MEASUREMENT. 234 MEASURING WORM. poop, forecastle, deckhouses, between decks, etc. From the total so obtained the fol- lowing deductions are made: (1) Space exclusively occupied by the crew and the storage of their clothing, etc.; provided that this space does not exceed 20 per cent, of the remaining tonnage of the ship; if it is greater than 20 per cent, the excess is to be considered as part of the tonnage .space. (2) Space framed in above the upper deck for machinery or for ailniission of light or air. (3) In vessels pro- pelled wholly by .sails, any space set apart and used exclusively for stowage of sails, if not exceeding 2% per cent, of the tonnage of the ship. (4) Any space used exclusively for the accommodation of the master. (5) Any space used exclusively for the working of the helm or of anchor gear or for keeping charts, signals, instruments of navigation, and boatswain's stores. (G) Space occupied by donkey engine and boiler if connected with main pumps of ships. (7) Double bottom when not available for cargo, stores, or fuel. (8) Actual engine room and fire-room including shaft alley, but omitting all space not occupied by engines and boilers or necessary for working them. When the actual engine and fire rooms occupy in paddle vessels 20 to .30 percent, of the gross tonnage the deduction is to be 3" per cent, of gross tonnage ; when the engine and fire rooms occupy 20 per cent, or less the deduction may be 37 per cent, of the gross tonnage or I'o times the actual engine and fire room space, the option resting with the Board of Trade; when the space occupied by the propelling macliinery, etc., exceeds 30 per cent, of the gross tonnage the deduction to be made is 37 per cent, of it or IVj times the actual engine and fire room space, the option remaining with the owners. In the case of screw steamers when the space occupied by the machinery and boilers is 13 to 20 per cent, of the gross tonnage the deduction is 32 per cent, of that tonnage; when the space occupied is 13 per cent, or less the deduction is .32 per cent, of the gross ton- nage, or l'} times the actual space, the option remaining with the Board of Tiade: when the space occupied is 20 per cent, or more the de- duction is 32 per cent, or l^'i times the actual space, at the option of the owners. The total additions and deductions to the ton- nage space having been ni:i(le. the capacity in cubic feet so obtained is divided by 100, and the result is the rci/inler lonnaric (or net register tonnage) of the ship. The gross register ton- nage is obtained by dividing by 100 the total capacity of the hull and deckhouses without de- ductions. When. OAving to the presence of cargo or other reason, it is impracticable to measure a vessel ns heretofore described, the tonnage is deter- mined as follows: Pas's a chain around the hull at Iho midship section and measure the length under the bottom from the upper deck at one side to the upper deck at the other. Call this the girth. .Add one-half the girth to one-half the main breadth; square the sum so obtained and multiply the result by the length of the .ship from outside the stem to outside the stern post; multiply this product by .OOIS for wooden ships and by .0021 for those built of iron or steel. By the act of Congress of May 0. isri4 (taking effect .January 1, 18(5.5), the Tnited States adopted the English system with slight changes in details which are thought to conduce to greater accuracy. This act lirs been supple- mented by several others, notalily that of ilarch 2, 1895, which makes the American practice almost identical with the Knglish; indeed, the wording of the law is generally the same through- out. In measuring, however, the I'nited States law divides vessels into six classes according to length and the divisions in each class for meas- urement of transverse areas are: In Class 1 (vessels under 50 feet length on the tonnage deck) the length is divided into 6 equal parts; in Class 2 (vessels 50 to 100 feet long), 8 equal parts: in Class 3 (vessels 100 to 150 feet long), 10 equal parts: in Class 4 (vessels 150 to 200 feet long), 12 equal parts; in Class 5 (vessels 200 to 250 feet long), 14 equal parts: in Class 6 (vessels over 250 feet long), IG equal parts. The method of measuring and conipiting net and gross tonnage is the same as that al- ready described. The British system of measurement has also been adopted by the following countries on the dates given: Denmark, 18G7; Austria-Hungary, 1871; Germany, 1873; France, 1873: Italy, 1873; Spain, 1874; Sweden, 1875; Netherlands, 187G; Norway, 187G; Greece. 1878; Russia. 1879; Fin- land, 1877; Haiti, 1882; Belgium. 1884; Japan, 1884. In some of these the allowance of deduc- tions, particularly that for propelling machinery, dilTers somewhat from the British rule. BiBLioGR.vriiY. For furtlu'r information, con- sult: Instructions to Measuring Surrcgors (Lon- don, 1891) ; Lloyd's Seaman's Ahnaniic (London, 1893) ; Revised Statutes of the United States, Section 4153; and the Suppleuicnta to the lie- vised Statutes, also the Statutes at Large for 1895. The Instructions to Measuring Surrcgora gives all the British acts complete with instruc- tions for carrving them into effect, detinitions, etc. MEASURE OF DAMAGES. See Damages. MEASURES. See Weights and Measubes. MEASURING WORM. Any one of the larv:c of I lie li'[ii(lnptcrous superfamily Geoniet- rida", also calli-d l(io]H'rs. The group is a vei"y extensive one and consists of fragile moths willi comparatively large wings. The caterpillars are long and slender, with only one pair of abdominal feet placed upon the ninib segment of the body. There is also an anal pair of feet which function as claspers. The measuring worms walk by mov- ing these two pairs of feet up to the thoracic legs, so that the body forms a large loop, giving the insect the appearance of measuring the sur- face ipon which it is walking. It is this habit which has given the popular names 'loopers.' 'inchworms,' etc. (see Gkomkthid Morn), and the. scientific name Geometrida- to the insects of this groiip. Measuring worms feed upon the leaves of plants, with the exception of a few which bore into seeds. They are usually protec- tively colored so as to resemble twigs, and they have the attitude when at rest of holding the body stiff and erect at an angle from the main stem of the plant, so that they almost perfectly resemble twigs. 'I'he individuals of tlie same species vary in color during life, and with some species there is a well marked dimorphism. In some species the dimorpliism is potential, and the future color is settled by some condition
