198 



"\V. MARRIOTT— nEDUCTION OF 



half-inch botween 27'5 ins. and 31"0ins., it Avill bo necessary in 

 the latter case to interpolate for intermediate readings. Suppose 

 the corrections to be 



'Zi-o 

 — 010 



ms. ins. 



28-0 28-5 

 —•009 —-008 



ms. 

 29-0 

 —•007 



ms. 

 29-0 

 —•006 



they should be interpolated as follows : — 



•010 



IDS. 



27 •To 



to 

 28-2o 



29^75 

 •006 to 

 30-2O 



—•009 



—•005 



ins. 

 28-2.5 



to 

 28^75 



30^2o 



to 

 30 •To 



ins. 

 30^0 

 —•005 



—•004 



ins. ins. 



30^5 31-0 

 —•004 —•003 



ins. 

 28^75 

 •008 to 

 29-25 



30^75 



to 



3roo 



•007 



-•003 



Table I. — Corrections for Reducing Olservations of the 

 Barometer to 32°. 



