152 



NATURE 



\August II, 1887 



ealled themselves the Tumu. At the confluence of the Douglas 

 River with Deception Bay, a fourth, the Moko tribe, was found. 

 The Kiwa Fori tribe, the fifth met with, were ascertained to be 

 the inhabitants of the country close to Bald Head, in the Papuan 

 Gulf. The Birumu tribe were seen about 16 miles north-west 

 of Bald Head, and the Evorra, the seventh and last tribe, were 

 found about the same distance nonh-east from Bald Head. 

 With all, except of course the first, friendly relations were esta- 

 blished. Mr. Bevan's previous experience of New Guinea 

 Batives and knowledge of some of their habits and dialects were 

 exceedingly setviceable to him ; and with the exercise of a little 

 patience he was enabled to inspire them with the fullest con- 

 fidence. Several natives were induced to go on board the 

 steamer, and were photographed. Only three of the tribes 

 could be spoken of as large, the one possessing the greatest 

 numerical strength being th2 Kiwa Pori, which numbered from 

 400 to 500 men. The result of Mr. Bevan's observations is 

 that the country is practically uninhabited except along the 

 coast. No natives were seen on the Jubilee River beyond 25 

 miles from the coast-line. 



The best of the land — and fine rich soil it is — appeared to lie 

 between the head of the deltas of both rivers and the foot of the 

 hills, where it looked exceedingly fertile, and covered in places 

 with a palm scrub which could be readily cleared. Sago, 

 tobacco, bananas, bread-fruit, and sugar-cane were found to be 

 indigenous. As already stated, the country about the deltas is 

 alluvial and flat, and then in turn come sandstone, limestone, and 

 ironstone, as well as the stratified rocks which mark the earlier 

 geological periods. Mr. Bevan hopes, at no distant date, to be 

 able to complete the work of which this preliminary expedition 

 he has now made is but the precursor. In the animal, vegetable, 

 and mineral kingdoms, there is a splendid field for men of 

 science. About eighty ornithological specimens have been 

 obtained by the party, and a few snakes, lizards, and fishes, 

 which will be exammed at the Australian Museum. A large 

 and varied ethnological collection has also been obtained by Mr. 

 Bevan in exchange for trade from the tribes with whom he 

 established friendly intercourse. Some of the prominent features 

 in the landscape have been named after Mr. Richard Wynne, 

 Mr. F. E. Joseph, Dr. Ramsay, Messrs. Harrie Wood, C. S. 

 Wilkinson, E. Fosbery, and other well-known Sydney citizens. 



A word is necessary with regard to the climate, which is 

 described as by no means unhealthy. The temperature varied 

 from 72° F. at daybreak to about 86° in the shade at noon. 

 The party returned to Thursday Island within the time stipu- 

 lated by the owners of the Victory, in excellent health, and with 

 unimpaired physique. The cost of the expedition was from 

 ;^5oo to ^600, but from this a considerable sunn, repre- 

 sented by the value of the collections, must be deducted. In 

 response to Mr. Bevan's application, the Government have placed 

 at his disposal a competent draftsman to aid him in making up 

 his plottings. 



THE INSTITUTION OF MECHANICAL 

 ENGINEERS. 



'T'HE Institution of Mechanical Engineers held their summer 

 ■*■ meeting last week, at Edinburgh, under the presidency of 

 Mr. E. H. Carbutt. The meetings were held in the Library 

 Hall of the University, the members being received by the 

 Marquis of Tweeddale, the chairman. Sir William Muir, Prin- 

 cipal of the University, and other members of the Reception 

 Committee. The two papers first read on Tuesday related to 

 the Forth Bridge and the machinery employed in its construc- 

 tion. Both papers we reprint to-day. The discussion on the first 

 of them referred mainly to the subjects of expansion and contrac- 

 tion under variations of temperature and to wind-pressure, and 

 in reply the author of the paper, Mr. E. M.Wood, explained that 

 \\ inches per 100 feet was allowed for expansion, or double the 

 amount usually thought sufficient ; whilst, as regards the wind- 

 pressure, the highest registered had been 35^ lbs. per square foot, 

 whilst 56 lbs. was allowed for. All the speakers who discussed 

 the paper of Mr. Arrol, the contractor for the bridge, referred 

 in high terms to the skill and ingenuity exhibited throughout. 

 Later on in the day the members made an excursion to the Forth 

 Bridge, Mr. Arrol and the heads of the various departments at 

 the works acting as guides. A striking feature was the com- 



parative noiselessness with which the work was carried on, 

 owing to the successful use of hydraulic power in riveting. 



We regret to learn that on the day of the visit to the bridge 

 two men had lost their lives owing, it is believed, to the staging 

 on which they were employed giving way ; this raises the number 

 that have been killed at the Forth Bridge works to six during 

 the last two months, the number of men employed averaging 

 between 30CO and 4000. 



The third paper read was by Mr. F. J. Rowan, on electro- 

 magnetic machine tools, which were invented by him to over- 

 come the difficulties of riveting by hand ; they perform their work 

 in a very complete way. The conditions of the work itself 

 involve the separation of the riveting portion of the apparatus 

 from the bolster or holder-up, whilst the riveting process requires 

 that the two portions of the machine should be rigidly held to- 

 gether. This is effected by magnets s > arranged on opposite 

 sides of the plating with their poles of unlike denomination 

 facing each other, that they are drawn towards each other, thus 

 pressing the plates together, and insuring the proper condition 

 for riveting. The riveting itself is effected by an electric 

 motor, which by means of gearing and a cam, lifts the hammer 

 against a spring, the amount of compression imparted to the 

 spring in lifting being regulated by hand. 



The first paper read on Wednesday was descriptive of the 

 electric light on the Isle of May, by Mr. D. A. Stevenson. 

 The machinery, boilers, and engines, are placed near the base of 

 the island, and close to the water-supply, as it was found that 

 the saving which would be effected by not having to convey fuel 

 to the top of the island, or to pump up water, would compen- 

 sate for the loss of energy due to the resistance of extra length 

 of the electric conductor. The electric generators are two 

 De Meritens alternate-current machines, each weighing 4^ tons. 

 The induction arrangement of each machine consists of five sets 

 of twelve permanent magnets, sixty in all, each magnet being 

 made up of eight steel plates. The armature, 2 feet 6 inches 

 in diameter, is composed of five rings with twenty-four bobbins 

 on each, arranged in groups of four in tension and six in 

 quantity, and makes 600 revolutions per minute. W^ith the circuit 

 open, each machine develops an electromotive force of 80 volts, 

 with the circuit closed through an arc 40 volts. An average cur- 

 rent of 220 amperes is developed, thus yielding 8800 watts of 

 electrical energy, or 117 horse-power in the external circuit. In 

 the dioptric arrangement constructed by Messrs, Chance to the 

 author's design, the condensing principle has been carried further 

 than in any apparatus previously constructed. The principle 

 consists in darkening certain sectors by diverting the light from 

 them and throwing it into the adjoining sectors so as to reinforce 

 their light. The author agreed with the conclusion arrived at 

 by the Trinity House that taking first cost and annual main- 

 tenance into account, electricity should only be used for im- 

 portant landfall-lights ; where, however, the most powerful light 

 was desired, independently of cost, the electric arc had no rival. 

 Some interesting observations have been carried on for the last 

 five months which prove the electric light to be the most pene- 

 trating of all lights in all states of weather. Every night at 

 twelve o'clock the light-keepers at St. Abbs Head, twenty-two 

 miles distant, where there is a first-order flashing light, and one 

 of the most powerful oil-lights in the service, observe the Isle of 

 May light ; whilst the keepers there observe the St. Abbs Light. 

 The result of these observations has been that the Isle of May 

 light has been seen one-third more frequently than the other. 

 The paper was discussed by Sir James Douglas and several other 

 speakers. A paper was read on the construction of the Tay 

 Viaduct, by Mr. F. S. Kelsey, the resident engineer. This bridge 

 is two miles long, and has taken five years to construct, having 

 been opened for traffic on June 20 last. A paper on the dredg- 

 ing of the lower estuary of the Clyde, by Mr. C. A. Stevenson, 

 was read. Both these papers, which were fully discussed, are of 

 technical rather than scientific interest. 



In the evening a conversazione was given by the Lord Provost, 

 magistrates, and Council of the city in the Museum of Science 

 and Art. Sir William Thomson gave a very exhaustive lecture 

 on waves, concluding with an important suggestion. It seemed 

 to him that inasmuch as wave resistance depends almost entirely 

 on surface action, it might be diminished relatively very much 

 by giving a great deal of body below the water-line. High 

 speeds of 18 or 20 knots might thus be obtained. By making 

 ships like the old French ships, swelling out below the water- 

 line, there would be a large additional displacement and carrying 

 power, and little addition to wave disturbance. 



