of it, so that some of the interior may be pulled out, the quality can also be judged. If the arm goes in easily the hay may be classed as light and the highest divisor used, but when it does not go far in the hay may be considered heavy. Round Stacks.-Measure the mean circumference between the bottom and the eaves in feet. Measure the mean height from the bottom to the eaves in feet and add one-quarter of the perpendicular height from the eaves to the point. Then the circumference squared multiplied by 0.08 multiplied by the height = the cubic contents in feet. Divide by 27 to obtain cubic yards, and use the following divisors to obtain tons. Not well settled Very compact . 13 11 . 9 Example.-A circular stack has an average circumference of 60 feet and a height of 12 feet. = Then 602 × 0.08 × 12 = 3456 cubic feet 128 cubic yards. Putting it at 11 cubic yards to the ton we get 11 tons 13 cwt. (approximately). Hay is sold by the ton in most parts of England, but in the North the basis of calculation is the Imperial stone of 14 lb. Again, in the neighbourhood of London it is sold by the load of 18 cwt. (i.e. 36 trusses weighing 56 lb. each); but when new hay is sold before September 1, the trusses must weigh 60 lb. 19 cwt. 1 qr. 4 lb. per load (see Tables of Hay and Straw Measure). To ascertain the contents of Straw Stacks.-Take the measurements in the same way as described for hay stacks. Taken on an average 18 to 20 cubic yards may be allowed to the ton for wheat, and 20 to 23 for barley or oat stacks. Straw is sold in London by the load of 11 cwt. 2 qr. 8 lb. or 36 trusses of 36 lb. each. In the provinces it is sold by the ton. To ascertain the contents of Corn Stacks.-It is a very difficult matter to arrive at the quantity of grain and straw in an unthreshed stack by calculations based on measurement. The crops should, if possible, be valued standing. The following table gives the comparative yields of grain and straw per acre :— AVERAGE WEIGHT AND YIELD OF CROPS If measuring of the stack is resorted to, the dimensions should be taken in the manner directed for hay stacks and the following tables used, but the results are not to be depended upon. Average weight of straw per bushel of grain. Number of cubic feet of unthreshed corn in stack to one bushel of grain. Example.-A stack of wheat measures 23 feet long, 12 feet wide, and 9 feet high. Find the number of bushels of grain, and the weight of straw. 23 × 12 × 9 = 2484 cubic feet. Putting it at 27 cubic feet to the bushel we get 92 bushels of grain in the stack. Taking the average weight of straw per bushel of grain as 112 lb. we get 92 cwt. or 4 tons 12 cwt. of straw in the stack. When grain is in the heap, the number of bushels may be ascertained by taking four-fifths of the cubic contents in feet. To ascertain the weight of roots in clamp. Find the cubic contents of the clamp in feet and use one of the divisors given in the following table, according to the kind of root. By Land Surveying is understood the art of ascertaining and representing the shape, character, and area of any portion of the earth's surface, as projected on a horizontal surface. Standard of Measurement.-Most surveyors in this country adopt the Gunter's chain, which is 100 links, or 22 yards, or 66 feet in length. Each link is, therefore, part of 66 feet, which is 7.92 inches. It was invented by the Rev. Edmund Gunter in the year 1620. There is also another chain in use by surveyors which is 100 feet in length, and is used chiefly by builders and many engineers. Advantages of Gunter's or the 100-link chain.—1. It is lighter than the 100 foot-chain. 2. In measuring to the nearest division there is less error than when using the 100-foot chain, because a link is shorter than a foot. = = = 3. It is more suitable for the working out of areas, because (1 Gunter's chain) (66 feet)" (66 feet)2 = 4356 square feet 18 acre. Also 10 chains 1 furlong, and 10 square chains = 1 acre. Advantages of the 100-foot chain.-1. Being longer than the 100-link chain, it is more conducive to accuracy when measuring long lines. 2. It is more convenient where calculations are required to be made in feet, such as is the case in builder's work, town surveying, and in fixing road gradients. It is sometimes called the builder's chain. 3. It has an advantage in the lining out of curves based on the degree of curvature (though the 100-foot steel band is generally used for this work). Land chains are made of the best cast steel wire or of iron, in different weights ranging from 4 to 9 lb., and costing from 7s. 6d. to 20s. The best chains should have welded and not open joints as they will then be less liable to stretch in use. In the Gunter's chain there is a brass tablet at 10 links from either end, at 20 links from either end the tablet has two teeth, at 30 links from either end three teeth, at 40 links from either end four teeth, and in the centre at 50 links from either end there is a round piece of brass. Care must be taken when reading the chain because the brass tablet which has two teeth may be either 20 links or 80 links, according as it is calculated from one end of the chain or the other. Every chain has 10 arrows or pins about 15 inches long, and made of the best iron or steel wire. They are pointed at one end and have a ring at the other. Besides the chains already mentioned there are the steel tape, steel band, 33-foot chain, and the 50-foot chain. The steel tape is used when very accurate measurements are required: steel tapes can be had of any length required-cost, & inch wide in case, 66 feet, about 18s. The steel band chain is of great use for accurate chaining in small surveys, as it is practically unalterable in length, because it has no links which can become stretched or bent. It is stronger and more durable than the steel tape. The 33-foot chain and 50-foot chain are useful in measuring sloping ground and offsets to a chain line. French Measures.-The decametre chain = 10 metres. The metre is nearly 10000000 part of the distance from one of the earth's poles to the equator and equals 39.37 inches approximately. The 20-metre chain 65.618 feet. = These chains are used in countries where the metric system obtains. It will be observed that the decametre chain is about half the length of, and the 20-metre chain (65.6 feet) very nearly the same length as, the Gunter's chain. All areas of land, except in those cases where land is extremely valuable, should be expressed in acres, roods, and perches. Example.-What is the area of a plot of land in the shape of a trapezoid, whose parallel sides are 15.21 chains and 12·42 chains respectively, with a perpendicular distance between them of 21.10 chains. (See Chapter I, Mensuration Rules.) There are 10 square chains in one acre, therefore by moving the decimal point one place to the left we get 29.14965 acres. To find the number of roods, multiply the decimal fraction by 4, thus •14965 0.59860 and we get 0 roods. To find the number of perches, multiply the decimal fraction by 40, thus •59860 23.94400 and we get 23.9 perches. ... the area = (say) 29 acres 0 roods 24 perches. To express roods and perches as the fraction of an acre, divide the number of perches by 160. Surveyors of experience know at sight how many roods and perches are represented by the decimal figures, and do not have to work them out by multiplying by 4 and 40, successively. TABLE FOR CONVERTING DECIMAL PARTS OF AN ACRE 2 Roods 3 Roods Perches 0 Rood 1 Rood 2 Roods 3 Roods '000 •250 ⚫012 •262 ⚫512 019 ⚫269 519 ⚫769 ⚫031 281 *531 ⚫037 ⚫287 *537 *044 ⚫294 ⚫544 *050 ⚫300 •550 9 *056 ⚫306 *556 ⚫062 ⚫312 ⚫562 |