LECTURE AT ST. PAUL’S CHURCH ROOM.

New Zealand Times, Volume XXXIV, Issue 5683, 17 June 1879, Page 3

LECTURE AT ST. PAUL’S CHURCH ROOM.

About 250 to 300 persons assembled at St. Paul’s Church-room, Tinakori-road, yesterday evening, to bear a lecture on the subject of “ Water” by Mr. S. H. Cox, F.C.S., Assistant Government Geologist. The Venerable Archdeacon Thohpe, who acted as chairman, briefly introduced the lecturer, stating that it was not only the wish of those who were acting with him that they should not alone raise funds to defray the expenses of the building in which they were assembled that evening, but also that instruction and amusement should be afforded to those who were present. The rev. gentleman said the lecture was an appropriate one. It was quite appalling to think of the state of the water in Wellington, as explained by Dr. Hector. He trusted that they would be told to-night what pure water was, and hoped that they might bo enabled to get such a very desirable thing at no distant date. He hoped that Mr. Cox would make his lecture as plain as he could, because very few of them really knew much of the subject of his lecture, simple though it might appear to be. He desired to thank the lecturer for coming forward, and also Dr. Hector, for having so kindly supplied all the necessary apparatus for the illustration of the lecture. .

Mr. Cox, on coming forward, was received with applause. He said the subject which he had chosen for his lecture that evening was “ Water,” because it was a subject in which they were all interested, and also because it afforded the beat start for subjects on physical science. Water, besides its ordinary form, might be found as rain, dew, clouds, ice, and snow ; and in its various forma it 'covered about three-quarters of the earth’s crust, the greatest development consisting of the oceans and seas. Most of the audience would recollect the floods which occurred about a year and a half ago at Motneka, by which one settler in particular lost a small patch of land which was famed as the garden of the Nelson province ; but he was consoled by finding that, although the soil had been washed away, some rich minerals were to be found in the shingle which had remained behind. The floods in the river Molyneux last spring were most destructive, and carried away all the bridges in its course except the railway one. It was interesting to notice that what wore at first only apparently silver threads of water would in a single night change to roaring torrents. Although rivers might be fed by springs, they were not of such common occurrence ; and even when they are fed from such a source it had been found that the springs were very sensibly affected by the rains. If they followed up several of the New Zealand rivers, such as the Eakaia, the Ashburton, the Waiau, and many others, they would find that rivers were derived from another source, and that they flowed from the faces of large bodies of ice, which were called glaciers,_ and in all cases these rivers would be found to issue from subterranean caverns in the ice. The water supplies which form the rivers do not commence at the glaciers, for if they were followed up—and iu many instances it was quite practicable—it would be found that eventually they would come on to snow fields, from which the glaciers derived their ice, and although travelling at a much slower rate than the rivers, still this ice was continually flowing towards the sea in precisely the same manner as the rivers did. The motions of the centres of the glaciers, like that of the rivers, were more rapid than the sides, and the tops were more rapid than the bottoms. The ice also flows more rapidly over a steep bottom than when it was comparatively level, and when the bottom was uneven it was found that the ice was also broken and uneven, just as the rivers were broken in the rapids. The lecturer then proceeded to illustrate the various phases of water, and demonstrated how it became condensed in a manner which elicited loud applause. The audience might wonder how it was -that the windows in a closed room became damp. The cause was to be found in the exhalations from the lungs, which, coming in contact with a colder substance, became condensed 5 and therefore the

expression, “ that tho room was steaming, was literally correct, especially when applied to ball-rooms. In the tropics, when the sun s rays struck the earth’s surface, the latter became heated, and tho earth in turn heated the air, which again reacted on the upper peril nof the water. The heated water coming into contact with the colder portion underneath, produced an aqueous vapour, which, on ascending a certain height, scattered to the north and south, and by this agency were the << trade winds” formed. When a north-west wind was blowing at Hokitika, it struck against tho Southern Alps, carrying its aqueous vapor with it, and then condensation ensues, clouds (either, and fine drizzling rain falls in the mountain valleys, and as the wind continues, heavy rains were produced in Hokitika. The winds proceeding still further onward, became deprived of their aqueous vapor, and so the hot winds which prevailed in Canterbury were produced. In Hokitika, the rainfall was 120 in. per annum, whilst in Christchurch it hardly averaged 40in. Ho expla; n;d how snow crystals were formed, and said it was wonderful to contemplate how symmetrical they were, nearly all of them being of a hexagonal form ; every particle of snow which fell having an attractive and repellent action towards every other particle. Coming to tho question of tho component parts of water the lecturer said that such a thing as pure water was not to be found in nature ; it could only be had when it underwent the process of condensation, such as that now generally adopted in the vessels belonging to tile navy and tho mercantile service. Bure water consisted of oxygen and hydrogen gases ; and the impurities consisted of the salts which were hold in solution. Hydrogen was about sixteen times the weight of. oxygen, and whilst the former was an inflammable substance, the latter was not so. When oxygon and hydrogen get intermixed together, an explosion takes place and air is formed. The lecturer illustrated, amidst loud applause, how water becomes decomposed by the action of potassium, taking, as he, did so, a small bottle which contained kerosene, and in which several small pieces of potassium had been steeped, and throwing them into tho water, produced combustion of the hydrogen, which being accomplished, decomposition ensued. The results of his experiments on Wellington water were not, ho regretted to say, of a very satisfactory nature. It required about '225 grains of oxygen to tho gallon to oxidise the organic matter which it contained ; a result which places our water, according to the classification of I)r. Tidy, in the fourth class of impure waters, and which proved it to be about 30 or 40 per cent, more impure than the water which was used in London. In conclusion, the lecturer gave a short sketch of the theories about glaciers amongst tho most scientific men, and stated that Professor Tyndall was of opinion that glaciers were formed by the different component parts flowing together, and getting into one mass by contact. He (the lecturer) was of opinion that too much importance was attached to the action of glaciers in tho configuration of the country, and in the formation of lake beds. The lecturer would now call upon Dr. Hector, as he saw he was present, to show the audience illustrations of glaciers which he had in the room, as that gentleman would be better able to explain them than he could, and retired amidst loud applause. * Dr. Hector, C.M.G., on coming forward, amidst cheers, stated that he was glad to accede to the wishes of Mr, Cox, more especially ns the Yen. Archdeacon Thorpe had been good enough to ask him to deliver the present or a similar lecture, but anticipating that ho would be away from Wellington, he had asked Mr. Cox to deliver the lecture for him, which that gentleman at once consented to do—with what result the audience were best able to judge that evening. He then showed some beautiful illustrations of Alpine and other glaciers by aid of the lime-light ; and also some lovely pictures of the Yosemite Valley—some of them towering thousands of feet high, but no glaciers had ever been formed there.

Mr. Izard moved a hearty vote of thanks to Mr. Cox for his interesting lecture, and one to Dr. Hector for his kindness in furnishing the appliances for the lecture, and also for his illustrations and explanations of glaciers that evening. * The vote was carried by acclamation.

During the evening Mr. Cox received valuable assistance in his experiments from Mr. Burton, one of the men employed at the Museum, and tho experiments proved highly successful in nearly every instance.