l62 



NA TURE 



[June 1 8, 1903 



knowledge. Another appendix deals with the proposed 

 explorations and investigations on a large scale, and is 

 contributed to by several well-known American men of 

 science. 



A siRiKiNG illustration of the enormous advance that has 

 taken place in chemical manipulation during the past two 

 or three years is afforded by a paper, in a recent number of 

 the Berkhte, on the " Evaporation and Boiling of Metal3 

 in Quartz-glass and in the Electric Furnace in the Vacuum 

 of the Kathode-light." Dr. F. Krafft there states that the 

 quartz tubes could be safely heated to 1200°, and with care 

 iip to 1400° C, even when exhausted to the low pressure 

 required for the production of the kathode-light in a vacuum 

 tube, and that even when containing metals they could be 

 safely taken from the furnace at 1200°, allowed to cool 

 in the air without annealing; and then replaced in the 

 furnace without any risk of fracture. By using an electric 

 furnace it was possible not only to regulate the tempera 

 ture within 2° or 3° between 18° and 1400° C, but also to 

 connect the quartz tubes to the pump by means of a ground- 

 glass joint made tight with wax, the wax remaining un- 

 melted although within a few inches of the hottest parr 

 of the furnace. 



The results achieved by the methods described in the fore- 

 going note were remarkable. The only vapour in the 

 quartz lube was that of the metal, which extended from 

 the surface of the liquid to the top of the furnace, above 

 which condensation took place. Under this almost in- 

 conceivably low pressure cadmium boiled at 420°, i.e. below 

 the boiling point of sulphur, zinc at 545°, and bismuth 

 below 1000°, the temperature of the furnace being about 

 T5o° above that of the boiling metal. Lead could be 

 rapidly distilled with a furnace temperature of 1180°, and 

 antimony at 775-780°. Silver began to evaporate fairly 

 rapidly at 1200°, but did not boil at 1340° ; copper showed 

 a distinct, though slight, evaporation at 1315°, but gold, 

 even at 1375°, the highest temperature reached in the ex- 

 periments, gave only a small mirror of silver, and below 

 it a tiny distillate of gold weighing less than 2 mg. It is 

 of interest to note that the boiling points in an absolute 

 vacuum of these metals, which probably lie at about 1400°, 

 1600", and 1800° respectively, are in the order of increasing 

 valency, and not in the order of their atomic weights. 



The additions to the Zoological Society's Gardens during 

 the past week include a Sooty Mangabey (Cercocebiis 

 fuliginosus), a Green Monkey {Cercopithecus callitrichus) 

 from West Africa, presented by Mr. C. S. Birch ; a Two- 

 spotted Paradoxure (Nandinia binotata), two Senegal 

 Touracous (Turacus persa) from West Africa, presented by 

 Mr. James Drew ; a Ring-tailed Coati {Nasua rufa) from 

 South America, presented by the Hon. Sibyl Edwards ; a 

 Patagonian Cavy {Dolichoiis patachonica) from Patagonia, 

 presented by Sir E. G. Loder ; a Common Quail {Coturnix 

 commutiis), British, presented by Mr. J. Woodward; an 

 Adanson's Sternothere (Sternothoerus adansoni) from West 

 Africa, a Pale Lizard {Agama pallida), an Egyptian Eryx 

 {Eryx jaculus), a Blunt-nosed Snake {Tarbophis obtusus), a 

 Schokari Sand Snake {Psammophis schokari), a Diademed 

 Sand Snake {Lytohynchus diadema) from North Africa, pre- 

 sented by Captain Stanley Flower ; a Stair's Monkey 

 (Cercopithecus stairsi) from British East Africa, a Green 

 ?>Ionkey {Cercopithecus callitrichus), an Eroded Cinixys 

 {Cinixys erosa) from West Africa, a Black-headed Lemur 

 {Lemur brunneus), a Grey Lemur {Hapalemur griseus) 

 from Madagascar, five Grey Monitors {Varanus griseus), 

 five Spiny-tailed Mastigures {Uromastix acanthinurus), 

 eight Ocellated Sand Skinks, a Corais Snake {Coluber 



NO. 1755, VOL. 68J 



corais) from South America, a King Snake {Coronella 

 gctula), a Mocassin Snake {Tropidonotus fasciatus) from 

 North America, a Carpet Python {Python variegata) from 

 Queensland, a Rhesus Monkey {Macacus rhesus, var.), two 

 Indian Rat Snakes {Zamenis mucosa) from India, deposited ; 

 a Burrhel Wild Sheep {Ovis iurrhel), an Axis Deer {Cervus 

 axis), born in the Gardens. 



OUR ASTRONOMICAL COLUMN. 



Connection between Sun-spots and Atmospheric 

 Temperature. — M. Charles Nordmann has recently completed 

 a discussion of the effect of sun-spots on the mean annual 

 temperature of the earth's atmosphere in tropical regions. 

 The period under discussion extends from 1870 to 1900, and 

 the method of discussion is analogous to that published by 

 Koppen in 1873, which dealt with the period 1830 to 1870. 



M. Nordmann has compared the mean annual variations 

 of temperature from the normal, as obtained from the 

 observations made at thirteen tropical stations situated in 

 various longitudes, with Wolf's numbers for sun-spot 

 frequencies during the same period, and from the two curves 

 obtained by plotting the two sets of numbers he has arrived 

 at the following conclusion : — " The mean terrestrial 

 temperature follows a period sensibly equal to that of solar 

 spots ; the effect of spots is to diminish the mean tempera- 

 ture, i.e. the curve which represents the variations of 

 temperature is parallel to the inverse curve of sun-spot 

 frequencies {Comptes rendus, No. 18). 



The Crossley Reflector of the Lick Observatory.— 

 This reflector, it will be remembered, was presented to the 

 Lick Observatory by Mr. Crossley, of Halifax, Yorks, and 

 contains one of the splendid mirrors made by the late Dr. 

 Common. It has an aperture of 3 feet, and a focal length 

 of 17 feet 6 inches. When remounted and used at Lick it 

 was found that the instrument was unsuitable for long 

 exposures on account of flexure and other defects, therefore 

 a new mounting has been devised and constructed by 

 Messrs. Harron, Rickard and McCune, of San Francisco, 

 and is' found to work satisfactorily. 



The polar axis is 14 feet long, and is so raised as to 

 allow the instrument to be used in all positions. As shown 

 in the accompanying illustration, this axis rests on two 

 piers, the northern one consisting of an inclined steel 



pillar, 8 feet high, resting on a concrete and brick found- 

 ation which is 6 feet high, whilst the bearing for the 

 southern end, carrying the altitude and azimuth adjust- 

 ments, rests directly on the brick and concrete foundation, 

 the downward thrust being borne by hardened steel balls. 

 The telescope tube is carried by the strong steel declination 

 axis, and the mirror is contained by a cast-iron cell in the 

 lower cylindrical section of the steel tube, whilst the photo- 

 graphic plate holder, with the usual adjustments, is placed 



