52 POOLE — ox llETEOKOLOGY. 



The instnunents used are a barometer Avith fixed ivory 

 pointer iu a glass cup, to which the surface of the mercury is 

 adjusted, made by Green, of New York, Instrnnient maker for 

 the Smithsonian Institute. Mercurial theniiometer.s to show^ 

 the day's temperature in Fahrenheit, and two thermometert* 

 graduated in centigrade degrees for showing the relative 

 humidity and force of vapour, also made by Green. A 

 horizontal spirit thermometer made by Negretti, registers the 

 extreme temperature at night ; these thermometers are placed 

 on the outside of the house with a N. E. aspect, <> feet above 

 the ground, and about throe inches distant from the wall. The 

 directions of the wind are true north, &c., and not magnetic^ 

 (the variation of the needle being X. 2r><^ ^y. :it the present 

 time). The velocity of the wind is i-e^'oided by (;iie of ISegretti 

 and Lambra's Cup Anemometers, calculating lOOO rcvohitionsc 

 to equal a mile. The greatest velocity observed wa» on the 

 13th December, 34740 revolutions for 12 hours, equal t<7 58 miles 

 an hour, and the calmest night was 24th November, when there 

 were only 277 revolutions in 15 hours, equal to 3 6-10 miles aw 

 hour. The force of the wind is also shown by a board one foot 

 square, made to face the wind, and acting against a spring 

 Salter's balaitce. It therefore show^s the extreme force of any 

 squall; but as there is a good deal of friction the machine is not 

 acted upon by ver^^ light winds. On the 17th January, duiing: 

 the night it marked 44 lbs., l)eing the extreme limit marked od 

 the machine. On the 3rd August a gale from the Avest marked 

 40 lbs. pressure on the square foot, and equalled a velocity for 

 € hours of 53 miles an hour. 



The rain is measured by a square zinc l)ox placed on the 

 ground, with a funnelled mouth ten inches above the ground. 

 The snow is collected in a zinc pail three feet deep, hung like a 

 shi^D's compass, at live feet from the ground, so that drifted 

 snow does not blow in ; and when melted is included m the total 

 quantity of rain recorded to have fallen in each month. 



A meteorological register was ke])t at the All)ion ]\liues for 

 eleven years ; and though only one year has been kept at present 

 at the Caledonia Mine, I have thought it would be interesting to 

 compare them together. 



