190 



KNOWLEDGE. 



May, 1911. 



S.E., and the English Channel. \t several of the stations the 

 week was rainless. The amounts collected were as a rule 

 small, but at Tunbridge Wells 1 • 22 inches was collected in three 

 days. Sunshine was greatly in defect, except in Scotland N., 

 and in England N.W., where it was slightly in excess. In 

 England E. the district value was 12 hours (14%) as com- 

 pared with an a\erage of 34 hours (39%). The sunniest 

 stations were Stornoway and Douglas, each with 39 • 6 hours 

 (45%), while Guernsey reported 17-2 hours (20%), and 

 Eastbourne only 11-7 hours (13%). At Westminster the 

 total duration was 10-8 hours (12%). The mean temperature 

 of the sea-water ranged from 38° -6 at Cromarty to 47° -4 

 at Newquay. 



The weel< ended April 8th was very cold indeed, with but 

 little sunshine. Much snow was experienced in the southern 

 and eastern parts of England. Temperature was below the 

 average everywhere. In England S.E.the mean was 36" -9, or 

 8° -3 below the normal, a lower mean temperature than had 

 been recorded in this district, in the corresponding week, for 

 thirty-four years. Only in Ireland and the English Channel 

 was the district mean as high as 40"'. The highest maximum 

 (59°) was noted at Killarney, on the 2nd, and temperatures 

 of 58° were also reported from Cullompton and Wick. The 

 lowest readings came as a rule on the 5th, on which day a 

 temperature of 17' was recorded at West Linton. Frost 

 was reported at every station except Llandudno and 

 Donaghadee. The lowest reading on the grass was 14° 

 at Armagh and Markree. The total Rainfall was below 

 the average in all districts except the English Channel, 

 where it was just above the normal. At several stations the 

 week was rainless, and in Scotland N, the total fall was only 

 .about one-twentieth of the average amount. Sunshine was 

 deficient except in Scotland W. and England N.W. The 

 sunniest stations were Valentia 54-7 hours (61%) and 

 Falmouth 45-7 hours (51%). Westminster reported 26-0 

 hours (29%) and Birmingham only 10-3 hours (ll?/o). The 

 temperature of the sea-water varied from 37" at Scarborough 

 to 50° at Scilly. 



During the week ended April 15th, the weather was very 

 fine in most parts of these Islands, but with a good deal of 

 cloud in the North, Temperature was below the average 

 except in England N.E., and in Scotland, During the first days 

 of the week the maxima were very low generally, but a warm 

 spell set in, and towards the close of the week temperatures of 

 65" and 66° were recorded. The highest maximum was 68° at 

 Killarney on the 13th, but readings of 60° and upwards were 

 reported from each district except Scotland W., and the 

 English Channel, In the Channel Islands the maximum 

 did not exceed 58", and at Scilly it was only 55°, Frost 

 was recorded in each district except the English Channel, 

 and at Raunds and Llangammarch Wells the thermo- 

 meter fell to 23° ; at the latter station the thermometer 

 on the grass went down to 15°. Rainfall was in defect in all 

 parts, and many stations, including all those in England S.W., 

 were rainless. Sunshine was below the average in Scotland 

 and in England N.E., but above it elsewhere. Falmouth 

 reported the greatest amount, 68-2 hours (73 %), and Fort 

 Augustus the least, 14-1 hours (15%). At Westminster the 

 total duration was 34-7 hours (37%). The temperature of 

 the sea- water varied from 39° at Cromarty to 53° at Teelin. 



WEATHER INSURANCE.— An interesting application of 

 Meteorological Statistics for the purposes of Insurance is 

 announced by the Excess Insurance Co., Ltd., which offers 

 for a suitable premium to issue a " Pluvius Policy " under 

 which an agreed amount of money will be paid to any holiday- 

 maker, or other person, who experiences in any one week, over 

 a specified period, more than two days of rain, amounting in 

 each day to over 0-20 of an inch. The policy will in every 

 case specify the place, the record of rainfall at which is to 

 govern liability, together with an indication of the authority 

 keeping the record. In most cases the authority will be the 

 Town Clerk, or some observer recognized by the Meteoro- 

 logical Office, The rates are so arranged that a payment of 

 £l per week as premium will provide for £8 " compen- 



sation " should the rainfall amounts exceed 0-20 inch on more 

 than two days during the week. 



Policies must be taken out seven days before the period to 

 be covered commences. 



There are other forms of policy provided for. with \arying 

 rates, both of premium and of amount payable, but the under- 

 lying principle is the same in each. 



An obvious objection to the scheme is that it provides 

 " compensation " for loss or damage when no loss or damage 

 has, in fact, been sustained ; for, although a person whose 

 holiday is interfered with by rainy weather may have to spend 

 money in other and unexpected directions, and so suffer 

 pecuniary loss owing to the rainfall, there is nothing in the 

 scheme as announced to hinder anyone remaining, for instance, 

 in London and claiming "compensation" for rainy days in 

 Plymouth or Scarborough. In this way "insurance" may 

 conceivably degenerate into gambling and prove harmful. 



MICROSCOPY. 



By A. W. Sheppard, F.R.M.S., 



wit It the assistance of the fulloK'iiif> iiiicroscopists : — 



Arihur C. Bankiei-d. Arthur Eari.and, F.R.M.S. 



James P.urton. Richard T. Lewis, F.R.M.S. 



The Rev. E. W. Bowell, M.A. Chas. F. Rolsselet, F.R.M.S, 



Charles H. Caffvn. D. I. Scolrfield, F.Z..S., F.R.M.S. 



C. D. Soar, F.R.SI.S. 



LUMINOUS BACTERIA. — No phenomenon in nature is 

 so striking as the production of light by living organisms ; 

 considered either from the scientific or the popular point of 

 view it commands attention. The difiiculty experienced in 

 accounting for it is indicated by the fact that Darwin deals 

 with it under the heading of " Special Difficulties of the 

 Theory of Natural Selection." 



Light production occurs principally among marine animals, 

 but in these there are special organs involved. In the case of 

 bacteria which are light-producing, it is difficult to suppose 

 that special organs exist, they being minute uni-cellular 

 bodies, consisting essentially of a mass of protoplasm enclosed 

 in a cell wall; hence the possibility of a special light-produc- 

 ing organ is almost excluded. Light-production in living 

 animals is essentially different from that of inert chemicals or 

 of the phosphorescence produced by electrical means. 

 Phosphorescent chemicals in all cases have the power of 

 absorbing light and of re-emitting it either of the same, or of 

 a somewhat greater wave-length. Bacteria emit light which 

 is produced entirely by themselves, altogether independently 

 of anv extraneous light source ; in fact, they grow and produce 

 light better if kept entirely in the dark. In general, light can 

 only be produced by raising the temperature of a suitable 

 substance until it becomes luminous. It therefore follows 

 that a great deal of the energy so converted is lost as heat ; in 

 fact, to such an extent is this the case that an ordinary electric 

 lamp, even of the highest efficiency, does not give out in the 

 form of light more than about five per cent, of the energy 

 expended in raising the temperature of the filament. Bacteria 

 produce light which is unaccompanied by any heat radiations, 

 and so far as the investigations of the writer have yet 

 proceeded, there is no evidence that any in\isible radiations are 

 produced by them at all. Their efficiency as light-producers is, 

 therefore, extremely high, and were it possible to carry out on 

 a commercial scale the process of light-production as it occurs 

 in bacteria a tremendous step forward would be taken. 



Essentially, the process is an oxidation one, as in addition 

 to a nutritive material on which the bacteria may grow and 

 reproduce, a supply of oxygen is necessary. The natural 

 habitat of these organisms seems to be almost exclusively 

 .sea- water, or at least water such as is found in estnaries 

 where an appreciable quantity of saline matter is present. 

 They will grow and exhibit their light-producing properties on 

 an ordinary peptone-beefbroth gelatin medium, but they do 



