548 



A'A TURE 



[August S, 1895 



in which all the functions of the protoplasni arc cjuiesccm, but i 

 from which they re\'ive when again placed in conditions suitable | 

 for germination. The immunity from injury appears to depend \ 

 on the protoplasm of the seed passing into a completely inert I 

 >late, in which it is inca|xible of either respiring or assimilating, 

 liefore exposure to the unfavourable conditions. The period of , 

 suspende<l animation may e.\tend over an indefinite lime, prob- 

 ably through a long series of years, and the seeds may during 

 this perio<l be subjected to very low temperatures without de- 

 stro)-ing their vitality. Those above mentioned were exposc<t, 

 in a refrigerator, as many as Ii8 times in succession, to a sudden 

 cooling to temperatures varying between -30° and -S3'C., 

 without injurious effects. On the other hand, seeds of the 

 sensitive plant and of Lobelia Eriiins succumbed, for the most 

 |jart, to similar treatment. These statenients have an important 

 liearing on the question of the retention of their vitality by buried 

 seeds. 



The additions to the Zoological Society's Gardens during 

 the past week include a Macaque Monkey (Afacaiiis •yiiama/^iis) 

 from India, presented by Mrs. Herman Schlesenger ; a Rhesus 

 Monkey {.Vaiaciis r/tisin) from India, presented by Miss 

 l-'olhurst ; a Macaque Monkey (Afattuiis iyiioHio/giis) from 

 India, three .Slow Lorises {Afyi/i,</nis lardigradiis) from 

 Sumatra, presented by Mr. Stanley S. l-lower ; a deoffroy's 

 Marmoset (Midos geoffroii) fron> Panama, presented by Miss 

 Mina Sangiorgi ; a Green .Monkey (Cercopitludis callitrichtis) 

 from West .\frica, presented by .\ldlle. Eugenie Grobel: a 

 liarljary Ape {Afaiaiiis iiiiiiis) from North .\frica, presented by 

 Mr. Edwin Fletcher : two Crested rorcupines(/yi'.f//7.v<>/.f/ato), 

 two Cape Zorillas(/.7<;H_j'.v zorilla) Uom South .\frlca, presented 

 by .Mr. J. E. .Matcham : a Ducorp's Cockatoo (Coi-a/HH dmorpsi) 

 from the Solomon Islands, presented by Mrs. Dexler; a 

 Nightjar (Ca/»r/;7/«4'"-' eurofhcm), European, presented by Mr. 

 T. West Carnie ; two Robbcn Island .Snakes (Coronel/a pho- 

 (arum) from South Africa, presented by .Mr. Barry McMillam ; 



a Chameleon (ChamitUoii hasilhius) from Eg)pt, 



presented by Mr. J. Buchanan ; a Brown Capuchin {Cchis 

 J'aliiUlus) from Guiana, a Black-liacked Jackal (C<J//*> "/«««'<•/«.>) 

 from South Africa, six King-tailed C<jatis {Nasiia nifa) from 

 .South America, deposited ; a Red River Hog (Polanioihirrus 

 penicillalus) from Wc-st Africa, a Sooty I'halanger (Phalaiigisla 

 /iiliginosa) from .\ustralia : a l)c l-'ilippi's Meadow Starling 

 {Sturiiel/a dcfilippi) from I^ Plata, purchased : t«o Manelarin 

 I)ucks (./;> gaicriciilala), seven Summer Ducks (. /-..i sfoiisa), 

 three Chilian Pintails (Dofila spinicaiida), bred in the Gardens. 



OUR ASTRONOMICAL COLUMN. 



Thk Rotation ok VKNt;s. — Not willistamling the persistence 

 with which the planet \'enus has l>eeii telcscopically observed, 

 ihe [leriwl of rntatiun is still undetermined with anything like 

 rcrtainty. Schroter l>elieved the time of rotation to be 23h. 2Ini. : 

 anil this i)eriiKl, or iherealKiuts, was pretty generally arlopled until 

 the announcement by Schiaparelli. m 1890, that the lime of rota- 

 lion was (mibably e<)ual to lh.1l of the planet's revolution riumd the 

 sun, that is, alwut 225 ilays. This conclusion was based on the 

 rigidity of the markings at different hours of the day and fur weeks 

 together. ( Jbservatinns by M. Perrotin and Dr. Terby tend |i. 

 strengthen the conclusion arrived at by Schiaiiarelli. t)n Ihe 

 lither hand, M. Niesten observed the planet between 1881 and 

 1890, and found that a periixl of 23 hours satisfied his observa- 

 tions ; while M. Trouvclot, from nearly twenty years' work, 

 concluded that the rotation [icriod was alioiit 24 hours. In this 

 divided stale of opinion, therefore, it is evident that much 

 remains to Ix: done Iwfore any sitisfaclory cfmcluslon can lie 



awn. ■ 



During the present year, Mr. Brenner, of the Manors 

 ( »l»crvalory, has olwcrveil the planet as frequently as jxissible 

 .since .\pril 17 (.-hi. Xatli. 3300). His first observalions of a 

 bright and a dark .s|>ot near the north |i<)le led him to agree wilh 



NO. 1345. VOL. 52] 



Schiaparelli, but further observations have changed his opinion, 

 and he now believes the period to be about 24 hours. On July 2 

 he announced that a marking near the southern cusp had been 

 visible since June q, but became in\isible about 4 p.m. each 

 day, while a well-marked streak appeared about 8 p.m. Olher 

 marks also ajijieared and disappeared in a manner inconsistent 

 with a rotation period of more than 24 hours. One of the most 

 important of the markings, though noted quite independently, 

 appears to be i<lentical with one observed by Mr. Stanley Wil- 

 liams eleven years ago : in a communication to Mr. Brenner, 

 .Mr. Williams states: "In 1SS4 I managed to .secure about 

 one hundreil sketches of the markings on ^'enus. These mostly 

 favour a rotation of about 24 hours : but there was one strongly- 

 marked indentation near the southern horn, which remained 

 visible continuously for about a monlh. It was prolonged on 

 the disc by a narrow and unusually dark and definite streak (for 

 \'enus)." Mr. Brenner has since claimed lo have proved wilh 

 cerlainty that \'enus rotates in about 24 hours : some of Ihe 

 markings return regularly at Ihe same hour of Ihe day, and are 

 invisible at other times, when the definition is ec|ually good : and 

 it is even possible lo observe Ihe appearance and advancing of 

 Ihe most conspicuous streak. 



Gkodeticai. Observaiions. — Dr. Geelmuyden, of Chris- 

 liania, has recently published the results of a comiiiirison between 

 the astronomical and geodelical determinations made in Ihe 

 course of a Iriangulation of Norway. The stations selected for 

 oliservation lie between 59^ and 64° lal , and Ihe astronomical 

 work connected with the investigation was conducted under Ihe 

 direction of the late Prof Kearnley, extending as far back as 

 186S. The observations refer to measurements made at eleven 

 stations, of which nine have both the a/imulh and latitude 

 determined, and two the diflerence of longitude. 



As origin for the geodelical survey, the geographical coordi- 

 nates of Dragonkollen, a station on the Swedish border, have 

 been chosen, partly because its position is particvilarly well 

 determined, but principally on the ground that iis situation 

 points to Ihe existence of a very small local attraction, .\ssuniing 

 that for this station a vertical line coincides with the normal of 

 Bessel's ellipsoid, Dr. tieelmuyden has conqnUei.1, with the data 

 already collected in Ihe course of the geodetic survey, Ihe devia- 

 tions of the plumb-line for the other stations, in which both the 

 azimuth and the latitude have been dclermined. Tlie results are 

 show n in the follow ing table : — 



Station. 



I >itrereiice 

 of 

 I azimuth. 



Jonsknuden . . . 



Gausta 



Musbergoen ... 



Chrisliania 



Hogcvarde 



Hoslbjorkampen 



Na'verljeld 



Gien ... 



Graakallen 



Norberghaug ... 



+ S-S5 



- 6 33 



- 072 



- 3-87 



- i3'oo 

 + 6-40 



+ 4 '49 

 - 1072 



- 7'7i 



- 670 



The deviations of the plumb-line here shown, agree on Ihe 

 whole with what might be ex|X-cted from the confcirmation of 

 the surface and the contiguity of neighbouring mountains. I'or 

 example, ihe westerly deviation of Cden can be explained liy the 

 attraction of Dovrefjeld. An exception is, however, met in the 

 rase of NorlK-Tgh-iug, where an easterly rather than a westerly 

 deviation would have been exix;cled. .\ map is allached, in 

 which is shown bolh the position of the several .stations and ihc 

 direction of the deviation of Ihe iilumb-Iine. 



TffE INSTITUTION OF MF.CHANICM. 

 ENGINF.F.KS. 

 \\V. annual summer meeting of the Institution of Mechanical 

 Engineers was held in Glasgow lasl week, under the chair- 

 manshipof the President of the Inslitutiim. Prof. Alexander H. 

 W. Kennedy, K.R.S. .\ strong local comniitlee had been 

 organi.sed under the chairmanship of Sir Kenny Watson, Prof. 



T' 



