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After quoting the latter part of the letter from out magazine of July, p.332, Mr Bradley proceeds thus: "As to the first part of the problem (namely, finding the longitude), I suppose few persons who have practised the Lunar method have any reason to doubt but that the computed distances of the sun and moon, &c. to every three hours as put down in the Nautical Almanac, are very exact. It appears to me that gentleman is not so well acquainted with the rules given in the Requisite Tables, or in the Nautical Almanac for 1772, for reducing the apparent distance of the sun and moon,  on account of parallax and  refraction, to the true distance, as he ought to be; as he asserts a very great improvement is made by Mr. Robinson, but has not shewn in what respect." 

Mr. Bradley then proceeds to give 160 actual observations of the distances of the sun and moon's nearest limbs, together with the altitudes of their centers. taken on the platform on the top of the Royal Academy at Portsmouth. Near 100 of these observations are disposed into the sets of 2, 3, 4, and 6 in a set, making in all 24 sets, and the longitude of the place is derived from each set, by Mr. Witchel's method. The most that any one set makes the longitude is z° 42^7[[?]]; the least is o° 52°. The true longitude is r° 6', the latitude 50° 48^7. Although we cannot give all the special matter in evidence, as we wish; yet we think enough is said to warrant Mr. Bradley's conclusion, "That seafaring [[?]] gentleman will be sufficiently enabled from hence to judge of the usefulness of this method, and of what may be expected from it when accurate sextants can be obtained."

Some Account of ROLLING CARTS and WAGGONS, as they are now built by James Sharp, of Leadenhall street, London, according to Two Acts [[?]] passed the last sessions of parliament, for the Amendment and Preservation of the public Highways and Turnpike-roads. (See the plate.) THE rollers are placed under the body of the cart or waggon, and run abreaft, or parallel, with each other. They are true cylinders of cast iron, two feet in diameter, and 16 inches broad, perfectly flat, without nails, or other projection, to injure the face of the road. The insides are filled up with strong plank, so as to appear, and have the strength of, a solid roller; and yet are hollow in the manner of a cask. Upon a Smooth and hard surface they are drawn as easily as narrow wheels; and it cannot be doubted but the frequent use of them will render the roads smooth and hard. 
The roughness or inequality of roads, occasioned by wheels too narrow, or broad of resistance to the cattle; and not friction, as some have supposed: for it may be demonstrated, that, upon the generality of roads, these rollers have less friction upon the axis than larger wheels. 
Some persons having objected to them on account of the lowness of the wheels, it is necessary to consider how far the objection is just.
It is allowed, that there are two advantages on high wheels, viz. their being levels lessening friction upon the center, while they stand perpendicular; and their having a large circumference. 
But these advantages are much overbalanced by inconveniences; and it may be easily proved, that loaded carriages with low wheels will be drawn with greater ease to the cattle, for the following reasons:
Because the great increase of weight in large wheels, when applied to heavy carriages, is of itself prodigious, and must always be considered as a part of the load, some of them weighing from 30 to 40 hundred weight.
Because, also, high wheels, though levers lessening friction upon the center, when they stand perpendicularly, are also levers increasing friction by lateral pressure, whenever the carriage passes upon uneven ground. And, lastly, 
Because high wheels require greater force to pass them over the usual obstacles of the road; the force of the animal being then applied in an horizontal direction, and great part of it lost in pressing against the obstacle. 
These circumstances considered, the balance will be found in favour of low wheels, 
1. Because they are both lighter and stronger.
2. Because, in general, they have less friction.
3. Because less force is required to surmount the usual obstacles of the road, the elevated draught being more nearly parallel to the line of ascent.
4. Because the animal can really apply more strength to the low than high

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