Jan. 27, 1888.] 



SCIENTIFIC NE^A^S. 



91 



watched the operation of making these balls, in company 

 with the engineer of the Forth Bridge. When the liquid 

 glass at a great heat was removed by the maker's rod it 

 cooled in the annealing quicker on the outside than in the 

 inside ; and after a skin was formed on the outside, small 

 cavities were suddenly seen in the inside ; and these 

 cavities sometimes, as in the case of quicksilver, joined 

 together into one large cavity when the ball was formed, 

 it was cut off from the stalk, and the cut surface was 

 ground smooth. One was exhibited without any internal 

 cavity ; this was formed with extreme care in the cooling. 

 Professor Tait remarked that care should be taken in 

 polishing the cut part, for he had no doubt that the 

 negative pressure in the cavities was enormous, and if 

 the slightest communication were made between the 

 outer air and the cavity, there would be a violent ex- 

 plosion. He also mentioned the trouble he had in getting 

 solid iron drops when the iron in its molten state is 

 gradually dropped in water. In the interior there were 

 cavities as in the glass. The engineer of the Forth 

 Bridge was of opinion that much more care should be 

 taken in the castings of iron for bridges and other 

 purposes, as any interior cavities excited a negative 

 pressure. No one was able to state definitely what was 

 in the cavities, but Professor Crum Brown suggested that 

 it might be carbonic acid absorbed from the glass in 

 cooling. ^^^__ 



LONDON MATHEMATICAL SOCIETY. 

 On Thursday, January 12th, Sir J. Cockle, F.R.S., 

 president, in the chair, the following communications 

 were made : — The Theory of Distributions — Captain 

 P. A. Macmahon, R.A. ; On the Analogues of the Nine- 

 Points Circle in space of Three Dimensions — S.Roberts, 

 F.R.S. ; On a Theorem Analogous to Gauss's in Continued 

 Fractions with applications to Elliptic Functions — L. J. 

 Rogers ; A Theorem connecting the Divisions of a certain 

 Series of Numbers — Dr. Glaisher, F.R.S. ; On Reciprocal 

 Theorems in Dynamics— Prof. H. Lamb, F.R.S. 



WOLVERHAMPTON LITERARY AND SCIENTIFIC 



SOCIETY. 

 Professor Norman Lockver, F.R.S., gave a lecture on 

 " Sun Spots," in the course of which he remarked that 

 on the earth the great variable element was the aqueous 

 vapour, which assumed so many different forms. In the 

 case of the sun the variable element was metallic gases, 

 such as iron, manganese, etc. The cause of the sun spot 

 was a downcast shaft or cyclonic depression, and where 

 there was a downcast shaft there must be a reaction or 

 an upcast shaft. When the falhng matter struck the sun 

 the reaction produced the red flames of hydrogen gas. 

 These rose not from the surface of photosphere, but from 

 the kernel. He added that the sun spots appeared in 

 cycles of eleven years' duration, which meant that they 

 began in a very small way, and at high latitudes. They 

 went on increasing in number and size as they drew 

 nearer the sun's equator. Observations commenced in 

 the year 1879, when there were very few spots, showed 

 that they consisted almost entirely of iron vapour. In 

 1884, when there were most spots on the sun, there was 

 no iron vapour at all, and later on there appeared the gas 

 of a metallic substance, for which they had no correspond- 

 ing gas on the earth — at least none that had been dis- 

 covered. When the sun spots had reached their maxi- 

 mum, as every telegraph operator knew, it was very 



difficult to get messages along the wires. This was owing 

 to the earth currents which no doubt spoke their own lan- 

 guage if they could be interpreted. Mr. Chambers had ob- 

 served that in one part of India the fall of rain during 

 the monsoon had a corresponding relative value to the 

 sun spots. The greater the area of the sun spots the 

 greater the fall of rain during the monsoon, and the 

 greater the fall of rain the cheaper rice became. 



EDINBURGH LITERARY INSTITUTE. 

 Sir Robert Ball, Astronomer-Royal for Ireland, recently 

 delivered a lecture on Comets. The lecturer dealt with 

 comets of all kinds and times, with shooting-stars and 

 meteorites. Comets, he explained, revolved in elliptical 

 orbits, and to accomplish the full length of their circuit 

 many of them needed such a length of time that they 

 could not repeat a visit to the earth. The closer the ex- 

 amination that had been made of comets, the more 

 apparent had it become that there was no solidity in 

 them. They were of extreme tenuity, and so light that 

 it had been found impossible to weigh them. People lived, 

 or had lived, in continual dread of a comet coming into 

 collision with the earth, and shattering it into fragments. 

 Collision between the earth and a comet occurred in 1861, 

 and because of the non-solidity of cometic matter this 

 world had sustained no damage. He mentioned that 

 carbon was largely found in the composition of comets, 

 and defined a shooting star as a small object moving 

 through infinite space. The opposition that met a shoot- 

 ing star when it entered the atmosphere of the earth 

 engendered a frictional heat, which in turn showed to 

 the world below a golden ball of fire. On a night when 

 the sky was full of shooting stars it had so happened 

 that the planet of the earth had got into a great cloud of 

 the bright illuminants. The knowledge which had been 

 gained about meteorites showed that in all likelihood 

 they had, ages ago, been thrown into space by very 

 powerful volcanoes, and that after wandering hither and 

 thither had happened again to come under the attractive 

 influences of their mother earth. Time was when 

 comets and shooting stars had been thought of ill-omen, 

 but nowadays we should rather look upon them as inter- 

 esting and beautiful visitors come to please and instruct, 

 but not to hurt and destroy us. 



MIDDLESEX NATURAL HISTORY SOCIETY. 

 At last meeting of this Society, Mr. Sydney T. Klein 

 read a paper on " The Appearance in London of Ephestia 

 Kuhniella and the Remedy Provided by Nature." The 

 insect referred to is a troublesome pest in the Mediter- 

 ranean ports, and in the spring of this year was discovered 

 in some large warehouses at the East end of London by 

 Mr. Klein. Fumigating with sulphur and the hot liming 

 of walls and floors were at once practised, but although 

 immense numbers of the imagos were destroyed, the 

 insects spread with great rapidity, until one warehouse 

 was literally smothered, and flour to the value of many 

 hundreds of pounds was so injured that it was unfit even 

 for cattle food. The ova are deposited generally on the 

 tops of the sacks of flour, and, speedily hatching, the 

 larvae at once burrow through the sack into the floor, in 

 which they spin long galleries of network which much 

 resembles wool. The larvae are full fed in about four 

 weeks, and then make their way out, swarming over the 

 floors and walls of the warehouse. Mr. Klein had a 

 colony at his private house for the purpose of experi- 



