302 



NATURE 



{July 24, 1879 



Prof. Bunsen, by the employment of different metals from 

 those hitherto tried, found that he could increase the 

 strength of the current, and M. Marcus, of Vienna, using 

 alloys instead of simple metals for the positive and nega- 

 tive element, reduced the cost, while increasing the power 

 of the battery. From a thermo-electric battery con- 

 structed on his principle, and also from a modified form, 

 devised by Wheatstone, a current sufficiently strong to 

 produce brilliant sparks, decompose water, &c., was ob- 

 tained. This was in 1865, and but little progress has, 

 until now, been made in this branch of science, with the 

 exception of the improved forms of thermo-pile devised 

 by Noe and by Messrs. C. and L. Wray, although the 

 utihsation of heat — -especially solar heat — for the pro- 

 duction oi electricity has long attracted the thoughts of 

 many experimenters. 



M. Clamond has for some time been at work upon the 

 subject, and has so far succeeded that his thermo-electric 

 battery has been employed since 1 875 in M. Goupil's fac- 

 tories. These batteries are formed of iron, as the electro- 

 positive element, and an alloy of antimony and zinc for the 

 negative ; they are soldered together and arranged in a 

 circular form, which can be built up as high as may be 

 desired. The junctions of the metals are heated in the 

 interior, but the electromotive force being proportional to 

 the difference of temperature between the two extremities 

 of each bar, it was necessary to make the bars long if a 

 strong current was desired, and then the results were less 

 satisfactory, owing to the increased internal resistance, 

 the melting of the metals where they were soldered, &-c. 



It is these hindrances to its extended use which M. 

 Clamond has sought to obviate in his latest form of 

 battery, which is composed of three distinct parts. The 

 collector consists of a number of pieces of cast-iron so 

 arranged that the heated air can circulate within them ; a 

 large surface is thus exposed to the heat, which the iron 

 collects and communicates to the couples. The difficscr 

 is the outside of the apparatus, and is made of sheets of 

 metal. The thcrmo-piU proper is placed between these 

 two, and is so arranged that the junctions of the metals 

 are alternately at the temperature of the collector and the 

 diffuser. Heat passes from the collector to the diffuser 

 along these couples, which have no great length. In 

 some forms which are very easily worked, a number of 

 these couples are made into a flexible chain of any desired 

 length, the extremities forming the poles of the battery. 

 These chains, insulated from the other parts of the 

 apparatus, can be united to each other by their free ends, 

 so that a variety of couplings and combinations may be 

 made. The model now in use for lighting a workshop in 

 Paris is about 2 J metres high, and i metre in diameter, 

 the exterior form being that of a polyhedron, to the sides 

 of which the thermo-electric chains are attached ; these 

 are composed of small cubes of zinc and antimony joined 

 together by plates of tin, to which they are soldered. 

 Each half of the apparatus has 30 chains of 100 couples 

 each, or 6,000 couples in all. To the outer surface of 

 these chains are fixed the sheets 'of copper which form 

 the diffuser or heat distributor. 



Another model, made for the recent exhibition at the 

 Albert Hall of the various systems of electric lighting, is 

 square and much smaller, though of the same power. 



Each half of the cylindrical battery can be made to 

 supply a powerful electric light, while the square one can 

 produce four lights of half the brilliancy. The electro- 

 motive force is, according to prolonged experiments, 31S 

 volts, about equal to 120 Bunsen cells, while the resist- 

 ance is 31 ohms. The large battery consumes only 9 or 

 10 kilogrammes of coke an hour, and the smaller one 

 even less, about 6J kilogrammes. Moreover, the large 

 exterior surface of the apparatus radiating its heat to the 

 air around adapts it admirably for use in heating, as well 

 as for lighting, and it can thus be made to serve the 

 double purpose of giving warmth and light. 



M. Sudrd has also designed his thermo-pile with a view 

 to obtaining one of small volume and having a low in- 

 ternal resistance ; the other peculiarities of his battery 

 consist in the manner in which one set of junctions are 

 heated while the other set are cooled. He has also 

 determined what is the best length for the bars forming 

 the couples, in order that the necessary difference of 

 temperature at the two extremities may be maintainec' 

 while yet making them as small as possible. This h. 

 finds should be from 10 to 30 millimetres, according to 

 the difference of temperature required. His manner of 

 soldering together the two different metals is also novel 

 and ingenious. In order that contact may be made with 

 the whole surface of the bar, he cuts the plate, formin 

 one metal, into the shape of a comb, twisting the teeth 0; 

 this comb together, thus retaining a large surface, which 

 yet has only a short length. The bars are fastened on 

 to these twisted parts and the uncut part of the plate is 

 coated with silicate of soda. The couples are formed in 

 a mould in which the plates are fi.xed, the melted alloy is 

 then run into the mould so that a block is formed of the 

 alloy and the plates, firmly united. These chains or 

 blocks are then placed between two plates, coated on one 

 side with enamel or other electrically insulating sub- 

 stance; several chains may thus be arranged side by 

 side, each chain being both calorically and electrically 

 insulated. The parts of the chain are electrically insu- 

 lated by the thickness of the plates, but heat can flow 

 across the couples. The chains are next placed between 

 a collector and a diffuser ; the collector is ribbed if the 

 source of heat be gas, in order to expose a greater surface. 

 The diffuser is also ribbed for the same reason when the 

 heat is merely allowed to radiate into the air. The whole 

 battery is so arranged that the collectors form the inside 

 of a circle within which the heated air is circulated. 



• BIOLOGICAL NOTES 



The Blood of the Lobster.— This liquid has been 

 recently examined by M. Fredericq (Belgian Academy's 

 Biillctiii, No. 4), whose researches on the octopus were 

 recently published. He finds in it as a rule two colouring 

 matters, one blue, an albuminoid, coagulated by alcohol 

 and heat, and apparently identical with the hccviocyaiiith 

 found in the blood of the octopus ; the other of rose 

 colour, and soluble in alcohol (not always present). The 

 former loses its blue colour in vacuo, and recovers it when 

 acted on by oxygen, and it contains copper. The blood 

 of the lobster is rose when it is reduced ; exposed to 

 oxygen it takes a special tint, blue with reflected light 

 (haemocyanine), brown with transmitted light (rose matter). 

 It coagulates spontaneously and therefore contains fibrine. 

 The blood of certain Gasteropoda {Arion, HcHx^ is also 

 found to contain hremocyanine, whereas M. Fredericq has 

 not found it in the Lamellibranchiata ( Unio,Anodonta). The 

 general conclusion is reached that in such different groups 

 of invertebrates as cephalopod and gasteropod molluscs, 

 Crustacea and annelids, as well as in vertebrates, respira- 

 tion is effected by means of metalliferous proteic sub- 

 stances (haemoglobin, haemocyanine, chlorocruorine) which 

 form in the respiratory organ (branchia, lung) less stable 

 oxygenated combinations. These latter are dissociated 

 in their passage through the tissues. In invertebrates, 

 the two great functions of the blood, respiration and 

 nutrition of tissues, belong both to the plasma, the cor- 

 puscles having a quite accessory importance. In th-e 

 blood of vertebrates there is, in this respect, a division of 

 physiological work ; the respiratory function devolves 

 upon the corpuscles, the nutritive function on the plasma. 



Annelids of the Virginian Coast. — Mr. H. E. 

 Webster has just published an account of the Annehda 

 Chastopoda which were collected in the summer months 

 of 1874 and 1876 by the zoological expeditions sent out 



