TT0 
Observatory, by Dr. J. L. E. Dreyer of Armagh; 
Opium, by Mr. E. M. Holmes; Optics, by Lord Ray- 
leigh; Orchids, by Dr. M. T. Masters; and Organ, by 
Prof. R. H. M. Bosanquet. 
— At the meeting of the Royal astronomical so- 
ciety, May 9, Prof. C. Pritchard of Oxford read a 
paper on the proper motions of forty stars in the 
Pleiades, which he has determined from a compari- 
son of Bessel’s heliometer-measures with recent mi- 
crometric measures made at Oxford, and also with the 
positions determined ten years ago by Wolf at the 
Paris observatory. The existence of certain small 
proper motions of these stars in different directions 
is interpreted as indicating the mutual interference 
of a group of gravitating bodies. At the same meet- 
ing of the society, Dr. David Gill, her Majesty’s as- 
tronomer at Cape Town, described the mounting of 
the great thirty-inch refractor now constructing at 
the shops of the Messrs. Repsold, at Hamburg, and 
which is to be set up this year at the Pulkowa ob- 
servatory, near St. Petersburg. The tube of the 
telescope will be about fifty feet long; and the me- 
chanical arrangements of the mounting will be so 
thorough and convenient in use, that a single assist- 
ant, sitting at the lower end of the polar axis, will 
be able to point the instrument accurately to any 
part of the heavens. A paper was likewise read by 
Mr. A. A. Common of Ealing, proposing the appli- 
cation of his method of relieving the friction in the 
axes of large instruments, to the polar axis of a 
large equatorial telescope. In his plan, somewhat 
similar to that of the Repsolds, the centre of flota- 
tion in a bath of mercury is vertically underneath 
the centre of gravity of the polar axis and telescope 
combined. The Repsolds employ, instead, a friction- 
roller under the centre of gravity to support the Pul- 
kowa telescope. 
— Dr. A. Berghaus has called attention in Aus- 
land to the successful revival of the use of fibres 
derived from the nettle, as a material for spinning and 
weaving. That the common stinging nettle was 
formerly largely used in Germany to afford a material 
for the making of woven fabrics, is proved in an 
interesting manner by the fact that the old Ger- 
man name for muslin literally means ‘ nettle-cloth’ 
(nesseltuch). Before the new material was intro- 
duced, the fabric most nearly corresponding to the 
new cloth must, undoubtedly, have been made from 
the nettle, and, as in many other cases,. the name 
remained (at least for a time) after the thing was 
changed. But on the introduction of cotton from 
America, the nettle soon fell into neglect; and it was 
not till comparatively recent years that attention 
Was again called to it. After the exhibition at 
Philadelphia, when the German manufacturers saw 
that they must do something to put themselves on 
an equal footing with rival nations, Professor Reu- 
leaux, their representative in America, strongly ad- 
vised them to pay more heed to the products of their 
Own soil in order to make themselves less dependent 
on foreign supplies, and, among other plants suitable 
for the purpose, he reminded them of the nettle.’ 
An enterprising lady took the matter up practically, 
SCIENCE. 
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[Vou. III, No. 72. 
and, in the end, with the most gratifying success. 
She planted nettles on a part of her estate composed 
of poor stony ground, covered only with a thin layer 
of soil, and, at an agricultural exhibition held in the 
autumn of 1877, she was able to exhibit nettle-fibres 
in all stages of preparation up to yarn. This suc- 
cess convinced the unbelievers; and hundreds there- 
upon began to cultivate nettles, not only in Germany, 
but also in Switzerland, Belgium, Hungary, Poland, 
Sweden, Austria, and even in this country. Two 
years later the first German manufactory devoted to 
the new industry was opened at Dresden. The ex- 
periments made there at. first were not altogether 
satisfactory; but, after repeated attempts, a yarn was 
produced which left nothing to be desired. In this 
manufactory the common nettle is used to some ex- 
tent, but the best results are obtained by using the 
Chinese nettle, which yields a fine glossy yarn, of 
greater strength than the common nettle. The fibre 
is hence knownas China grass. 
— In the first number of the Jahrbuch der Deutsch- 
en malakozoologischen gesellschaft for 1884, Heyne- 
mann continues his studies of little-known genera of 
slugs. From an examination of the type-specimen, 
he shows that Aspidoporus of Fitzinger is founded. 
on a malformed individual of Amalia carinata. The 
genera Urocyclus, Elisa, and Dendrolimax are also 
discussed. Brusina, in a paper on the Neritodon- 
tas of Dalmatia, indulges in a lively polemic with 
relation to some rather peculiar publications by 
Bourgnignat. Both papers are illustrated. In the 
accompanying Nachrichtsblatt, Simroth discusses the 
European and especially the German slugs, a group 
of the Pulmonates which has recently excited much 
interest. Simon and Boettger describe the land-shells 
of the Cottish Alps, and Kobelt describes some new 
operculated land-shells from the Philippine Islands. 
— At the séances held during April by the Société 
frangaise de physique, in the rooms of the observatory, 
the curious experiment of using a gloved hand as a 
telephone-receiver was exhibited. Fig. 1 shows the 
apparatus used, P and M being a battery and a micro- 
phone-transmitter in the main circuit; B, an induc- 
tion-coil with the break-circuit closed; while P’ is a 
battery, and R, ordinary holders for receiving a shock. 
Mehiget, Il. 
When two people, each with a gloved hand, take hold 
of the two holders with their bare hands, and one of 
them holds his gloved hand over the ear of the other, 
any conversation or music near the microphone be- 
comes audible to this other; or, if they hold one an- 
other’s ears, both may hear. By leaning their heads ~ 
together, so that their ears would touch except for a — 
sheet of paper placed between them, the same result 
was obtained. It was also found possible to do away 
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