the Magnetic Compass in Aeroplanes. 



471 



this is adjusted to be equal and opposite to V sin 0, it will 

 be so for all angles of tilt. It is suggested that this rotation 

 of the pair of magnets might be produced by attachment 

 with the steering-gear or with a stabilizer. 



Fig. 7. 





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»U 



Fig. 8. 



<5> 



*l M 



\x^T°y — ^ 



As there are certain mechanical difficulties in the way of 

 this, it may be preferable to produce the correcting field by 

 raising one magnet and lowering the other, the magnets 

 being connected together by a cord passing over pulleys (fig. 8) . 



In order to ascertain whether this correction (fig. 7) is 

 suitable for all angles of: tilt, the field in the plane of the card 



Fig. a 



for a travel of 12 cm. on either side of the zero position for a 

 pair of: magnets 20 cm. long at a distance of 23 cm., one on 

 either side of the compass, is drawn (fig. 9). A sine curve is 



