4 REPORTS ON THE STATE OF SCIENCE.—1917. 
I. Instrumental. 
The time signals at Shide have been received regularly, with some 
interruptions chiefly due to bad weather, and consequent derangement 
of the instrument. 
The transit lent by the Royal Astronomical Society has been used in 
scpplement ; but it is found difficult to secure the instrument in a per- 
manent azimuth. The method used has been to fix the feet to the pier 
with plaster-of-Paris; and this holds for a time, and then seems to give 
way for some unknown reason. On the first occasion it was naturally 
assumed that there had been some accidental blow to the instrument, 
but it is difficult to believe that this can have happened on all the occasions 
noted. 
The following note has been received from the Astronomer Royal 
for Scotland :— 
An Improved Method of Registration for Milne Seismographs. 
An attempt was made to improve the trace of the Milne Seismograph 
at Edinburgh by using a very small source of light. Though some improve- 
ment was obtained, a limit was soon reached in the diffraction pattern 
resulting from the crossed slits. The following arrangement was then 
adopted. The boom ends in a plate of blackened alumimium foil, in the 
centre of which is a hole rather less than 1mm. diameter. Over this hole 
is mounted a small lens, which forms an image on the bromide paper of 
a specially small source of light. The lens used is achromatic, of 9 mm. 
focal length. The fixed slit-plate was at first left undisturbed; but 
subsequently the slit was widened to about 1 mm. To obtain a sufficiently 
small source of light, a four-candle-power electric lamp with coiled-up 
filament is fixed 30cm. above the end of the boom, and 10cm. below this 
is placed a telescope ocular of 1 cm. focus. 
The results show a striking improvement on the previous records. 
The trace is a line well under =}; mm. thick, and can be magnified ten or 
twenty times with advantage. In this way the short-period oscillations 
of the boom, which formerly resulted in a blurring of the trace, are clearly 
resolved. ‘To obtain the full benefit of the magnification it would be an 
improvement to run the paper at a much slower rate than at present (say, 
at 10) mm. per hour instead of 240 mm.). 
Milne-Shaw Seismographs. 
It was submitted in the last Report that the most important work of the 
Committee for the present lies in replacing the Milne machines (either by 
Galitzin machines or) by Milne-Shaw machines. The difficulties of 
obtaining Galitzin machines have not decreased ; but it is gratifying to 
report that a number of orders have been received for M.-S. machines, 
and that a generous subsidy of 2001. has been made from a private source. 
Hence Mr. Shaw has been working early and late to make a number of 
machines. It is perhaps better to reserve the list for the end of the war, 
but it may be stated that two have been safely delivered to America, and 
others are nearing completion. There have been considerable difficulties 
in obtaining some of the materials, but Mr. Shaw’s patience and ingenuity 
