34 C. H. MoLEOD— MEMO. 



possible in time, iu order to secure conditions which may give rise to a difference in the 

 resulting- longitude. 



The four transit instruments to be used will be precisely similar and each observer 

 will take this instrument as well as his chronograph with him from station to station. 

 The chronographs to be used by the Canadian observers will be alike and are being made 

 by Mr. Saegmuller of Washington. The English chronographs will, I understand, be 

 of the tape form and alike in construction. The electric apparatus to be used at all four 

 stations will be alike and will be a modification of that used iu the French longitiide 

 operations. This apparatus will of course include rheostats and galvanometers for the 

 equilization of the electric currents. A modification of the apparatus referred to, sug- 

 gested by Mr. Carpmael, has met with the approval of the Astronomer Royal and will 

 probably be adopted. 



Note. — The above was, through oversight, omitted from the volume for 1891 and is 

 inserted here as a matter of history. 



