Scientific Intelligence. 239 



We obtain, therefore, Log. 29-830 = 1-47465 

 Log. 29-309 = 1-46700 



(Note — .If we take the more common estimate, 29-82, for 



the mean barometric height, we then have Log. 29-82= -00765 

 1-4750 — Log. 29-309=l-46700 = -00760=75 fathoms or 10000 



450 feet, the exact number given monthly by Mr. Wallace. 



Edit.) ' 76-5 fathoms. 



Hence, it appears that the height of this place, above the sea, is 

 somewhere about 76 fathoms, or 456 feet. This result agrees very- 

 well with what has been given in the monthly report as about the 

 height of the Manse above the sea. As the temperature is supposed to 

 be 32°, no correction, of course, is required on account of temperature. 



5. The observations recorded at 9 o'clock A.M. and 3 o'clock P.M. 

 were taken with a view of being compared with the corresponding 

 results obtained at the apartments of the Royal Society, London, 

 where 9 A.M. and 3 P.M. are the hours of observation. 



6. The number of grains of moisture in a cubic inch of air has 

 been deduced from the following formula given by the author of the 

 article Hygrometry in the Edinburgh Encyclopaedia. 



Let t denote the temperature, B the height of the barometer, L 

 the height of Leslie's hygrometer, and g the number of grains in a 



cubic inch of air under these circumstances; also, let/, denote the 



elastic force of vapour at the temperature t . Then, 



•10953 (/ < - 1 ^i , iL )B 



9 = 447-4 + t ' 



7. In order to obtain a numerical expression of the relative humi- 

 dity of the atmosphere, let 1000 be assumed to denote absolute 

 moisture, and to denote absolute dryness. The numbers denoting 

 the intermediate states of humidity are found by means of the above 

 formula ; for we have only to determine how many thousandth parts 

 the actual quantity of moisture in the atmosphere is of the whole 

 moisture, which it is capable of holding in solution at the given tem- 

 perature. Thus, to determine the relative humidity for the medium 

 state of the atmosphere in the month of May : put in the above for- 

 mula t = 46-3, B = 29-313, and L = 0, the value corresponding to 

 complete saturation ; we obtain g = -00214 grs. But the actual 

 moisture, at the mean height of the hygrometer for May, (namely 

 17-), is -00159 grs. ; and -U0214 : -00159 : : 1000 : 743. There- 

 fore, we have, for the relative humidity of the atmosphere, corre- 

 sponding to the mean height of the thermometer, barometer, and 

 hygrometer in May, the numerical expression 743 ; which simply 

 means, that the actual moisture, corresponding to the medium state 

 of tbc atmosphere in May, is -/,/,;'„ th parts of the whole moisture, 

 which, under these circumstances, it can hold in solution. 



S. I will only remark farther, that the mean point of deposition 

 for the year is 6°-7 below the mean temperature; — a result which 

 also agrees with what was to be expected. 



Without laying any undue stress on the coincidences here pointed 

 out, as indicating accuracy in the observations from which the results 

 have been deduced, I may be allowed to remark, that there has been 

 DO adjusting of numbers for the purpose of bringing out results 

 apparently satisfactory. 



