D.—2.

66

How far such advantage could be realized in practice depends on many considerations of detail, which, it would be out of place to attempt to dovelope here. The gain or loss would vary in amount with every line and with every train. But it may be said generally that with lines laid out and constructed as ours in New Zealand, with good rolling-stock in fair order, and considerable preponderance of descending tonnage, continuous gradients of 1 in 100 to 1 in 150 would be preferable to a dead level. The favourable condition's would exist to a large extent on the whole length of the central route. The average rise on the northern side is about lin 145 without any reverse gradient. Allowing for levels at the stations, 1 in 140 would be about the mean gradient, and 1 in 70 or 1 in 90 as the line may be laid out, would be the maximum. Conditions as favourable exist on the other side, except the section between the Waiau-uwha and the Hossack Saddle, and there would be a reverse gradient from the latter spot to the Clarence. The rising gradient of lin 50 is too steep to be used without break, and the wear and tear on this would probably neutralize the general advantage between the Red Post and Tarndale. On the whole, however, considering the certain preponderance of the descending tonnage, large or small, it may safely be affirmed that the route would not be more costly to work than a level line, and somewhat cheaper than the coast line by Cheviot, on which the heavy tonnage must rise several sharp inclines. In this point of view the Greenhills route would be greatly inferior to both, having the defects of the Cheviot route in a much higher degree. Assuming on the other hand that the tonnage would be equal in both directions, and that every gradient would be a practical loss, it is not true that a line with a high summit is necessarily worse mechanically than an undulating line. It is the accumulated amount of all the ascents that gives the measure of the loss. The sections of the central and Greenhills routes show an average rise going and returning of 2,850 and 2,386 feet respectively. But the central route being through leading valleys, its section shows very nearly the facts that construction would realize. That of the Greenhills route generalizes away a great number of small accidents involving many sharp reverse gradients. It tells nothing of the " fourteen distinct inclines in both directions of 1 in 25, three of 1 in 26, and ten varying from 1 in 30 to 1 in 50," nor of the "exceptional gradients which occur at the twenty-sixth mile," which Mr. Blair's report speaks. These would almost certainly make the total sum of the rises on that route greater than the one continuous rise on east side of the Tarndale summit. The Cheviot Hills route is much better, and no doubt its accumulated ascents are less, than that of the central route; but in this case the comparison of the highest summits in the two cases, 500 feet and 3,270 feet, vastly exaggerates the mechanical advantage of the Cheviot scheme on the supposition of an even tonnage in both directions to and from the centre of the lines. The concentration of seven gradients has been properly insisted on by Mr. Blair (in the same report and referring to the Greenhills route) as convenient and economical. This exists most perfectly on the central route, when the " ruling gradient" of 1 in*- 50 need rule only on one section between the Waiau-uwha and Acheron, if it be thought advantageous so to arrange it. A bank-engine, or one of extra power, might be exchanged at the bottom and top of that section for one of smaller size. On the Cheviot route this ruling gradient is found at both ends of the line and in both directions. The more powerful engines must be used throughout, or changed four times instead of twice, as on the central route. Judged by all these considerations combined, the mechanical conditions must be held to be superior on the central route in case the descending tonnage should be found to preponderate substantially, and little if at all inferior in any case to those of the coast route in its best form by way of Cheviot. The height to be ascended to Tarndale will not appreciably increase the cost of haulage as compared with that on the Cheviot route, and may cause an appreciable economy in the most probable case.

Wellington, Sattjedat, 9th Decembee. The Commission met at 10 o'clock a.m. in the Parliament Buildings. Captain Eobekt Johnson examined. 966. The Chairman.] The Commissioners are desirous of obtaining from you some information respecting the harbours on the northern portion of the Middle Island, and their connection with Wellington. 967. Mr. Thomson.'] What is your opinion regarding the value of Picton Harbour as compared with Nelson Harbour? —There is no comparison between the two harbours. While the Picton Harbour is almost unlimited in size, and will take any number of ships of any size at any time of tide, the Nelson Harbour is exceedingly small, tidal, and is shallow on the bar. 968. What is the distance in nautical miles from Wellington to Nelson Jetty, and from Nelson Jetty to Picton Jetty ? —From Wellington Jetty to Nelson Jetty direct via French Pass is 103 miles, and from the Wellington Jetty to Picton Jetty is 50 miles via Tory Channel. The shortest route from Wellington to Nelson is by the French Pass, which. Pass of course can only be taken with the tide, and for a large ship it is scarcely safe except in daylight. When the light is erected to show the end of the jreef, moderate-sized steamers can go through at night with safety —of course at proper state of the tide. 969. What size of vessel can at present go into Nelson Harbour daily with safety ?—Steamers of, say, up to 250 feet long, and drawing 18 feet, can enter and leave Nelson Harbour at top or near top of high water all the year round, except during heavy sea, which happens, say, about ten days in the year. 970. What size of vessel can go into Picton Harbour at present, daily, with safety?— There is no limit to size, and, with ordinary, care, there is perfect safety night or day at all times of tide. 971. Can vessels of the class which now go into Nelson Harbour always go through the French. Pass ? —Tes, alwaye.- A larger vessel can go through the French Pass than can work the Nelson Harbour daily. 972. With what size of vessels do you think it would be dangerous to go through the French Pass ? —They must be vessels of very large size. There is no difficulty as to depth of water. There is sufficient water for any ship in the navy. A steamer of 1,000 or 1,500 gross tons can go through the