July 20, 1882] 



NATURE 



2 73 



a minimum of those risks of fire which are inherent to 

 every system of artificial illumination. They point out 

 that the chief dangers of every new application of elec- 

 tricity arise mainly from ignorance and inexperience on 

 the part of those who supply and fit up the requisite plant. 

 The difficulties that beset the electrical engineer are 

 chiefly internal and invisible, and they can only be effec- 

 tually guarded against by "testing" or probing with 

 electric currents. They depend chiefly on leakage, undue 

 resistance in the conductor, and bad joints, which lead to 

 waste of energy and the production of heat. These 

 defects can only be detected by measuring, by means of 

 special apparatus, the currents that are either ordinarily 

 or for the purpose of testing, passed through the circuit. 

 Bare or exposed conductors should always be within 

 visual inspection, since the accidental falling on to, or the 

 thoughtless placing of other conducting bodies upon such 

 conductors might lead to " short circuiting" or the sudden 

 generation of heat due to a powerful current of electricity 

 in conductors too small to carry it. 



The Committee point out that it cannot be too strongly 

 urged that amongst the chief enemies to be guarded 

 against are the presence of moisture and the use of 

 "earth " as part of the circuit. Moisture leads to loss of 

 current and to the destruction of the conductor by electro- 

 lytic corrosion, and the injudicious use of " earth " as a 

 part of the circuit tends to magnify every other source of 

 difficulty and danger. 



The chief element of safety is the employment of skilled 

 and experienced electricians to supervise the work. 



The rules deal with the installation of the dynamo- 

 machine, the fixture of the wires, the character of the 

 lamps to be used, and the danger that accrues to the 

 person. 



To secure persons from danger inside buildings, it is 

 essential so to arrange the conductors and fittings, that 

 no one can be exposed to the shocks of alternating cur- 

 rents exceeding 60 volts ; and that there should never be 

 a difference of potential of more than 200 volts between 

 any two points in the same room. 



If the difference of potential within any house exceeds 

 200 volts, whether the source of electricity be external or 

 internal, the house should be provided outside with a 

 " switch," so arranged that the supply of electricity can 

 be at once cut off. 



The rules are very valuable, and should be obtained by 

 all those who are contemplating the use of the electric 

 light. 



PROF. HAECKEL IN CEYLON* 

 II. 



IN the July number of the Deutsche Rundschau, Prof. 

 Haeckel gives a further account of his stay in Ceylon, 

 a stay which his ardent enthusiasm and unwearied in- 

 dustry cannot fail to have made fruitful in results to the 

 scientific world. The present series of papers being 

 intended for magazine readers in general, is, as might 

 be expected, altogether popular in tone. The Professor's 

 researches and discoveries in support of the theory of 

 Evolution, are only implied, not described in detail. 

 His letter is written from the point of view of an intelligent 

 and cultivated traveller, fully alive to the novelty and 

 beauty of the scenes in which he found himself, and of a 

 naturalist anxious to make the most of his very limited 

 time to become familiar with the fauna and flora of that 

 lovely island which Buddhist poets gracefully apostro- 

 phise as "a pearl on the brow of India." The energetic 

 Professor was evidently a subject of much wonder to the 

 languid Anglo-Indians and lazy Singhalese, as, in his 

 white linen suit and " Sola" hat, he braved the mid-day 

 sun and even occasionally the tropical rains, besides 

 setting at nought the bites of countless leeches and the 



Continued from p. 256. 



stings of mosquitoes and scorpions, and prosecuted his 

 researches from morning till night. It is, however, to 

 this constant bodily exercise and to his invariably tem- 

 perate diet, that Prof. Haeckel ascribes his perfect health 

 while on the island ; but it is doubtful whether, as the 

 body became enervated by the climate, such habits could 

 be long sustained. 



The first, and one of the most delightful excursions 

 made by Prof. Haeckel in Ceylon, consisted in a visit to 

 a Singhalese village called Kaduwella, situated on the left 

 (southern) bank of the Kalany, about ten miles from 

 Colombo. The party from Whist Bungalow, joined by 

 their fellow countrymen residing at the neighbouring Elie 

 House (formerly the residence of Sir J. Emerson Tennent) 

 drove to the appointed place in the little one-horse 

 carriages universal in Ceylon, which are drawn by 

 brisk Burmese ponies, whose speed is superior to their 

 staying powers, ten miles being quite sufficient to tire 

 them out. Horses are rarely used in Ceylon, except in 

 spring carriages, and are almost all imported from the 

 Indian mainland, or from Australia ; European horses 

 cannot survive the climate. Bullocks may be said to be 

 the only animals of draught or burden, and Prof. Haeckel 

 mentions the long string of bullock carts, some single, 

 some double, which are constantly met on the road ; "the 

 bullocks all belong to the class of the Zebu or humped 

 oxen of India {Bos iiiduus), but there are many varieties ; 

 one of the smaller kinds is very swift and agile." ' 



Prof. Haeckel notes as among the most beautiful effects 

 of the Ceylonese lowlands through which the road to 

 Kaduwella lies, the middle place which they occupy 

 between garden and forest, between cultivated and un- 

 cultivated nature." Surrounded by majestic trees, all 

 overhung and overgrown with creepers and climbers, one 

 might often imagine oneself in the midst of the wildest 

 forest ; but a little hut almost hidden beneath a bread- 

 fruit tree, a dog or a pig issuing from the brushwood, 

 children playing hide and seek behind the caladium 

 leaves, serve to remind us that we are in fact in a Cey- 

 lonese garden. The real forest, on the other hand, which 

 is closely adjacent, with its manifold juxtaposition of 

 every variety of tropical trees, with its orchids, cloves, 

 lilies, malvaceae, and other lovely flowering plants, shows 

 all the variety and apparent design of a costly pleasure 

 garden. This singular mixture of nature and culture is 

 visible also in the human accessories of these forest- 

 gardens; for so great is the simplicity of the dwellings 

 and the clothing of the Singhalese inhabiting them, that 

 although the descendants of an old and cultivated race, 

 there is little in their appearance to distinguish them 

 from mere savages." Arrived at Kaduwella, after a halt 

 and refreshment at the Rest-house (the government sub- 

 stitute for hotels, which are altogether wanting in Ceylon 

 except in the chief towns), Prof. Haeckel made his first 

 attempt to penetrate an Indian jungle, with what success 

 his own words must tell : " The jungle is not, properly 

 speaking, 'primeval forest,' forest, that is, untrodden by 

 the foot of man (such are in Ceylon of small extent and 

 rare occurrence) ; but it corresponds to our idea of such 

 a forest in that it consists of a dense and impenetrable 

 mass of mighty trees of all kinds, which have sprung 

 up without regularity or any interference from man, 

 and are surrounded and overgrown by a wilderness of 

 creeping and climbing plants, of ferns, orchids, and 

 other parasites, the interstices being so completely 

 filled up with a motley mass of smaller weeds that 

 it is quite impossible to disentangle the coil of ten- 

 drils so as to distinguish one species from the other. 

 My first attempt to penetrate such a jungle as this was 

 sufficient to convince me of the impossibility of the 

 undertaking except with the aid of axe and fire. A hard 

 hour's work brought me only a few steps into the thicket, 



• A pair of these little bullocks carry up about twenty bushels of rice to 

 the hills, and bring duun fiom fifty to sixty bushels of coffee to Cclombo. 

 (Sir). E. Tennem's" Nat. Hist, of Ceylon, f. 52) 



