10 



REPORT — 1851. 



Tables of the Deviations of the Compasses of H.M. Steam Ships Ajax, of 58 guns, and 

 Blenheivi, of 58 guns, under the two conditions of their funnels, viz. Up and Down. 

 Observers, Capt. Johnson, Commander Strange, and Mr. Thompson. 

 These ships have engines of 450 horse power, and are propelled by the screw. 

 They have what are termed teloscopic funnels, capable of being lowered when re- 

 quired ; the Ajax having two funnels abreast, the Blenheim one funnel. 



Ft. in. 

 Heigbt of standard compass above 



thedeck 5-8 



Distance from funnels 27 



Height of funnel when up 23 6 



Height of funnel when down 4 6 



Depth of funnel below deck when 



down 19 



Diameter of each funnel 4 



Thickness of the iron funnels 0-^ 



Ft. in. 

 Height of standard compass above 



thedeck 5 3^ 



Distance from funnel 22 



Height of funnel when up 24 



Height of funnel when down 8 



Depth of funnel below deck when 



dov.n 16 



Diameter of funnel 6 



Thickness of iron funnel Oj^g 



Thickness of steam chest 0y% 



E. J. Johnson, 



Capt. R.N., Superintendent of the 



Compass Department. 



