hair near the weight, and is pivoted the water evaporates fast, and the on a pin very near that end. A slight wet bulb thermometer stands much movement of the end fastened to the lower than the other, while on hair, will thus cause Hair Hygroscope. a greater one in the one a little more This kind of hygroscope can be made also of twisted cat-gut, which untwists by absorbing moisture. The little houses with figures of a man and woman, one of whom appears in moist and the other in dry weather, are made in this way. Wet and Dry Bulb Thermometers. damp days the water does not evaporate so quickly, and so it stands only a little lower. Hence the instrument is used to tell whether the air is dry or damp. Phial Barometer. This is really a kind of hygroscope, because it does not measure the pressure of the air, but shows only whether it is dry or moist. Cut off about half of the neck of a common glass phial (see CHEMICAL EXPERIMENTS, directions for glass-working) and nearly fill it with water, which may be colored if desired. Place the finger Wet and Dry Bulb Thermometer. over the mouth of the phial and inThis form of hygroscope consists of vert it; the water will not run out two thermometers hung side by side. even when the finger is removed. Around the bulb of one is tied a Suspend the phial, neck downward, piece of soft cloth, the end of which by a string. In dry weather the undips into a cup of water. The cloth der surface of the water is either soaks up the water, and keeps the level or concave, but in damp bulb continually wet. The evapora- weather a drop appears at the mouth tion of the water on the bulb keeps of the phial, and keeps enlarging it cooler than the other, so it always till it falls. This is caused by the stands lower. On very dry days deposition of moisture from the air. is so slight, that it will sail along A C The runners, three in number, are the friction of the runners on the ice at the ends of the cross-bean (called the "runner plank") and at the rear of that running lengthwise (called "centre timber"). On the forward end of the centre timber is bolted the bowsprit. The rear runner serves as a rudder. The forward runners are fastened by a bolt on which they can rock forward and backward. There is one mast, which is placed slightly in advance of the cross-plank. An oval box, holding two persons, is fastened just above the rudder; except for this the boat is merely a frame. The largest ice-boats are 50 to 60 feet long, and 25 or 26 feet wide. They are rigged as sloops, cat-boats (see Fig. 3), or with a lateen sail (see SAILING). Ice-boats may sail faster than the wind, as shown by Fig. 4: Snow Flake" is said to have made the same distance in seven minutes, and in 1882 the "Haze" did the same, making at one time two miles in one minute. Many similar instances of great speed are related, but it is hard to get an official record, for ice-boats go fastest when least expected, and the time made in regular races, as shown below, is far slower than that just given, though still very great. Suppose the wind to be blowing in the direction of the arrow at the The sails of the boat are set nearrate of twenty miles an hour; then, if ly fore and aft, and the boat is manA B is a mile, the boat cannot sail aged almost entirely by the rudder, that distance directly before the the speed being so great that the wind in less than three minutes; but | helmsman has no opportunity to Fig. 2. brought into the wind and the crew disembark to reef it. The boat is stopped usually by bringing her with Fig. 3. her head to the wind, and then slackening the sheet. Many iceboats have a brake which can be as to "spill" (or lose) the wind and then run over the crack so that both forward runners cross it at the same time; and some disembark and help the boat over. Others would simply slack both sheets and let the boat's momentum carry her over. The wind often forces the boat over so that the weather-runner is lifted clear of the ice, leaving only the leerunner and the rudder. The boat is then said to “rear," and must be eased by bringing her into the wind, if the boat is beating to windward. One or two men often stand on the windward runner, to keep it down. The greatest speed, running free, is made by steering across the wind till a maximum velocity is reached, and then steering down the wind without slacking the sheet. The momentum will carry the boat faster than the wind for some distance, when she must again be brought up and headway regained. The yachtsman often wears coverings of wire gauze over his eyes and mouth to keep out flying snow. The strain on the timbers of an ice-yacht makes it necessary that they shall be perfect in grain and well seasoned. The runners are made of iron or steel. Ice-boats on the Hudson. wear at first, but by use acquire Iron runners boats have two sets of runners, sharp ones for smooth ice and strong winds, and duller ones for rough or soft ice. Crossing a Crack. what is called a "water polish," the surface becoming very hard. Many A Tom Thumb ice-boat holds only one person, and can be made by nailing boards together as in the diagram. The runners are made of skates. The rear one, or rudder, is screwed to the end of a stout wooden upright which passes through a hole at the rear of the main plank. To this upright a horizontal handle is fastened, forming the tiller. The steersman sits just forward of the tiller with his feet on the crossplank. The rudder may be omitted, the rear skate being fixed, like the others; but in this case the steersman must have on skates and steer with his feet. Any simple sail may be used. The chief ice boat clubs in the United States are on the Hudson River and the Shrewsbury River in New Jersey. A silk challenge pen any organized club in this country or Europe. A list of winners of the pennant, with their times, is given in the appendix. The following are the chief sailing rules of the Hudson River Ice Yacht Club: RULE I. The following sailing rules and regulations shall govern and control all the regattas and all the races of this Club, and all contests sailed under its auspices, unless otherwise specified between parties making a match. or yachts in arrears to this Club, cannot be entered for any race. RULE V.-Touching Buoys, etc. An ice-yacht touching any mark, boat, or buoy, used to mark out the course, shall forfeit all claim to the prize, except as in cases specified in Rules VII, IX, X. RULE VI.-Rule of the Road. When two yachts have to cross each other on the opposite tacks, the one on the starboard must invariably keep her course, and the one on the port tack must keep away and pass to leeward, or tack short, when the smallest doubt exists as to her being able to weather the other. All expenses of damages incurred by yachts on opposite tacks running on board each other, fall upon the one on the port tack, unless the one on the starboard tack has kept away with the intention of passing to leeward, in which case the expense of damage falls upon the yacht on the starboard tack, because, by her keeping away, she may have prevented the other passing to leeward. Should a vessel on the port tack attempt to weather one on the starboard tack when it does not seem possible to do so, the latter, rather than keep away, should put her helm down. Nothing should induce a vessel on the starboard tack to keep away. RULE VII.-Courses. Any iceRULE II. Classification. Yachts yacht purposely bearing away or shall be divided by sail area into altering her course to leeward, and four classes as follows: First class, thereby compelling another icemeasuring 600 square feet of sail yacht to bear away to avoid a colarea and over; Second class, meas-lision, shall forfeit all claim to the uring 450 and under 600 square prize, and pay all damages that may feet; Third class, measuring 300 ensue-unless, when two ice yachts square feet and under 450; Fourth class, measuring less than 300. RULE III. Objections. If any objection be made with regard to the starting of any ice-yacht in a race, such objection must be made in writing to the Regatta Committee at least one hour before a regatta. RULE IV.-Entry of the Yachts. Unmeasured or unrecorded yachts, are approaching the windward shore, a buoy or stake boat, together with a free wind, and so close together that the weathermost cannot bear away clear of the leewardmost, and by standing further on would be in danger of running on shore, or touching a buoy or stake boat; then such leeward most ice-yacht, on being requested to bear away, is imme |