SCIENTIFIC NE^VS. 



[Mar. 36J "iS 



material. The object of heating the coil is to vapourise 

 the oil which passes through it, and as soon as the vapour 

 issues from the end of the coil it is lighted, and then 

 there is a very powerful light. The flame heats the 

 coil, so that after the first heating with cotton waste, etc., 

 the whole operation is automatic so long as a sufficient 

 working pressure is maintained in the drum. We 

 understand that the air pump has to be worked about 

 every two and a half hours, and that vinith a 500 candle- 

 power light the charge of oil will last about thirteen 

 hours. The oil consumed for a lamp of this power is 

 said to cost only sixpence per hour. 



Lamps of this kind are not only powerful, but port- 

 able, and as the cost of the oil used is moderate, it is 

 probable that they will be used extensively. The inven- 

 tor of the lamp we are now describing is Captain Doty, 

 who is well known in connection with the introduction 

 of mineral oils for lighthouse illumination. The makers 

 are Messrs, Braby and Co., of 362, Euston-road, 

 London. 



SOCIAL ANIMALS. 



AMONG the very lowest animals society begins by actual 

 physical fusion, accompanied very soon by physio- 

 logical division of labour. In societies of the highest 

 animals there is no physical differentiation, except such 

 as depends upon age or sex, and the bond of cohesion 

 concerns the instincts only. A middle term is furnished 

 by the social insects, where the physical differentiation is 

 sufficiently strong to produce at least a third (the so- 

 called neuter) sex, while the instincts are at the same 

 time powerfully affected, so that self-sacrifice to the 

 extent of death or mutilation in the common cause is 

 felt as a less evil than infringement of the cardinal social 

 rules. 



In rude societies, whether of men or of animals, the 

 first necessity is cohesion. Right or wrong, the voice of 

 the community, or the royal word of command, must 

 be obeyed and enforced. The bee exercises no right of 

 private judgment in the presence of the swarm. When 

 the queen flies to a bough the workers fly there too. If 

 she flies down a cottage chimney or into the deadly 

 fumes of a lime-kiln, the workers are bound to keep 

 her company. Where the train of ants goes every one 

 must follow, and they will face fire and water rather 

 than desert the track. Bees and ants illustrate the 

 best, because, in the simplest way, the prime essentials of 

 the social state. In them virtues profitable to the com- 

 munity are generated by social conditions and adaptation 

 thereto, without abstract reasoning or reflection. The 

 laws of conduct which govern the hive or ant-hill are 

 based upon long experience of utility, but they are 

 obeyed with exemplary indifference to the immediate 

 happiness or misery of the individual. 



It is for the naturalist to point out how eminently 

 successful this policy has proved in a world of selfish 

 competition. Bees, wasps, and ants — that is the 

 peculiarly social insects — are almost world-wide in their 

 range. They are also extremely numerous in species, 

 and in all other respects must be counted as con- 

 spicuously dominant forms. Their success as a compet- 

 ing form is evinced by the number of plausible imita- 

 tions which they have called forth. There are Diptera, 

 Hemiptera, and Lepidoptera, which assume the black 

 and yeOow rings, while certain of the Lepidoptera have 



even changed their plumed wings for nearly clear ones, 

 in order more closely to resemble the wasp, or hornet, 

 or bee. Ants again are mimicked by spiders. No 

 doubt these base imitators escape attack by their resem- 

 blance to creatures which have stings or formidable 

 jaws, and which are instructed by a long established 

 social instinct when and how to use them with effect. 

 In other cases the mimicking forms use their deceptive 

 exterior to escape detection when making their way to 

 the stores of food laid up by the colonies. Perhaps the 

 gnats and mosquitos, whose social relations are rudi- 

 mentary, may even exceed in numbers the truly social 

 hymenoptera and orthoptera, but they get far less en- 

 joyment out of life. The finest fields of industry open 

 to insects are occupied by the well-organised societies. 

 In a world where competition rules supreme, it is the 

 social tribes which come to the top. 



STORMS.— IV. 



(^Concluded from page 2\ti,.") 



THE following are the sailing instructions recom- 

 mended by the U. S. Hydrographic Office, referred 

 to in connection with fig. 5, and we regret that by an 

 oversight they were omitted in our previous number : — 

 With an east wind, changing to southward, heave to 



on the starboard tack. 

 With an east wind, changing to northward, run west 



north-west or heave to on the port tack. 

 With an east south-east wind, changing to southward, 



heave to on the starboard tack. 

 With an east south-east wind, changing to eastward, 

 run to the north-west or heave to on the port 

 tack. 

 With a south-easterly wind, changing to southward, 



heave to on the starboard tack. 

 With a south-easterly wind, changing to eastward, run 



north north-west or heave to on the port tack. 

 With a south south-easterly wind, changing to south- 

 ward, heave to on the starboard tack. 

 With a south south-easterly wind, changing to east- 

 ward, run north or heave to on the port tack, and 

 so on round the compass. 

 The above courses are for the wind two points on the 

 starboard quarter ; but, if sea and wind permit, bring 

 the wind broad on the quarter. If in either of these 

 positions there be danger of broaching to, run before the 

 wind until more moderate, and then bring wind on star- 

 board quarter. 



A ship having the wind steady is on the storm-track, 

 and should run before the wind ; note the course and 

 keep it. 



The Colour of the Eyes. — M. de Candolle, a French 

 investigator, has come to the conclusion from his re- 

 searches that women have a larger proportion of brown 

 eyes than men. He also finds that when both parents 

 have eyes of the like colour, the chances are 88 to 12 that 

 their children who arrive at the age of ten years (when 

 the colour of the eyes is fixed) will have eyes of the same 

 colour. When the parents have eyes oi different colours, 

 the chances are 55 to 45 in favour of brown as against 

 blue or grey eyes in the children. He is also of opiniori 

 that the health of the brunette type is, as a rule, superior 

 to that of the blonde type. 



