LYDD EXPERIMENTS, 1890 . 
39 
laying for line, while the automatic correction of deflection for differ¬ 
ence of level of wheels is not so necessary with siege as with field 
guns, since with the former, which fire from a platform, this correction 
is practically constant so long as the direction of fire remains unaltered. 
Under these circumstances it appears that French's sights, with a 
good clinometer, are much simpler in use than Scott's sight and give 
at least equally accurate results. 
It will, therefore, be advisable to use French's sights and the clino¬ 
meter exclusively for all R.M.L. howitzers; since, however, these 
sights cannot be conveniently employed with B.L. howitzers, on 
account of the shape of the piece, it will probably be necessary to 
improve the Scott's sight in the direction suggested above. 
Series (N .)—To test the value of theodolite observation of fire by 
night. . 
In this series 10 rounds were fired by night on four occasions, under 
different atmospheric conditions varying from bright moonlight to a 
dark and stormy sky. The average error of the whole series was 
seven yards in range and 5*5 feet in line, which is about the same as 
would be the case by day. 
As might be expected, the errors tend to increase in bad weather or 
exceptional darkness. 
So far as this experiment goes, the results are very satisfactory ; 
since they tend to show that theodolite observation is as trustworthy 
by night as by day. The Committee, however, consider that the 
experience at present obtained is not sufficient to enable them to form 
a decided opinion on this point, and they, therefore, propose to carry 
out further trials in this direction. 
Amongst other experiments the service platform laid horizontal was 
tried and gave good results. 
This system would be advantageous in the case of R.M.L. guns and 
howitzers, of which the recoil is useful as affording facility for loading, 
pieces are easier to lay upon them than on sloping platforms, and they 
do not necessitate any allowance for difference of level of wheels when 
the line of fire is not normal to the crest of the parapet. For B.L. 
guns and howitzers they are not desirable, since it is advantageous that 
these shall run up after firing, while the tendency to lift the front of 
the platform, due to the position of the pivot (which is more marked 
with B.L. than with R.M.L. guns, etc.), may in time result in a reverse 
slope of the platform which would be very objectionable. 
It would, therefore, appear to be desirable that platforms for R.M.L. 
guns should be laid horizontal, and those for B.L. guns with a slope to 
the front. 
The general behaviour of the service platform, when laid on earth, 
was so satisfactory that the only desirable modification would appear to 
be in the direction of some arrangement for holding down the front 
when used with high velocity guns. 
The experimental guns and howitzers used in 1890 were - 
1. The 6-in. B.L. 3*5 ton wire gun. 
The shooting of this gun was very satisfactory, but the combination 
