414 F. Dellmann on Atmospheric Electricity. 



measurements were made with a brass arm not perfectly straight, 

 the difference between the angles made with one half when 

 turned round being about half a degree. 



My friend, Prof. Roeber of Berlin, has had the kindness to 

 examine mathematically the theory of the instrument. His 

 memoir will also be found in the second Year's Report of the 

 Royal Meteorological Institution *. From his double formula 

 two new methods of interpolation can be deduced, whose results 

 differ little from each other and from those obtained by Kohl- 

 rausch's method. Nearly three years ago Roeber furnished me 

 with a formula which almost entirely coincides with that since 

 published for the Munich instrument. 



II. Results. 



Schonbein has already drawn attention to the fact that, by 

 means of light and electricity, the oxygen of the atmosphere 

 passes into the condition of ozone ; and the influence of ozone 

 on organic life, particularly its influence on diseases and on the 

 destruction of miasma, has already been frequently recognized. 

 Quetelet noticed the remarkable diminution of atmospheric elec- 

 tricity during the first seven months of the year 1849, and the 

 simultaneous appearance of cholera in Belgium. Something 

 similar occurred in the month of January 1853, and we read 

 of bad fevers, from which Switzerland in particular suffered. 

 The importance of electricity on all organic life being more and 

 more recognized the more we study its nature, atmospheric 

 electricity, as one branch of the same, will also gain more and 

 more interest the more we seek to shed light upon what has 

 hitherto been a dark field. I should not venture to come forward 

 with the results of a single year's observations, were I not con- 

 vinced that their completeness and accuracy give them a value 

 which surpasses that of many other observations extending over 

 many years. I further hope by this publication to persuade 

 others to advance hand in hand with me towards the same goal, 

 either by comparing other phsenomena with those of atmospheric 

 electricity, or by undertaking similar observations, for which 

 purpose I gladly offer my assistance. One great advantage of 

 my whole apparatus, is that it can be employed anywhere. 



Although the absolute magnitudes of atmospheric electricity 

 increase with the height, yet an arrangement can easily be hit 

 upon by means of which the values obtained at different places 

 may be compared one with another. For this it is only neces- 

 sary that in all places the collector be constructed in exactly the 

 same manner, due regard being had to all circumstances, and 

 that with the measuring instrument a constant unit be adopted. 

 * Also in Poggendorff' s Annalen, vol. Ixxxix. p. 283. 



