The Evening Star TUESDAY, MARCH 17, 1874

Evening Star, Issue 3453, 17 March 1874, Page 2

The Evening Star TUESDAY, MARCH 17, 1874

In order that our account of the approaching transit of Venus may bo complete as far as it goes, it is necessary that we should endeavor to explain “ Delisle’s Method. ” Our readers will remember that “ Halley’s Method” of determining the Sun’s horizontal parallax rondel's it • necessary that the apparent passage of Venus across the Sun’s face should bo observed from two stations—the one as far north, and the other as far south, as possible. Besides this, it is necessary that, in order that the time occupied in the transit may be found, the beginning and the end of the transit should be observed at both stations. As the transit of 1874 will occur in December, it is evident that the northern observation will have to be made under very unfavorable circumstances. The chances are that the weather will not bo all that could be wished at any of the northern stations ; while of course the Sun will reach, even on the meridian, only, a very low altitude, as it will be at that time of the year very far to the south. The most favorable southern stations as regards difference of time occupied in the transit are at or near the Antarctic Continent, but this is practically quite inaccessible; even if an astronomical expedition could succeed in effecting a landing on its rockb'ounji coastf, there would he but little reason to hope thal th‘e neces&Vy fcVser-

vations could be made in such foggy, snowy, and windy regions. It appears then, that though Halley’s method is an excellent one, there are, or may be so many drawbacks to its successful employment that it can never -be used fullest advantage. This fact led Delisle to devise a supplementary mode of attacking the problem. We propose to try to give our non-mathematical readers some idea of this method, and if they will take the trouble to clearly understand our somewhat homely illustration, they will then have little difficulty in grasping the principle on which this method is founded. Let us suppose

that two persons are sitting in an express waggon, which is moving very slowly along near the pavement opposite the principal doorway of the Provincial Government Buildings, the one -sitting on a seat placed in front of the express, and the other near the back. If* then a man passes rapidly northwards between the express and the doorway, it is evident that the man in the back part of the express will see the passerby fairly in a line with the south end of the doorway some time before the one in front will see him in a similar position. In other words, the apparent “ingress” of the passer-by on the doorway will take place sooner for the man at the back of the express by an appreciable interval of time, than it will for the one at the front. The same is also true of the apparent “ egress.” This is just what will take place in the case of Yenus, the Earth, and the Sun. The Earth is moving comparatively slowly round the Sun at a known relative distance, which we will call for convenience sake 7. Yenus is moving much faster, at a relative distance of 5. There will clearly be, as in the case of the express, a point on the Earth’s surface, where the whole of Yenus will appear to be fairly on the Sun’s disc sooner than it will so appear at any other point. There will also be another place, of course nearly opposite to the last, where the planet will be projected on the Sun's face later than at any other point. What is true of the ingress is true of the egress. Let

us now suppose the Earth to have been at rest, and that the longitudes of the two places where the planet’s ingress took place, earliest and latest respectively, have been ascertained, and that the time when it happened at each place has also been accurately ascertained : then we have all that is necessary to enable us to determine the

Sun’s distance from ns; for we know the.time.that Venus has taken to pass over a distance which bears the same proportion to the distance between the two terrestrial stations as five does to seven. We know, too, accurately, how. long it takes Yenus to go right round the Sun, consequently we know the total distance that it has to go ; for the short distance, found by the above method, bears the same proportion to the whole orbit as the short time does to the whole time; it is a mere matter of rule of three. The whole distance traversed by a planet, being thus known, geometers have no difficulty in finding the mean distance of the planet from the Sun, and if the distance of Yenus from the Sun can be found, the distance of the Earth is also known, for, as we said above, the relative distances of Venus and the Earth from the Sun have been aeonrately determined. Thus the problem is solved. It is true that we have supposed the Earth to be at rest, and Yenus to move at an equal rate

throughout its course, both of which suppositions are untrue j but then astronomers are quite able to make all proper allowances for these circumstances. They present, in short, no difficulty. Of course, if two observations were to be made as the planet is moving off the face of the Sun, these would answer the purpose just as well as those made at ingress. The advantages of this method then, are, that only one correct observation requires to be made at one station instead of two, as for Halley’s method. It is plain that there is a far greater chance that the weather will allow one observation to be made, than that it will be fair both at the commencement and at the end of the transit. The disadvantages are, that the exact time at the place where the observation is made

must be known; to ascertain this often a matter of no small difficulty. In Halley’s method it is onlynecessary that the duration of the transit should be known, so that if the clock used goes pretty well, it does not mutter at all whether it shows right or wrong time. Dunedin would be a pretty good station for both methods, and we think that the Government might well spend the small sum that would be required to get the transit properly observed. It would be very

vexing to scientific men throughout the world if it should happen that bad weather prevailed at the stations in our vicinity, while we in Dunedin with clear sky and fine weather had no means of observing the phenomenon. This is not likely to be the case, but it possibly may so happen.

To-day, being St. Patrick’s Day, was observed as a holiday by several of the Government _ departments. Shortly after twelve last night the Artillery Band paraded through the streets playing popular Irish tunes. , It is intended to call a public meeting of the citizensnext week to consider the advisability of petitioning Parliament to curtail the powers of the Water Company, or, failing that, to urge upon the Corporation to construct new water works. I he telegraph wire is being carried by Messrs Cargill and Anderson from the Roxburgh office to their homestead, Tevidt Junction. This and the meat-preserving works station a$ Kakanni, , aid, wei believe, the only private o&c?s in th& ’ Province.

We are informed that the premises at present occupied as a biscuit factory by Messrs Hudson and Co. have been secured by the Turkish Baths Company. Possession will be obtained in about ten days, when operations will be at once commenced to prepare the baths, which will be pushed on to completion without delay. The shares of the company are nearly all taken up, and. the promoters of the undertaking feel certain of success. • A very sersous charge is made against some of the Auckland representatives at the late Intercolonial Rifle Meeting. The Victorian Government lent them new rifles, and it is skid that they removed the barrels and substituted those of their ordinary weapons, fixing the new barrels on the old stocks. The fraud was discovered by the armorer taking one of the rifles returned into store to piece?. It was then found that the number on the stock and that upon the breach of the barrel did not correspond. This cause inquiry, and the little swindle was found out. “ Aurora Floyd,” and “ Lady Audley’s Secret ” were repeated at the Queen’s Theatre last evening to a pretty numerous attendance, considering the boisterous weather. In the first piece Miss Stephenson as the heroine, and Messrs. Searle and Glover as “ the Softy,” and Jim Conyers, the horse-trainer, respectively .acted very well throughout and were frequently applauded. “The Rose of Killarney” is announced for this evening. The programme for the race week will ba a capital one, consisting of the burlesque of “ The Fair One with the Golden Locks,” and a pantomime. Mr Kemp is engaged in painting now scenery for the burlesque. A rather novel way of. ejecting obnoxious tenants was, according to the ‘ Tuapeka Times.’ lately adopted by a landlady at the Teviot with great success. After all legitimate means had failed, she tried the following strategy:— Whilst her lodgers (they were man and wife) were locked in the arms of Morpheus, a flood of water, which had been stored in the attic, was let in upon them from the region above the bed. Imagining that a second deluge had set in, or that the Molyneux had overflowed its banks in a mighty flood, they, in the shortest possible time, managed to clear out as for their lives, to the no small delight of the landlady, who had watched the result of the manoeuvre with considerable anxiety.

The laying of the rails is progressing upon the Waihola section of the railway. A commenceipent was made at the south end—the site of the bridge across the Waihola River—and about half a mile has been completed. Mr Watson is making very satisfactory progress with his contract for the erection of the railway bridge across the Taieri River, behind the Reliance Hotel. The sixth cylinder is almost down to its proper depth. Only four others have now to be driven, when Mr Watson will be able to remove the machinery, and make a start with the other and larger contract —the bridge across the Waihola River. The ‘ Bruce Herald, 1 from which we take the above particulars, remarks that although some little dissatisfaction was-expressed at the delay in letting these contracts, it is fully expected that hot! bridges will be completed as soon as the tunne through the Chain hills, so that no delay wil be caused by them in the final opening of the line, A heavy laud slip took place on the railway works jit the rock cutting near Clarks Flat, Waitahuna road, a few days ago. It is estimated that from 600 to 700 tons of earth and rock fell on the Hue of railway! An Invercargill correspondent of the Queenstown paper writes “ The' Superintendent recently electrified us at the Governor’s luncheon by stating that t}jg forests in Southland would pay the National D.ept, Of course, as

might have been expected, the Tay street party (as the Rsidites are called) ridiculed the statement ; whilst the Dee street party (the Macaudrewites) adopted a negative style in argument. Well, whether the calculation be right or not, we all at any rate feel the advantage ol the employment the numerous sawmills offer. It occurred to me, however, to ascertain if possible the average production of an acre ot good bush, and I went to considerable trouble to find this out. Southland proper has 300,000 acres, and Stewart’s Island 500,000 acres of forest. The comparative terra incognita west of the Waiau river contains bush"that fully equals anything on the coast of the Islands. I know this from authentic sources ; and had the Government accepted the red birch for sleepers, there would now have been two or three sawraills.iu full operation between that point and the Big River (Patupo). Taking Southland and Stewart’s Island alone, my figures cannot approach the Superintendent’s, although the results are in millions ; but if the area of bush land west of the Waiau is approximately estimated, the Superintendent’s statement is hearer the fact than imagine.” The ‘Evening Post’ blames the Agent-Gene-ral for the mismanagement which has charac terised the recent dispatch of immigrant ships to the Colony, and says:—“ One instance of his gross mismanagement has been related to us on most reliable authority, and it in souie

measure accounts for the great mortality amongst children on the voyage out. When a ship is taken up for the conveyance of immigrants, the Agent-General simply informs the owners of the number of statute adults it is proposed to send in her. Thus in the case of the ship Rakaia, for instance, the Agent-Gene-ral may intimate to the New Zealand Shipping Company that 300 statute adults will be sent by her. The Company provisions the ship acbut probably after sailing the captain be has, say, 150 children on board. Looking it jtds store list be finds that no provisions adapted to the consumption of children have been placed'onboard, arid aegordiugly the poor little ones have to struggle to exist on biscuit, preserved meats, and salt meat,, It is no wonder that many of them succumb who would probably be able to thrive well on board if food suitable to their age were, as it well might be provided. If instead of reducing children by official process to statute adults the Agent-General would inform owners how many children and hpw many actual adults he propose! to ship, we believe the owners would gladly put on board a supply of food suited to the ages gf the children, /jnd that the rate of mortality wquld thijs be very muph reduced. VV e have heard of pne case, where there were upwards of 120 children m bpard a ship,’‘and not a pound of sago, except a small quantity amongst the medical comforts for hospftaj. It is no wonder the children die/'