578 



NATURE 



[January 20, 19 16 



One of the best known automatic plants of this 

 type is the " Lister-Bruston." This plant has been 

 specially designed with the view of avoiding the 

 expense of the large batteries of accumulators ordin- 

 arily demanded by country-house lighting. The plant 

 consists of a dynamo driven by an internal-combustion 

 engine, but only a small set of accumulators is 

 needed. These accumulators are suflTicient to supply 

 three or four lamps without running the plant. 

 When, however, more lights are switched on, the 

 current demanded by the lamps causes a relay, or 

 automatic switch, to make contact, and the current 

 from the battery then passes to the dynamo, which 

 rotates for a few seconds as an electric motor, this 

 starting the engine. From this point onwards the 

 load is taken up by the engine and the dynamo, the 

 battery, however, being in parallel. By this means the 

 battery is kept charged, and has a steadying influence 

 upon the electric pressure. In the same way, when 



Finally, a few words may be said on the illumina- 

 tion of country houses in general. It is most essential 

 that the arrangement of the light's in the house should 

 be carefully studied. Cases are sometimes encoun- 

 tered where a large, and even an unnecessarily large, 

 plant has been installed, and yet the electricity avail- 

 able is not used to the best advantage. It is neces- 

 sary to consider the purpose of the lamps in each 

 room, and their positions should be selected with 

 care. Bare metal filaments are inconveniently bright, 

 and appropriate shades, softening the light and dis- 

 tributing it where it is chiefly needed, should be pro- 

 vided. By attending to these points it is often 

 possible to manage with a much smaller plant than 

 would otherwise be necessary. When electric light is 

 used, the consumer should be cautioned against undu' 

 economy in the matter of switches and plugs. It i- 

 best to arrange for full control of the lights, so as lo 

 avoid the waste of burning an unnecessary number ; 

 in most rooms a series of plug outlets round the walls 

 is useful in enabling portable lamps for special pur- 

 poses to be employed. 



The light should also be regarded as part of the 

 •^vstem of decoration of the room. An otherwisr 

 beautiful interior may be marred by an incongruous 

 and tasteless fitting ; on the other hand, appropriatt 

 shades and fixtures harmonising with the colour and 

 general style of decoration of the room add to its 

 effect. 



In converting old mansions to modern 

 illuminants, considerable skill and artistic 

 perception are often needed. Moreover, 

 the lighting of each particular room, hall, 

 dining-room, drawing-room, kitchen, bed- 

 room, etc., presents a different problem. 

 On the care with which this problem is 

 studied the whole utility of the generating 

 plant depends. 



Fig. I. — The Lister-Bruston electric generating plant. A petrol-driven engine drives a small 

 dynamo, supplemented hy a battery of small accumulators. By means of a special relay 

 switch (shown on the left) the battery starts up the engine when more than a few lamps 

 are put on. Similarly the switch is automatically released and the engine stops, when 

 the load falls below a certain value. The plant is thus automatic in action and only a 

 small battery is neieded. 



the lights are sufficiently reduced, the relay breaks 

 the circuit to the dynamo and the engine stops, the 

 few remaining lights being again run by the accumu- 

 lators. 



The plant is thus automatic in action, and is not 

 run when the load is very small. In the event of the 

 engine failing, the - load will be taken up by the 

 battery for several hours while the defect is put right. 

 One advantage of the system is that the charging 

 of the battery is automatically attended to, and the 

 danger of permanent damage owing to the cells 

 being allowed to remain uncharged for a long period 

 is avoided. The success of such an automatic system 

 demands an exceptionally robust type of cell, but it is 

 claimed that these cells can be left to themselves for 

 a long time without deteriorating. The firm also 

 undertakes to keep plant and battery in order for a 

 small annual sum. 



While this system is mainly intended for lighting 

 for country houses, it has also been applied to the 

 lighting of small villages. In this case, the usual 

 arrangement is to have several engines of varying 

 capacity, which are automatically switched into 

 circuit as the load increases and disconnected when 

 the demand is small. This ensures that the plant is 

 always working at full output and maximum 

 efficiency. 



NO. 2412, VOL. 96] 



Petrol-Air Gas for Heating. 

 In the article entitled " Modern Systems 

 of Independent Lighting and Heating " 

 in Nature of January 6, p. 522, the sec- 

 tion dealing with heating was necessarily 

 curtailed, and Mr. W. Willett directs our 

 attention to one point relating to his petrol- 

 air gas system on v.hich further explanation is need- 

 ful. It should be explained that either a rich or a poor 

 mixture of petrol and air can be oT)tained, the 

 richer mixture being preferred for heating. For 

 example, as stated, with the Willett plant a mixture of 

 2 per cent, of petrol is recommended for lighting ; but 

 the plant can be worked at either a 2 per cent, or a 

 6 per cent, mixture, according to the use for which 

 it is intended. In country laboratories a richer mixture 

 than 2 per cent, would be employed. Those selecting 

 a plant would naturally turn to the makers for fuller 

 particulars on this point. 



THE BONAPARTE FUND FOR 191 5. 



THE committee appointed by the Paris Academy of 

 Sciences to examine the requests for grants from 

 the Bonaparte Fund make the following proposals, 

 which have been confirmed by the academy : — 



3000 francs to Auguste Lameere, professor at th« 

 University of Brussels, to enable him to continue hi^ 

 researches at the Roscoff Zoological Station. 



4000 francs to Charles Le Morvan, assistant astro- 

 nomer at the Paris Observatory, for the publication of 

 a systematic and photographic map of the moon. 



2000 francs to Paul Vayssiere, for the continuation 



