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September, 1909 a steel base plate with bronze washer be- tween. All hoisting and _-- swinging sheaves are of cast steel, brass bushed, with pins of ample size to prevent un- The dipper handle is of armored, due wear. wood, steel The dipper is of 114 cu. yd. capacity, square, with four tool steel teeth, cast steel back, cast steel lip, lugs, and forged bail, braces and hinges. The boiler is of the locomotive type, 66 in, diameter by 14. ft. long, covered with magnesia boiler covering, and is supp ied with water by means of in- jector and steam feed pump. Oil is supplied to all engines by means of a Hills-McCanna force feed lubricat- ing pump, insuring constant and suff- femme supply of oi] at all times, All sheaves, bearings, etc., are fitted with dope cups of ample size. Each engine is also furnished with a hand oil pump and the ram and the pump are furnished with a lubricator. It will be seen from the above de- scription that the machinery is 'arge enough to carry a 2% cu. yd. dipper for ordinary work, but inasmuch as the material at present being excavated is rock, the smaller dipper was sub- stituted. The smaller dipper also bet- ter fits the present work, THE PORHYDROMETER. An instrument to which the above name has been given has been attract- ing more or less widespread attention in Great Britain recently, and is thus described : This invention is an instrument for weighing the dead weight placed on board or removed from any ship, barge or other floating vessel to which it is fitted. The instrument is based upon the principle that a body floating in a liquid of whatever density displaces a quantity of that liquid exactly equal to its own weight, and by its application the vessel is transformed into a weigh- bridge or weighing machine. In _ the center of the vessel a vertical tube is fitted extending from well below the light draught water line to well above the load line, and connected by a pipe with the outside shell of the vessel, so that when the valve or cock is opened the water in which the vessel is floating has free access to the vertical tube and rises in it to exactly the same level as outside the vessel, the water or liquid, both in the tube and outside the vessel, being thus of the same density. Inside the vertical tube is fixed a vertical float called the 'aero- meter, which, having exactly propor- tionate horizontal areas at the various immersions to the areas of the planes of flotation at the present draughts or im- mersions of the vessel, has an exactly similar displacement and reduces the €normous weights dealt with to ameas- urable quantity. The aerometer being immersed in the same liquid to the Same extent as the vessel itself by its TAE MARINE REVIEW consequent exact y proportionate dis- placement loses an amount of weight exactly equal to its displacement. This loss of weight disturbs the balance of levers and is exactly registered or counter balanced by moving the weights along the steelyard, giving a correct reading of the weights placed on board the vessel, and vice versa weights re- moved. The tube being fixed in the center of the vessel neither transverse inclination nor change of trim will at- fect the accuracy. To the ship owner, charterer and Fen Ae 47. 46 45 ee 43 42 "1 40 SECTION THRU WINGS LOOK ING OUTBOARD 319 cargoes in one operation, or parcels of goods loaded or discharged by them- selves, when they are comp'etely placed on board, or taken from the vessel, a great saving in cost is effected; the density of the water does not affect the accuracy of the instrument. The por- hydrometer can be fitted to any vessel of any type, whether large or small, or for the sea, river or lake service. The Italian government has decreed that the customs shall accept as correct the weight of cargoes measured by the porhydrometer,. This: means that: i- 39 368 37 floating Loch te Oregon Ory Lock Co. Section THroucH Wuncs_ LOooKING Portland, are OutBoarp Froatinc Dock oF Orercon Dry Deck Co. shippers, the advantages of this in- strument are summed up as fol.ows -- the cargo is accurately weighed in one operation; the captain or officials in charge are at all times in a position to ascertain the weights on board; coal taken at a coaling port can be weighed correctly; in case of leakage through collision, grounding or any other cause, the element of danger, and capacity of the pumps to cope with it, can be ac- curatey gaged and the course regu lated accordingly; by weighing total stead of a ship-owner. paying 23 cent- imes per ton for the customs' weighing dues he has only to pay 8 centimes, saving nearly 200 per cent in Italian ports. In the case of leakage, the por- hydrometer has attached to it an elec- tric bell, so that when a leak is sprung a warning is given by the ringing of the bel'. This done, the captain of a ship can calculate what port he can make and whether or not to abandon his ship. : So far as application to ships for