TO CORRESPONDENTS.

New Zealand Herald, Volume XX, Issue 6750, 6 July 1883, Page 4

TO CORRESPONDENTS.

Enquirer, Auckland, writes:—" Please stale whether the present city of Auckland or Dunedn has the larger population."—According to the estimate of the Registrar-General for the month of May Auckland has 1311 more inhabitants than Dunedin, the numbers baing-Auckland, 2G.504 ; Dunedin, 25,463. Dunedin, however, has the opportunitj of being more populous than Auckland, as tie area within her municipal authority is considerably more than that with which Auckland has to deal. The boundaries of the city of Dunedin include an area of 1865 acres, while the present limits ot Auckland only Include 1632 acres. In other words, the area of the city of Dunedin is larger than that of Auckland by nearly the combined areacf Grafton and Wards.

A CoxsTAJiT Reader, Wellsford, write3:-''To decide a bet, would yuu kindly answer the following questions: 1. Which is the tallest and shortest peopl■; in Europe on an average ? 2. Does smoking stop the growth of the young ?"—l. The Laplanders are lower in stature than aay other European people, and the honour of being the tallest would probably be awarded to the Britons or Germans. 2. The use of tohicu'i by very young people is generally rejamed as decidedly hurtful.

CnAr.i.B3 Jones, Narracoorte, South Anstralia. writes : " Will any of tbe shares of the Auckland and Manukan Canal be offered in Australia, as I shnuld very much like to invest In that undertaking f" Arrangements for carrying out this important work ara not yet made, but it is one of the public worts which will hava to ba undertaken and completed in the course of a few yeara. When the work is taken in hand, it is not likely that a public company will be formed to provide the necessary capital. The Auckland Harbour Board will probably undertake and complete this work. In a few years this corporation will be very wealthy, and will be able, with the aid of borrowed money, to carry out such works more satisfactorily than a public compaiiy, having an eye only to big dividend!, would do. The first steps have already been taken in the matter, to have the Manukau and Auckland h irbours under the control of one board of management. The necessary information as to the revenue and expenditure of the Manukau harbour, endowments. &c., ara at present being collected, preparatory to the placing the two harboura under one management.

Schoolboy, Auckland, writes:—" w ould you kindly let me know if there is any difference between a mile square and a square mile {"—The difftrcnce is in the manner of expressing the same fact. The area embraced by either form of expression is the same ; but thero is a great difference between two Equaro miles and two miles square. Two mileisquare would represent «n ar*a equal to a atrip of country two miles long by one mile broid : but the phrase two miles square would mean a square v.'hose aides were two miles long, or equal to four square miles. The problem can easily bo demonstrated to any one by using a number of squares, each square to represent the square mile.

S. S. Stirling Castle.— J. J. B. (Remnera) writes in reply to the enquiry of A'auticus as follows :—The s.s. Stirling Cistle was tried on the Clyde on March 17th and lath, ISB2, when, in the course of a six-hours run, she gave an average speed of 18 IS knots an hour, and on six consecutive runs at the measured mile gave a mean speed of 18418 knots, equal to 21"3 miles per hour. The vesrel was built by Messrs. Johu Elder and Co.. Fairfleld, Govan, for Messrs. John Skinner and Co., and ran her trials with 3000 tons of dead weight on board. Her dimensions are—43o feet long, 60 feet broad, and 33 feet deep. Her register tonnage is 4300. She is furnished with three cylinder engines, working up to 8237 - l horse-power. The diameters of the cylinders are one 6U inches and two 90 inches each. The length of piston stroke is sft. 6in. The boilers are of steel, with 21161 square feet of heating surface, and 787 square f=et of grate area. The working pressure is lOOlbs. per square inch. The diameter of the propeller is 24ft. 4in.; pitch, 31ft.; and the number of revolutions per minute is G6. The vessel is built of steel. Her voyage from Shanghai to London, 1200 miles, was accomplished in 29 days 22J hours, including all detentions, the actnal steaming time being 27 days 23 hours. This i 3 quicker time by about seven or eight days than any run hitherto made. I am told she has exceeded her maximum trial trip speed when at sea, having done 19 knots for some time together. I may add that the expense and care to do such running is enormous, and the staff of engineers and firemen, &c has to be very large, and every appliance at hand for the efficient working of such powerful engine*!.