356 REPORT— 1851. 



thermometers attached to the stand, " The index corrections have been 

 applied. The minimum temperature was generally read at 10'' a.m. and the 

 maximum at sunset." 



In O are contained the corrected readings of the dry standard thermome- 

 ter by Newman, until September 22 (23''), and of Ronchetti's dry after that 

 date ; both affixed to the stand. 



In P are contained the corrected readings of the small wet-bulb thermo- 

 meter by Newman, which belonged to the Mason's hygrometer, until Sep- 

 tember 22 (23''), and of Ronchetti's wet-bulb after that date. 



In Q the differences between the readings of the dry and wet thermometers 

 are stated. 



In R is contained the observed dew-point by the old Daniel hygrometer 

 until February 1, 1851. The little break in the mercurial column of the 

 immersed thermometer of this instrument occasioned probably " no appre- 

 ciable error in the observations, as a strict watch was kept on the constancy 

 of the break." After February 1 the dew-point was observed by the new 

 instrument. " The observations of dew-point, as entered in the Journal, 

 have not been corrected for index error." 



S has been scarcely used. 



In T are contained some occasional readings of the Saussure 8-haired 

 hygrometer, not corrected for the error of its scale. 



In U and V are contained the resultsof observations of the rain- and vapour- 

 gauge. The mode of using it was as formerly. " The reading was noted 

 and the index set to zero at sunset. When the reading showed that the 

 evaporation had been greater than the precipitation, the result was noted in 

 column U ; and when the reverse was the case, the entry was made in co- 

 lumn V." 



In W is contained the amount in cubic inch measure of precipitation be- 

 tween sunset and sunset, as ascertained by means of the old Rain-gauge 

 and measure. 



In X the direction of the wind is noted, as shown by the Vane on the 

 Dome. 



In Y the static pressure of wind is noted from observations of the Balance 

 (standard) anemometer, used as formerly*. 



In the space (?. e. a page) headed General Remarks, ^c, the figures 

 adjoining the margin denote the estimated " Extent of cloudy sky, a clear 

 sky being considered 0, and a complete covering of clouds 10." 



" The general remarks and occasional observations include the kinds of 

 clouds prevalent, general remarks on the weather and meteorological phae- 

 nomena, and notes on the electrical observations." 



They comprise, in addition, notices when the Lamp, in the Volta's lantern, 

 at the head of the conductor was known to be not burning, or burning low. 



Both that lamp and the lamp which warms the glass support of the con- 

 ductor, &c., were constantly burning, wiih the above-mentioned rare excep- 

 tions. They were trimmed three or four times per diem. 



A few other matters relative to the management, &c. of the apparatus, &c. 

 are stated in this space. 



Olive-oil was burnt in the lamps. 



The average number of either compoundfor single daily electrical obser- 



* The Barometers, Thermometers, Hygrometers, &c., have been alluded to at pp. 341, 342 

 and 343, ante. 

 t A compound observation is understood to comprehend the notes of tension recorded on 



