( 142 ) 
[February, 
notes. 
Mr. D. Win Stanley has described to the Manchester Literary 
and Philosophical Society a new instrument for recording sun- 
shine. A differential thermometer with a long horizontal stem 
in which latter is contained throughout the greater portion of its 
length some fluid intended to operate by its weight— is attached 
to a scale beam or some equivalent device which also carries a 
lead pencil by means of which the record is made. The whole 
s so arranged that in its normal state it rests gently— upon that 
side to whfch the pencil is not attached-on an embankment 
nrovided for that end. Close beneath the pencil point a disc of 
metal rotated at the proper speed carries a paper dial whereon 
marks and figures are engraved corresponding with the hours at 
which the sun may shine. When using this instrument t is 
enclosed within a box which permits one bulb only of T the ther- 
mnmeter that most distant from the clock — to be attested Dy 
Sie radiance of the sun, which when it shines expands the air 
contained therein, forces the fluid along the tube, and by altering 
the equilibrium of the beam brings some portion of its weight to 
bear upon the pencil point, and so the record is commenced 
When^the sun becomes obscured, the air expanded by Ms rays 
contraas the fluid in the tube returns, the normal equilibrium is 
restored and the pencil ceases to produce its mark. The stem 
of the thermometer is 18 inches long and about the eighth of an 
inch in bore. Mercury, in consideration of its weight, is the 
fluid Mr. Winstanley employs, and in conjunaion with A some 
sulDhuric acid is enclosed, because of the mobility which is 
thereby gained. The bulbs of the thermometer are 2 inches in 
diametef or thereabouts, and that they may be more rapidly 
affeaed the glass thereof is thin. Both are blacked, and the 
one intended S to receive the radiance of the sun projeas above 
the box in which the apparatus is contained into a dome of 
8 At a subsequent meeting Capt. Abney, R.E., F.R.S., ^bffed 
his photographs of the ultra-red portions of the solar spearum, 
andfirst 8 of all showed that the light transmitted by ordinary 
bromide of silver was of an orange tint, showing absorption in 
the lowest end of the spearum. He then explained how he had 
tried to load the molecules comprising this bromide of silver by 
means of gum resins, and that he had thus been enabled to 
SfntograDh slightly beyond the lowest limit of the visible 
spearum. Further researches proved that bromide of silver 
could be prepared in two molecular states— one that already 
