Zies in his paper on “Hot Springs and Fumaroles of the Katmai Region.” E. T. Allen, in his paper on “The H o t Springs of M t . Lassen,” showed t h a t chemical reactions, such as could be inferred from t h e composition of the spring waters, are not adequate t o account for more than a very small proportion of the heat. Similarly, radioactivity, so far as i t can be inferred from the radioactivity of “The H o t Springs of Iceland,” described by F . E. Wright, is also insufficient t o supply much heat. T h e radioactivity shows no parallelism with the temperatures of the springs, as has been shown b y Thorkkelsson in Iceland, and by Schlundt and Moore in the Yellowstone. I,. H . Adams discussed “Physical Sources of Heat in Springs,” showing t h a t t h e forced flow of a fluid from a high to a low pressure through a porous ptug may develop considerable heatfor liquids, as much as 40 C. for 1000 atmospheres fall. I n fact, the passage of a n y material from a region of high pressure to one of low pressure will usually produce a rise in temperature. Such a process may be a source of heat in rock magmas. G. W. Morey, in his paper on “Relation of Crystallization t o the Water Content and Vapor Pressure of Water in a Cooling Magma,” showed t h a t similar heat effects could be obtained by the forced flow of steam. These physical sources of heat have not been considered heretofore, and geological observations are lacking t o indicate t o what extent forced flow is a factor in natural processes. There seemed t o be general agreement in the papers and in the discussion, however, t h a t the source of heat was in subcrustal rock magmas whether it escaped b y the familiar processes of conduction and convection, or whether the process of flow Elayed an important part. C. E. Van Orstrand, in his paper on Tem-
peratures in Some Springs and Geysers in Yellowstone National Park,” estimated from temperatures in deep borings t h a t most of the heat might be coming from a depth of about 8000 ft. Agreement was not so general as t o the sources of t h e water supply. I n the Yellowstone, as described by Van Orstrand, a considerable proportion of t h e water must be meteoric-that is, from rain and snow. The same is probably true in Iceland, where there is a large supply from snow fields and glaciers. Allen believes t h a t the probability is strong t h a t over half of the water in the springs of M t . Lassen is from such sources, and A. I,. D a y showed t h a t the water of “The H o t Springs of ‘The Geysers’ Region of California” is also mainly meteoric. On the other hand, i t was brought out in the discussion t h a t t h e amount of water which may be dissolved in a batholithic magma of the chemical character described by Morey may be sufficient t o supply small hot springs €or hundreds of thousands of years without any addition of surface water, and Morey also showed t h a t the conditions of crystallization of such a magma may yield water vapor under considerable pressure. It seems very reasonable to suppose t h a t a considerable proportion of the wate; in such places as “The H o t Springs of Vulcano and Kalamaki, described b y H. S. Washington, might be original magmatic water. This seems almost a necessary conclusion for some of “The H o t Springs of Southern Idaho,” described by 0. E. Meinzer. I t was shown very clearly in the paper by Meinzer t h a t there is no artesian source of water for many of t h e springs. It was also shown t h a t on the whole the hotter springs are the smaller, indicating t h a t dilution with ground water from moderate depths is responsible a t the same time for low temperature and large volume. These springs come through Paleozoic rocks, Cretaceous granite, e t c , and have no direct relation t o the Snake River basalts, which are now quite cold. A paper by Kirk Bryan on “The H o t Springs of Arkansas” was presented only by title as Mr. Bryan had t o be absent on field work. The publication in full of the papers and discussion is being considered. If they are so published i t will be possible t o add several other papers on other hot-spring areas of t h e United States, as well as communicated discussion, which will make this a valuable summary of t h e present status of our information on the subject. [ROBERTB. SOSMAN, Secretary of Sections of Volcanology and Geophysical Chemistry, American Geophysical Union.]
,
