PROCURATOR 



6348 



PRODUCER-GAS 



Procurator (Lat. procurare, to 

 take charge of). An authorised 

 agent, especially one who conducts 

 legal business for another, and is 

 his accredited representative. In 

 Rome under the empire, the title 

 was held by governors of pro- 

 vinces, and also by the officer, cor- 

 responding to the modern collector, 

 who had the management of the 

 imperial revenues in a province. 

 Procurator is the technical term 

 for an attorney to conduct an ac- 

 tion by law, and in Scotland is the 

 usual designation of the legal re- 

 presentative of a litigant in the in- 

 ferior courts. The faculty of pro- 

 curators in Glasgow was incor- 

 porated by charter in 1796, sup- 

 plemented by a charter in 1897. 

 It fixes the professional fees of 

 procurators and undertakes the 

 auditing of their accounts. 



Procurator-fiscal. In Scot- 

 tish law, title of the public pro- 

 secutor -in the sheriff courts. He 

 is the sheriff's chief executive 

 officer for his particular district, 

 makes investigation of criminal 

 charges, performs a coroner's 

 duties by inquiring into causes of 

 suspicious deaths, prosecutes cases 

 indicted before the supreme court 

 of judiciary, and is responsible to 

 the sheriff and the lord advocate. 

 He carries out also those duties 

 which in England come within the 

 scope of the grand jury. He can 

 order the arrest of anyone, and 

 no action for wrongful arrest lies 

 against him unless malice can be 

 proved. Generally an enrolled law 

 agent, his appointment is made by 

 the lord advocate. 



Procyon OR THE LESSER Deo 

 STAR. One of the bright stars 

 situated in the constellation of 

 Canis minor. The star is remark- 

 able for being one of the nearest 

 stars to the earth, having a paral- 

 lax of - 32", and for its proper 

 motion. It is approaching the sun 

 at the rate of nearly 200 m. a 

 minute. In 1896 it was dis- 

 covered to be a double star. 



Prodicus (c. 480-400 B. c. ). Greek 

 sophist. A native of lulis in the island 

 of Ceos, he early came to Athens, 

 where his rhetorical gifts gained 

 him the friendship of all the dis- 

 tinguished men of his time. One of 

 his speeches contains the well- 

 known apologue of the Choice of 

 Hercules, of which an abstract is 

 preserved in the Memorabilia of 

 Xenophon. Hercules is represented 

 at the parting of the ways, where 

 he has to choose between Virtue 

 and Vice, who plead their cause in 

 the form of two women. 



Producer-Gas. Gas produced 

 in a furnace provided with means 

 for admitting fuel at the top with- 

 out allowing gas to escape. The 



Producer-Gas. 



fuel is kept aglow by passing air 

 through it as well as steam, the 

 combustion of the oxygen from 

 the air supplying sufficient heat to 

 offset the cooling effect of the dis- 

 sociation of the steam. At the 

 bottom of the furnace complete 

 combustion takes 

 place, and carbon 

 dioxide is formed. 

 As this gas rises 

 through the fuel 

 above which its 

 formation keeps at 

 a bright red heat 

 it is reduced to 

 carbon monoxide. 

 At the top of the 

 furnace the carbon 

 monoxide mixes 

 with the free hy- 

 drogen from the 

 steam and any 

 volatile gases 

 driven off from the 

 fuel before it be- 

 cameincandescent. 

 Producer-gas of this class is necess- 

 arily poorer in hydrogen than water- 

 gas, and contains, also, a large pro- 

 portion of nitrogen from the air. Its 

 calorific value is, therefore, low as 

 compared with that of coal-gas, 

 but this fact is more than counter- 

 balanced by the difference hi cost. 

 Its introduction, by J. E. Dowson, 

 in 1878, has had great effect on 

 the development of gas engines and 

 gas furnaces. 



Where producer-gas is required 

 in comparatively small quantities 

 for engines, a compact form of 

 producer is employed, and the air 

 and steam are sucked through the 

 fuel by the movements of the en- 

 gine's pistons. In other words, in- 

 ducted draught is substituted for 

 forced draught. Above is a dia- 

 grammatical representation of a 

 suction gas-producer, as this form 

 of apparatus is called, the gas 

 being known as suction gas. 



G is the generator with a feeder 

 at the top, and a water-sealed ash- 

 pit at the bottom. Round the top 

 runs a closed annular cast-iron 

 trough which acts as boiler. The 

 boiler communicates with the ash- 

 pit by pipe C, whi/h has a branch, 

 F, running to a hand-driven venti- 

 lating fan. Pipe H connects the 

 furnace with the dust-catcher, D. 

 To start the apparatus, a fire is 

 lighted in G and blown up by the 

 fan, cocks a and c having been 

 closed, and cocks b and d opened. 

 In about ten minutes good gas is 

 being produced, so cock d is shut 

 and c is opened. The gas now 

 passes through the system to an 

 auxiliary vent near the engine, 

 clearing out any stale gases. Blow- 

 ing is continued for a short time 

 after the engine has been started 



up, and a can then be opened and 

 6 shut. Air drawn in at A by the 

 suction of the engine passes over 

 the surface of the water hi B, and 

 absorbs moisture before traversing 

 C to the ash-pit. The gas formed 

 in the producer is sucked into the 



Sectional diagram of a suction gas- 

 producer. See text 



dust-catcher, where the heavier 

 dust is deposited in a water-sealed 

 pit. The finer dust is removed in 

 the scrubber while passing up 

 through coke, kept wet by water 

 sprayed on it from the top. The 

 gas then goes to the engine. 



Blast furnaces give off a type of 

 gas known as blast-furnace gas. 

 The gas is very poor in hydrogen 

 (7 p.c. ), and fairly rich in carbon 

 monoxide (23 p.c. ), containing also 

 9 p.c. of carbon dioxide. Though 

 the poorest of all producer-gases, it 

 is produced in such vast quantities 

 in the ordinary course of iron- 

 smelting that the furnaces of 

 Great Britain alone give off 

 sufficient to develop 4,000,000 h.p. 

 continuously. It has long been em- 

 ployed in the stoves which heat 

 the air blast, and for running the 

 boilers supplying steam to blow- 

 ing engines, though dust and car- 

 bonic dioxide render it somewhat 

 inefficient for the latter purpose. 

 In 1894 B. H. Thwaite discovered 

 that, if thoroughly freed of dust, 

 it is a good fuel for gas engines, and 

 it is now used on a large scale for 

 driving blowers and generating 

 electric power. 



The Mond process of gas-making 

 is very economical because it uses 

 the regenerative principle of heat- 

 ing, and can use small slack and 

 other waste fuel of very low value. 

 In the Mond process ammonia is 

 recovered in the form of sulphate of 

 ammonia, and the sale of this as 

 artificial manure goes a long way 

 towards paying all working ex- 

 penses. The air supplied to the 

 furnace is heated and moistened by 

 passing through a heating tower, hi 

 which it comes into contact with 

 water that has been pumped from 



