SCIENTIFIC SUMMAKY. 
443 
the rock is seen to consist of a yellowish-grey compact base, in which 
crystals of clear glassy felspar are imbedded ; they exhibit no striae ; their 
fracture is sharp and splintery. A thin section examined in polarised light 
with crossed prisms exhibits a beautiful group of crystals of felspar and 
nepheline porphyritically imbedded in a fine-grained matrix composed of 
minute crystals of nepheline, felspar, and hornblende ; when cut very thin, 
the hornblende alone exhibits colours, the hexagonal sections of nepheline 
being black, the rectangular white ; the felspar is also either dark or light, 
and the general appearance is that of a mosaic of dark and light stones inter- 
spersed with small brilliant-coloured crystals of hornblende ; the whole 
forming a matrix in which the larger crystals are set. In thicker sections 
the felspar and nepheline display fine colours, but the minute structure is 
not so well seen. 
PHYSICS. 
A New Key for the Morse Printing Telegraph was described to the British 
Association at Edinburgh by Professor Zenger. He said that, at the Norwich 
meeting, he had had the honour to show a new automatical key for the 
Morse printing telegraph, which printed three different signs — viz., a point, 
a short line, and a longer line. That arrangement restricted the telegraphist 
to a certain speed, but he had constructed the key now shown in order t 0 
allow a clever telegraphist to obtain the highest speed attainable. He 
showed a model, and explained it in detail. The rate of velocity was indi- 
cated by a small bell sounding as often as the cylinder revolved. By the 
mechanical arrangement, whatever the speed of the paper and the clock- 
work moving it, the relative length remains unalterably the same. On the 
working instrument, the printing apparatus with its rollers for the paper 
sheet is attached to the key, forming only one apparatus together. By using 
three signs, the combination of 1, 2, and 3 elements gives 39 signs. This 
will do for all letters, figures, and phrases commonly used, and spare nearly 
30 degrees of space, and therefore of time of transmission. In a brief dis- 
cussion, it was said that the adoption of Professor Zenger’s apparatus would 
do away with the mistakes now so often made by the doubting whether the 
short line meant a line or a point. 
The late Professor Payen . — Physics has lost one of its great masters 
through the death of Payen, which occurred a few months since. u Les 
Mondes ” of June 29 contains a short account of his life. In 1824 he was 
the first who pointed out the rational method of applying manures in 
agriculture, and about the same time brought forward the theory of the 
decolouration of liquids by animal charcoal, also suggesting the use of 
the residues of sugar-refining (scums which contain more or less animal 
charcoal along with other substances) in agriculture. In 1830 he laid the 
foundation of the proper valuation of manures, according to their richness in 
nitrogen. The late author’s exhaustive researches on amylaceous matter 
settled the exact structure, mode of formation, and the derivation of dex- 
trine and glucose from starch; the existence of diastase, also, was first 
pointed out by the deceased. Prof. Payen, very well known, also, among a 
