June 1 8, 1874] 



NATURE 



131 



Republic, accompanied by M. Deseilligny, the Minister of 

 Commerce, were present unofficially, and remained during 

 the whole process, appearing to take great interest in the 

 operations. The third of the larger ingots was melted on 

 May 7. 



The melting of the great ingot of 250 kilogrammes took 

 place on May 13, in presence of nearly every member of 

 the French Section of the Commission, of M. Struve from 

 St. Petersburg, MM. Stasand Hcusschen from Brussels, 

 M. Bosscha from Holland, Prof Miller and Mr. Chisholm, 

 delegates from Great Britain, and other foreign commis- 

 sioners. It was successfully accomplished with the 

 greatest facility and regularity, and without the slightest 

 hitch or accident. 



The dimensions of the cavity in the furnace, and con- 

 sequently of the large ingots produced, were as follows : — 



Metre Inch 



Length .. 1-24, or about 44 '9 



Breadth 015, „ 5'9 



Depth o'oy, „ 28 



Thickness of stone above the ) 



cavity I °'5 » 5 9 



The time occupied in the process was as follows : — 



2.10 P.M. — Furnace heated and lighted by degrees. 



2.24 „ — Furnace thoroughly heated. 



3.4 „ — Contents of metal (130 kilogrammes) melted 

 and bars begun to be introduced. 



3.27 „ —All the metal melted. 



4.15 „ — Metal entirely solid, but still at white 

 heat ; lid lifted. 



In about half an hour the mould was broken and the 

 ingot removed to the hydrochloric bath. When taken 

 out it was examined, and found, to all appearance, perfect. 



The stone used is so remarkably slow a conductor of 

 heat, that when the whole mass of metal was m a melted 

 state the upper surface of the stone was hardly warm, as 

 was tested by the hands of several of the persons present 

 being placed upon it. 



Portions of the three large ingots had been previously 

 tested and found to be very nearly indeed of pure plati- 

 num and pure iridium in the proportions of 9 to I. The 

 large ingot will also be assayed, and, if deemed neces- 

 sary, again melted, in order that the requisite homoge- 

 neity may be attained. 



'1 he work of constructing all the new line-standard 

 metres from this single ingot will at once be proceeded 

 with, and there will be sufficient surplus metal for making 

 first all the new standard kilogrammes, and then such 

 number of tnd-standard metres as may be required. 

 H. W. Chisholm 



T 



SOUNDINGS IN THE PACIFIC 

 HE voyages of the U.S. steamer Tiisca/wn, 

 Capt. Belknap, engaged in soundings for a cable 

 from America to Japan, have been already described be- 

 tween Cape Flattery and Oonalaska Island (vol. ix. p. 1 50), 

 and between California and the Sandwich Islands. They 

 have now been extended from the last-named station to 

 the coast of Japan. Sixty casts were taken at intervals of 

 about 50 miles. In the first 95 miles from Honolulu, the 

 depth increased at nearly 162 ft. to a mile, reaching 2,418 

 fathoms in lat. 21 "N., long. 1 59" 20' W. The average 

 depth of all the casts taken during this voyage was 2,450 

 fathoms. Between the mountains (all but one of which 

 are entirely submarine) the bed of the ocean was very 

 level; the greatest depth was found at lat. 22' 44' N., 

 long. 168' 23' E., 3,262 fathoms. These mountains were 

 as follows :— (1) Summit about lat. 20° 41' N., long. 171° 

 33' \V. ; height 5,i6olt. ; eastern slope 40 ft. and western 

 128 ft. to the mile. (2) Summit, lat. 21° 41' N., long. 176° 

 54' E. ; height 12,000 ft. ; eastern slope 37 ft. for about 

 127 miles and 51ft. thence to summit; western slope 



55 ft. (3) Summit 23° 45' N., long. 160° 56' E. ; height 

 9,600 ft. ; eastern slope 192 ft. ; western 204 ft. (4) Sum- 

 mit, lat. 23-' 55' N., long. 158= 7' E. ; height 6,000ft.; 

 eastern slope 60 ft.; western, inappreciable for 45 miles 

 from summit, afterwards 90 ft. per mile to its base. (5) 

 Summit above water, known as Marcus Island, lat. 24° 

 12' N., long. 153-' 57' E. Soundings 7 miles to north- 

 ward, lat. 24° 20' N., long. 154° 6' E., gave 1,500 fathoms 

 depth ; northern slope to this point 1,284 ft. to the mile ; 

 eastern slope thence, 200ft. ; western 157 ft. (6) Summit, 

 lat. 25° 42' N., long. 148" 39' E. ; height 7,800 ft. ; eastern 

 slope 163 ft. ; western 59 ft. From the base of the last 

 mountain to Port Lloyd, Peele Island, the upward slope 

 was 86 ft. to the mile. All the slopes are estimated at a 

 minimum. 



All specimens brought up from summits of mountains 

 or ridges were white coral or pieces of lava, and indicated 

 otherwise a hard and rocky bottom : all from the level 

 bed were of soft brownish-yellow mud. It will be noticed 

 that the position of Marcus Island has been hitherto in- 

 correctly indicated on the charts — too much to the north 

 and west. It is about 4 miles in length from east to west 

 and is thickly wooded and frequented by large ilocks of 

 birds. Another island laid down on the charts as some- 

 what to the southward of Marcus Island has no existence, 

 and the facts are similar in regard to several reported 

 shoals and recks indicated on the charts ; the Tiiscarora 

 sailed over their alleged positions, and found from 1,500 

 to 3,000 fathoms of water. 



Bottom temperatures, as in other parts of the Pacific, 

 range from 33 '2 F. to 34 '6 below i,Soo fathoms, what- 

 ever the additional depth. Between 1,200 and i,Soo 

 fathoms the temperature rises slowly to about 35"' at the 

 former depth. From 1,200 fathoms to the surface the 

 thermometer rose steadily ; suiface temperatures ranging 

 from 70° to 76° F. 



Observations on currents are made from a boat when 

 the sea is moderately smooth. For investigating deep 

 currents the sinker of the apparatus is of about 10 lbs. 

 weight ; it consists of four rectangular pieces of doubled 

 tin soldered at right angles to each other, each 6 in. 

 square, and with the re<.|uisite quantity of lead attached 

 in strips through holes punched in the lower edges of the 

 sheets. A small silk fishing-line supports the sinker, 

 running through the float, which is a wooden cube 5 in. 

 square at the surface by 4 in. in depth ; the line runs to a 

 reel in the boat, having a toggle placed on it just above 

 the float. For observing surface currents a similar sinker 

 is constructed of wood weighted to sink about 2 fathoms. 

 The line attached to it is marked in tenths of knots by 

 small corks, which also prevent errors that would other- 

 wise accrue by the line sinking. 



A fixed point of departure is obtained by lowering the 

 sounding apparatus and bringing the sounding wire in a 

 vertical position after bottom is reached. From this point 

 the current-measuring apparatus is thrown overboard, and 

 its rate and direction of progress measured at frequent 

 intervals of time. The small errors due to friction are 

 easily eliminated, and the elements of calculation are ex- 

 ceedingly simple. An approximate method of obtaining 

 the surface current when dredging is by anchoring the 

 boat to the dredge lines as a fixed point. In deep cur- 

 rents the float is vertical over the sinker. 



The voyage occupied twenty-eight days, and the weather 

 was exceptionally favourable. There are only sixty-five 

 inhabitants on Peele Island, and the 1 uscarora was the 

 first visit of a naval vessel for more than seventeen 

 years ; Commodore Perry stopped at the island in 1853. 

 A Mr. Savory, formerly a whaler, from Massachusetts, 

 had exercised the functions of governor, consisting princi- 

 pally of presiding over marriages and funerals, for many 

 years, and died last March at the age of eighty, a Mr. 

 Thomas Webb succeeding to the position and honours. 

 In 1827 Capt. Beechy, R.N., took possession of the islar.d 



