March 30, 1882 | 
OMAR OC Lae 
507 
4. Prunus Cerasus (dwarf cherry) April 22 
5. Prunus Padus (bird cherry)... ... 0. 0 « hi oz) 
6. Pyrus communis (wild pear)... 0. 1. ve eg et 
7. Pyrus malus (crab apple) Ap ass 
8. Syringa vulyaris (lilac) ... are ee: May 4 
9. Lonicert tatarica (Tar'arian honeysuckle) ... op) 4 
10. Narcissus pocticus (poet's narcissus) ...  ... 9) 5 
11. Aes ulus hippocastanum (horse-chestnut) ... 3 7 
12. Crategus oxyacantha (hawthorn)... ... 0. 99 9 
13. Cytisus laburniwm (la‘ wnun) tas ten aj aS 
14. Sarothamnus vulgaris (common broom) _... ng awa 
15. Cydonia vulgaris (common quince)... ... yn LO 
16. Sorbus aucuparia (mountain ash)... ... 2. Ae 8) 
17. Sambu us nigra (common elder) ... res ng tS 
MMe SECUICIEZEAION UY) inne eee vees aes peers oe eS. 
19. Atropa belladonna (deadly nizght-hade) ae o5 23) 
20, Vitis vinifera (grape vine) ... ... «... ... June 13 
21. Tilia Europea ( grandifolia) (lime tree)... a7) PR 
22. Lilium candidum (white lily) on 
B.—FirsT FRuIT RIPE 
23. Ribes rubrum ... June 21 
24. Lonicera tatarica REMY coer Pacem Bane habe mel AIM eee 
PAS DSO OMS AUCUPIT ULE Panay \ esc, | ust) ieanh ices (ss SSO 
26. Atropa belladonnz ... Aug. 2 
Diss  SIADAIS LEAD “oc Wcoo Epo" Sob (hag nee po LE 
28. Aesculus hippocastanum.. ... .. .. «. Sept. 17 
Ooservations of the species 1, 3, 8, II, 17, 22, and 27 are 
specially requested, as on2 of the undersigned (Dr. Ihne) is at 
present occupied with the preparation of a phenological map for 
Europe. Observations made either this year or previously, but 
not yet published, should be sent to one of the undersigned, and 
will be esteemed a favour. In what way (27¢er adia) it is possible 
to utilise the observations, may be understood from the c »mpara- 
tive phenological map of Central Europe, by H. Hoffmann 
(Petermann’s Geographische Mittheilungen, january, 1881.) 
H, HOFFMANN 
Giesseo, February 25 Econ IHNE 
Rime Cloud observed in a Balloon? 
In the question whether the cloud that floated over Paris, 
January 25, consisted of microscopical atoms of solidified water 
or of minutest globules of liquid water cooled below zero, 
discussed under this heading in NATURF, vol. xxv. p. 337, 385, 
436, M. de Fonvielle adduces (p. 436) in favour of the first 
alternative a new argument, viz. that floating over the cloud in 
sunshine he has seen upon the cloud only the covora, and nothing 
resembling a rainbow, and he invokes the authority of Bouguer 
(1744), que ‘‘le phénoméne [la corona] ne se trace que sur les 
nuages formés de gouttes de vapeur et méme sur ceux dont les 
portraits sont glacée:, mais non sur les gouttes de pluie comme 
Vare-en-ciel.” 
I did not expect anything else. M. de Fonvielle could not 
see a rainbow, because the cloul certainly did not consist of 
rain-drops; neither could he see a rainbow, when the cloud 
consisted of minutest particles of liquid water. 
It is a well-known fact that small particles of water su-pended 
in air produce no rainbow. When Kratzenstein (1774) advocated 
the opinion anticipated by Halley (1686), that water-vapour may 
be condensed in a vesicular state, he availed himself of the 
observation, that in cloud, and mists, and the cond-nsed steam 
over boiling water, a rainbow is not to be observed in reflected 
light. Itis not necessary to enter into the question whether the 
hypothesis of mist-ve-icles is to be abandoned, and—as.seems to me 
more probable—the existence of very small solid (¢.e, not hollow) 
globules of liquid water is to be admitted for clouds, &c., con 
sisting of the latter; solil water-drops, to», if their dim-nsions 
are small enough in comparison to a wave-length of light, cannot 
cannot produce a rainbow, 
So I think it still possible that the cloud observed by M. de 
Fonvielle, and many mists, which have been described as con- 
sisting of ice, may have consisted of liquid water cooled below 
zero. 
__ In my letter in NATURE, vol. xxv. p. 385, read ‘‘ Hilde- 
_ brandsson’s discussion of the meteorological observations made 
_ during the voyage of the Vega” for ‘‘ Hildebrandsson’s meteoro- 
logical observations, &c.” ; and ‘‘ Frostr6z” (de. frost-smoke) 
instead of ‘‘ Frostz6g.”’ 
_ Heidelberg, March 11 
HERMANN Kopp 
Water in Australia 
THE extracts from Au tralian letters communicated by Mrs, 
Merrifield remind us again of the important question of water- 
supply in that thirsty rezion. Why need the crops be lost for 
lack of water, when accumulating evidence assures us that in the 
Tertiary Sandstone of the grea’ central plain there is an abun- 
dant supply not many yards from the surface? How can the 
great gun trees resist the drought as they do unless their roots 
touch water? Severa) successful borings have already been 
made, but probably such works far inland are prevented by the 
scarcity of fuel for steam power. Pro. Ayrton has now, how- 
ever, demonstrated tha: power cin be generated wherever col 
is plentiful, and transmitted economicelly and effectively by 
electric wire to the inlind motors. It is probable that within a 
few years the dynamo machine will prove of more practical 
value to Australia than to any other country in the world. If 
there is any novelty or any value in the suggestion of an under- 
ground water-supply in the Aus'ralian plains, and of obtaining it 
by the aid of electricity, the credit is due to Mr. Thomas Blunt, 
of Baxter-gate, Loughborough, not to myself. 
Bristol Hill, Leicester, March 25 F, T. Motr 
The Solar Spectrum in a Hail-Storm 
DuRING the hail storm of Tuesday, the 21st inst., I made 
observations on the spectrum in various parts of the sky, and 
was surprised to find the orange lines of a tint decidedly deeper 
than that of their normal hue. When the hail ceased and the 
snow began to fall heavily, the lines assumed their usual colour. 
The rain-band at the time was strong, as might have been 
expected. I was not before aware that hail would exert this 
influence on the spectrum The ob eryitions were made with a 
small pocket spectroscope. C. H, ROMANEs 
Worthing, March 22 
Temporary Retinal Effects 
In your present week’s ‘‘Notes” you have referred to the 
curious experiences of MM. Mace de Lepinay and Nicati, in 
finding the town lights appear green, after five hours among 
snow-helds. On the Cima di Jazi, some 16,000 feet or more 
high, I found another effect. On removing my blue snow- 
glasses, the sky (at about 10 a.m.) appeared of the deepest 
indigo colour, while the sun could be looked at without pain, and 
resembled a harvest-moon close to the horizon, of a red yellow 
tiat, and with a well-defined outline. The effect disappeared 
as we descended the mountain. As snother instance of tempo- 
rary affliction of the retina, I hai been u-ing on the sun, as 
examined with an §1-inch reflector, a miniature spectroscope 
with fine slit, notwithstanding which the spectrum was very 
bright. Some hours (not immediately) after, all the gas lamps, 
candles, &c, appeared of a blood red, and so continued for 
some hours. ‘This effect sti!l persisted at dinner-time, but 
gradually and entirely passed off during the meal. No trace of 
green tint was, in this case, seen. In the sun-glire it is not 
uncommon with some persons, to find leaves and other small 
objects on the path, of a red tint. J. RAND CAPRON 
Guildown, March 25 
Specific Heat and Thermal Conductivity 
Pror. TYNDALL, in his lectures on ‘Heat a Mode of 
Motioa,” p. 255, gives a highly-instructive experiment to illus- 
trate the influence of the specific heat of a substance in masking 
its thermil conductivity. Short prisms of iron and bi muth, 
having their upper ends coated with wax, are placed upona 
ves el of hot water, and the wax is observed to ielt first upon 
the bismuth, ia spite of its comparatively low conductivity. 
I should like to ask whether o'hers have been uniformly suc- 
cessful in obtaining the above resulr, at any rate when the bis- 
muth and iron prisms are soldered to the top of the hot water 
vessel; for this seems to me neces-ary in order that the experi- 
ment may be made with absolute fairness, and independently of 
any want of uniformity of poli-h and flatness in the surfaces 
between which the heat has to pass. 
T have tried with cylinders of nearly pure bi:muth and best 
bar iron of various lengths (from 1 cm, to 5 cm.) and diameters, 
brightly polished, and in some cases wrapped in vulcanised 
india-rubber, to avoid loss of heat by radiation and convection, 
and I invariably find that the wax melts upon the iron first. 
