HUNTER ON THE ANALYSIS OF SEA WATER. V.-Results of the Analysis of Sea Water performed on board H.M.S. Porcupine,” July 1869. By JOHN HUNTER,M.A. F.C.S. Chemical Assistant Qiieeii’B College Belfast. (Read December 2 1869.) COMPARATIVELY few researches have been carried on with the object of determining the precise amount and nature of the gases which are dissolved in sea water at any great depths below the surface. During the voyage of the “Bonite” in the years 1836-37 samples of sea water were colleet’ed carefully sealed up in flasks and brought home to be analysed in the laboratory of the College of France. &I Darondeau,* in a paper read April 30th 1838 gives the following table of the results of these analyses :-* Comptes Rendus t.vi p. 616. HUNTER ON THE ANALYSIS OF SEA WATER. 17 ~~ ! Composition of 100 vo~s Ill Density of gas. 8" to loo c. Yitrogen Oxygen. I Bug. 30th 1836. 1; ,',11;8 1025 *94 2.09 1 10.51% 83 -33 6-16 Pacific Ocean. . } 50k. 1027 *02 2.23 18 *06 71 -05 10 -09 Mar. 19th 1837. {s'yr1025 *45 1.98 13.9'7 80 -50 5 -53 Bay of Bengal. } 1143K. 87 18E. { 1026 *63 3-04 58,15 38 *50 3 -29 May loth 1837. surface 1026.11 1-91 13-32 80.34 6 -34 Bay of Bengnl. } 18 ON. 85 32 E./ 300 1025-86 2.43 80'13 64 -15 5 -72 July 31st 1837. 1025-7'7 1-85 12-46 77 -70 9 -84 24 55. 52 Indian Ocean.. } 0E.1 {si:r1027-39 2 75 34-92 55 -23 9 *a5 Aug. 24th 1837. }1 30 40 '. 1 Atlantic(South) 4'7E./{400 1027.08 2-04; 28-82 67 *01 4 *17 The surface waters were all perfectly transparent but those collected from a greater depth contained white flocculent par-ticles.The amount of gases held in solution was determined by boiling the water in a flask and collecting over mercury. In conclusion M. Darondeau states that the total gas in sea water is less near the surface and the difference in amount in-creases considerably with the depth. The gas from the deeper water contains more carbonic acid than that from the surface but this resuIt may have arisen from the decomposition of the flocculent matter previously mentioned. A few experiments were performed on board the "Bonite" with the following results :-Pacific Ocean.-September l2th 1836. Lat. 16' 53' N.; long. 118' 13' E.; depth 380 fathoms.100 C.C. of the water contain 1-62 C.C. of gases. &'ear the Philipyhe Islands.-November 21st 1836. Lat. 18" 22' N.; long. 132" 13' E.; depth 300 fathoms. 100 C.C. of the water contain 2-20 C.C. of gases and 100 C.C. of surface water 2-27 C.C. Chinese Sea.-November 29th 1836. Lat. 18" 0' N.; long. 117' 30' E.; depth 300 fixthonis. 100 C.C. of water contain 3-89 C.C. of gases. On the coast of Algiers M. Aimkt examined the amount of air contained in sea water from various depths and concluded * The carbonic acid in this experiment is uncertain. t Ann. Chim. Phys t. 2 p. 535. VOL. XXIII. C HUNTER ON THE ANALYSIS OF SEA WATER. that either none or only a very small quantity was dissolved. Water from 65 metres gave oiily from 0.01 to 0.02 of its own volume of air and from 1249 and 1606 metres no air or at least only a few bubbles.According to Bischof" 10,000 parts by weight of water con-taiii :-Observer. Mediterranean . . 1.1 by weight of carbonic acid-Vogel. Atlantic . . . . .. . . 2 3 97 99 99 English Channel 2.3 9 9 9 9, The same .... 0.77 , Bischof. Some observatiom indirectly connected with this subject were made bp M. Aim&? on the nature of the gases evolved by marine plants. He found that algae give off carbonic acid in the dark and decompose it under the influence of light. A. Hayest observed that there is more oxygen in surface water than at depths of 100 to 200 feet. M. Morreng made a series of experiments during the years 1836-37 on the quantity of gases held in solution by sea water at different Reasons of the year.He found that sea water dis- solves less air than fresh water that the latter gives off more in proportion of the contained gases on boiling and that the carbonic acid constitutes froin 9 to 10 per cent. of the gases. If the sea be agitated and exposed to diffuse sunlight the quantities of oxygen nitrogen and carbonic acid are capable of great variation. The oxygen and carbonic acid are in iiiverse proportion to each other but the iiumbers are not identical and do not form a constant sum. In consequence of the quantity of dissolved gas being much greater on a fine day we have the oxygen varying from 53-66 to 29.70 per cent. but in ponds and near the sea-shore these limits are increased to 20.78 and 76.04.The principal determinations of the composition of the air over sea water have been made by M. Lewy,ll who found during a voyage to Copenhagen that the air over the sea varied more than that over the land in proportion to the different * Chemical and Physical Geology i 113. t Poggendorff's Annal. Ix 404. 2 Sill. American Jour. 1851 p. 421. 5 Ann. Chim. Phys. [ti] xii 5. 1) Ann. Chim. Phys. [3] viii 125 and [3] xxxiv 5. HUNTER ON THE ANALYSIS OF SEA WATER. solubilities of the gases. Mr. E. T. Thorpe," in a valuable paper read before the Chemical Society concludes that the sea does not increase the amount of atmospheric carbonic acid but that the air over the sea contains proportionally much less car- bonic acid than that over the land.It will be seen from these abstracts that very little has been done towards the investigation of the gases contained in the ocean at any great depth and that the various experiments made with this object have not by any means yielded identical results. During the month of July 1869 I was engaged on board Her Majesty's ship ''Porcupine " in analysing some samples of sea water brought up from great depths. The specimens of water were procured by means of a large brass tube attached to the sounding line. This tube had two carefully fitted valves placed in it one at the upper end the other below but both opening upwards so that when the instrument was descending the water flowed freely through it but on proceeding to draw it up the pressure of the external water closed the valves and the sarnple of the last water which had entered the tube was secured.The method worked perfectly except when the sounding line came up at a great angle in which case the valves seemed not to hold in quite so well as when the line was brought up perpendicularly. Having got the water on board one portion of about 800 C.C. was placed in a flask and the gases determined by boiling ac- cording to the method of Dr. Miller. In every case the total gas was divided into two portions so that duplicate experiments could be obtained. The amount of organic matter in two quantities of water of 250 C.C. each was observed by Dr. Miller's process,? and the specific gravity was taken with great care by means of two or three instruments.It will be observed that the tables consist principally of two sets of experiments made on waters taken from the bottom and intermediate depths in the same locality. In both of them the bottom water was muddy and the succeeding specimens quite clear. In the second series the quantity of dissolved gas was very great so that on a slight eleva4tion of temperature it began to escape. It is to be regretted that I had not more opportunities of examining surface waters but this was un-* Chem. SOC.Jour. [2] v 199. t Chem. SOC.Jour. [2] iii 122. c2 HUNTER ON THE ANALYSIS OF SEA WATER. avoidable as the number of intermediate waters brought UP required coiistaizt attention and had to be analysed as soon as possible.With regard to the composition of the gases the carljonic acid was found in each case to be in greatest quantity at the bottom; it then diminished a certain amount and re- mained pretty constant until within about 100 fathoms of the surface when it diminished still more. The specific gravity of the bottom water is rather less than that of the surface in the first series while in the secoiid the two are identical. The amount of organic matter is about the same in bottom and surface water. In every case where a specimen of water was brought LIP the temperature of the wat'er at that depth was ascertained and the volumes of the gases in the folloTving tables are reduced to those temperatures and 760 inin. Fivst Series.Lat. 47" 39' O" Long. 11" 33) 0". July 23rd 1869. Sp. gr. of Cornljosition of 100 vols. Depth bottom Sp. gr. Grms. oj Total of gas. in Temp. and of oxygen gas in fathoms Fahr. interme surface for 100 c.c diate water. 250 C.C. :arbonic Nitrogen. Oxygen. waters. acid. -~___-~-2090 36 4" 1027 -3 .027 *5 *0016 2 80 35 -92 43.54 20.54 1750 36 *8 1027*5 .. -0012 - 34 *lo 45 *20 20 -70 1500 1250 1000 37 -2 37 -7 37 -8 1027 *5 1027 5 1027 *5 .. .. .. -0017 -0015 *0010 2 .87 2 *go 2 .60 31 .$6 32 .OO 30 *lo 48 -04 47 '74 49 *20 20 *20 20 *26 20 5'0 750 500 41 -4 47 .a 1027 3 1027 -4 .. .. '0006 .oo 10 2.20 2 *so 28 -62 28 -10 49.44 49 *70 21 -94 22 *20 250 50.5 1027.4 .. -0014 2 -70 25 *I2 52 '42 22 *46 HUNTER ON THE ANALYSIS OF SEA WATER 21 Second Series.-Lat. 4P 12) O*' Long. 12" 52' 0'). July 27th. ~~ Ip. gr. of arms o Total Compoeition of 100 vols. Depth bottom Sp. gr. oxygen gas in of gas. in Temp. and of for LOO C.C. nterme of fathoms. Fithr. diitte water. Of water. Jarbonic 0xygen. Sitrogen. waters. water. acid. -__-_ .- 862 39 -8' 1027 *5 027 '5 -001 3 .5 48 -28 17.22 34 -50 800 42 -0 1027 *7 .. '001 28 33 75 17 79 48 *46 750 42 -5 1027 *5 .. .0012 28 31.92 18 i6 49 32 700 43 .7 1027 5 .. -0013 - 31 03 15 -31 49 66 650 44 .4 1027.5 .. - 2.4 30 00 19 80 50.20 600 45 -5 1027 5 .. -0003 24 28 31 20 14 51 52 5 50 500 46.4 47 4 1027 5 1027 5 .. .. *0009 *On14 2.6 22 29 *06 27 2G 20 -iO - 50 -24 - 450 47 6 1027 5 .. *0005 2.8 24 .i3 22.18 53 *09 400 48 5 1027 6 ...0014 2 *5 350 49.2 1027 3 .. .0015 300 49 6 1027 '.5 .. .0018 250 50 3 1027 .3 .. *0019 200 50 5 1027 *3 .. .0017 50 53 '4 1027 *A .. .0014 2 *2 - Miscellaneous Experiments. Grms. 01 Composition of gas in Bp. gr. Sp gr oxygen Total 100 vols. Temp. of of for bottom surface 250 C.C. water. water. of Ciwbonic Nitrogen. Oxygen. water. acid. 0 -I-- 49 -5 1026 -7 1026 .7 -001 -37 -88 45.63 16.49 -1027 7 .. -0002 -3 .27 59 63 37 *10 44 '2 1027.6 1027.7 -0(,21 2.2 24.85 57.02 18.13 -'0018 2.4 24.37 50.07 25.56 1027.6~ -After the reading of this paper Xlr. McLeocl expressed his opinion that if the absolute quantit,y of carboiiic anhy-dride or carbonic acid gas in 100 volumes of water had been given the results would then have been more comparable and the relation between sea water and ordinary spring water would be shown.The total quantity of gas in 100 volumes MADAN ON SOME POINTS IN THE of sea water was much less than he mould have expected and less than is found in ordinary river waters. Thames water he thought contained 6 volumes in 100 of the three gases together ; while the largest proportion of gas iu sea water according to Mr. Hunter was only 2-8 in 100. It had been stated that sea water brought from a depth effervesced like Boda.water; but that would seem to be almost an impossibility if the quantity of gas obtained was as low as 2.8. It was just possible that in collectiiig the water if there was any pressure in the tube it would open the upper valve aid allow nearly all the gas to escape; but he (Mr. McLeod) was not in a position to suggest a better apparatus than the one described.