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ANNIVERSARY ADDRESS. 15 
The compositor has also a set of sea symbols, wind arrows, 
words, &c., to express any information that is to be given on the 
map ; these are simply glued on to the block wherever they may 
be required, and as they are only 3-inch high, they just come to 
the height of the type. If any curves are required on the map, 
they are bent by hand from strips of soft metal rolled }-inch 
high, and are glued on to the surface in the same way as the 
other symbols. As soon as this is done it is ready to print from 
in an ordinary press,*and a few copies are printed off for distri- 
bution. The map is then sent to the Herald Office, and there 
stereotyped for the morning’s paper, after which it is returned 
to the Observatory for next day’s map. In this way it is thought 
that the information reaches the public sooner than it could by 
any other method. There is, however, nothing to stop the issue of 
copies each day soon after noon if thought desirable ; for it is 
evident that the time required to prepare this map is less than 
others referred to, and printing from type can be done much 
quicker than from a lithograph stone. 
Turning now. to other matters: it will be remembered that 
experiments on the amount of sunshine were made in London, 
by placing a globe of clear glass in a hemispherical cup of wood, 
‘and estimating the amount from the wood carbonized. The 
method was, it is true, éxceedingly rough, but .it yielded an 
interesting result ; unfortunately itturned out that no satisfactory 
estimate of the amount of energy could be obtained. Dr. 
Roscoe invented a small machine to get over the difficulty, by 
exposing, at regular intervals during the day, small pieces of 
sensitive paper, with the object of calculating the sun’s heating 
power from the amount of silver decomposed, but it has not 
been found to give the information required, that is, a continuous 
record of the sunshine. Mr. Seott, Director of the Meteoro- 
logical Office, London, has now designed a modification of the 
original instrument. Instead of wood to be burnt he uses slips 
of cardboard ruled into hours ; these are placed daily at the back 
of the. glass bulb, and cach es therefore has its own record. 
This is a great improvement, but we are not told how the effect 
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