90 
SHORT NOTES ON PROFESSIONAL SUBJECTS. 
On account of the rigidity of the red square, no wind can blow it end on; nor 
dare any man fire a shot until the pole at his elbow is pulled down by the marker 
at the butt to show that he is ready. When we remember the numerous accidents 
that have occurred under the rude system of signalling, now in use, this total 
immunity from danger which the marker enjoys is the most important result of 
Captain Lysons’ invention, and has struck every one, whether regular or volunteer, 
who has seen it at work. No excuse can be given now for not seeing the marker’s 
danger flag, as it is in the midst of the firing party themselves, whether they are 
firing at 400 or 900 yards. 
And to prove how accurately the poles are balanced, and yet with what ease they 
can be pulled down owing to the leverage given, which is presently to be described, 
the writer of this paper can state that at a distance of 800 yards, with the cord 
passing over a ploughed field, unsupported by rings or poles, he pulled the pole 
into a horizontal position with one hand; and that his letting go the running end, 
and the consequent springing of the pole into a vertical position were almost 
instantaneous. 
It sometimes happens, more especially upon country ranges and among volunteers, 
that the firing is continued until it is so dark as to render a red flag, even at right 
angles to the range, not very distinguishable. To obviate a difficulty caused by a 
practice which is much to be deprecated, Captain Lysons has arranged to have a 
lamp with a powerful reflector hung above the red square, whose white light is 
visible at a great distance when the pole is erect, and yet by an ingenious arrange¬ 
ment is invisible when the pole is in a horizontal position. 
65. Description of a method of taking heavy weights over broad 
AND DEEP DITCHES.* 
The undermentioned plan was adopted in May and June last for taking 
guns, carriages, and platforms across the ditch surrounding the Drop Eedoubt at 
Dover, under the superintendance of this officer. 
The guns (40-prs. of 32 cwt.) were taken from the redoubt across the ditch. 
From crest of exterior slope to edge of glacis 87 feet (this was the distance the 
weights travelled in the air). 
The heaviest weight taken over (consisting of two dwarf traversing platforms 
lashed together) was about 67 cwt. 
Sheers (. A ), length of each spar 86 feet. Gyn, common, 18 feet, used as 
sheers (A), three guys and capstan (£), were placed as shown in plan and 
elevation. (See also large sketch). 
The triple blocks of two gyn tackles were connected with the heads of the gyn 
and sheers respectively. The running ends of the falls of both tackles were led 
by leading blocks ( x ) and ( y ) to the capstan, when both were coiled on the drum 
in such a way that when one was hauled in the other was paid out. (See Fig. 1). 
* By Lieut. G. Maekinlay, R.A. 
