Dictionary of Tools and Implements 



the grasp and the inclination of the wrist, 

 which is soon acquired by a Uttle practice. 

 In this way very hard woods may be dressed 

 for any purpose, with a degree of ease and 

 accuracy not attainable with the small axe 

 used in this country. In order to grind the 

 common Adze the handle must be removed, 

 and this is easily done, as the eye of the tool 

 is larger externally than internally, as in 

 the common pickaxe, so that the tool can- 

 not fly off when in use, but a blow on the 

 end of the handle easily removes it. — Sec 

 Axe. 



ANEMOMETER (From the Greek ajiemos, 

 the wind, and vietron, a measure). — An 

 instrument for determining the force of the 

 ^vind. A knowledge of the various pheno- 

 mena which accompany changes in the atmo- 

 sphere, and of the law by which they are 

 regulated, are of the greatest importance to 

 persons connected with the cultivation of the 



Fig. 2. — Liiid's Anemometer. 



soil. As the instruments required to record 

 observations are few and inexpensive it is very 

 desirable that all farmers and gardeners 

 should be provided with a set. They com- 

 prise an anemometer, or wind guage, a baro- 

 meter, thermometer, electrometer, hygi'ometer, 

 and rain-guage — all of which will be found 

 described, under their several heads. Lind's 



VOL. I. 



273 



anemometer (fig. 2), though not a perfect in- 

 strument, is the cheapest and only one within 

 the reach of ordinary observers, and is useful 

 for comparative results. It consists of two 

 glass tubes, about nine inches long and four- 

 tenths of an inch in diameter, connected at 

 ■ their lower extremities by another tube of 

 glass only one-tenth of an inch in diameter. 

 The object of the small tube, which connects 

 the two larger ones, is to prevent the oscila- 

 tion of the fluid by irregular blasts of wind. 

 To the upper extremity of one tube is fitted a 

 thin metal cap bent at right angles, so that its 

 mouth, d, may receive the current of air in a 

 horizontal direction. Water is poured in at 

 the mouth till the tubes are nearly half full, 

 and a scale of inches and parts of an inch is 

 placed between the tubes. The whole turns 

 freely on an axis or pivot /, and on the top a 

 small vane is attached (not she^vn in the en- 

 graving), so that the mouth may always be 

 towards the quarter from which the wind 

 blows. When the wind blows in at the mouth 

 of the cap, the column of water is depressed 

 in the tube below the cap, and elevated to a 

 similar extent in the other tube, so that the 

 distance between the surfaces of the fluid in 

 each tube is the length of a column of water, 

 the weight of which is equal to the force of 

 the wind upon equal to the base of the 

 column of fluid. The absolute velocity of 

 the wind is deduced from the height of the 

 column of water, or it may be ascertained 

 from the tables constructed for the purpose. 

 When the column of water is one inch high, 

 the force of the wind on a square foot is 

 nearly ^% lb., its velocity 321^ miles an 

 hour, and its character a high wind. When 

 the column marks three inches, the force is 

 upwards of 15^ lb. on the square foot, the 

 the velocity above 56^^ miles per hour, and 

 the character a storm. At nine inches the 

 force on the square foot is stated to be 64 

 lb. 14 oz. ; the velocity 97X miles an hour, 

 producing a most violent huiTicane. Thus, 

 it Avill be observed that in the greatest storms, 

 the difference between the atmospheric pres- 

 sures on the windward and leeward sides of 

 any object does not amount to one-fiftieth of 

 the pressure of the leeward side : for that is 



