to create a seal between the periscope 10 and the glass to help prevent dirt from accumulating within the periscope 10 the periscope 10 is preferably mounted to the cab 11 of the tractor 12 by use of a horizontal brace 36 which can be bolted to the cab 11 the brace 36 is secured to the periscope 10 by a strap 38 which is wrapped around the periscope 10 and bolted to the brace 36 in addition a cab hook 40 secured to the periscope 10 and is adapted to hook over a portion of the cab 11 helping to secure the periscope 10 to the tractor 12 the periscope 10 may optionally include a spotlight 42 mounted to the hood 32 of the periscope 10 the light 42 is used to illuminate the inside of the wagon 18 if the periscope 10 is used at night the convex mirror 30 may optionally be adjustable by the user to adjust the field of view through the periscope 10 fig5 is an enlarged partial sectional view of the convex mirror 30 and the top portion of the hood 32 the mirror 30 is shown mounted to the hood 32 by a ball joint comprised of ball 44 and sleeve 46 the ball 44 is movable within the sleeve 46 such that the mirror 30 can be tilted in any direction desired when the periscope 10 is mounted to the side window of the cab 11 of the tractor 12.