324 



THE TROPICAL AGRICULTURIST. 



[Nov. 2, 1885. 



estate. Size such as would slip tlown between 

 two rafters. Sciile of tliis sketch is about l-l'2th. 

 Best maiei'iiil, stout zinc. Parts A, IS and C 

 should \)i' well stitl'ened with a ring of g's round 

 iron. 



If the building be a two-storied one, and the 

 lowermost specially needs ventilation at some given 

 point, the cyUnder of this ventilator by being 

 l^rolonged through the upper room nnd floor would 

 accomplish it and be always under control need- 

 ing no power. 



I have lived in an old English house built two 

 and a-half centuries ago, and all the window panes 

 were cemented into stone mullions, and our sole 

 means of ventilation were back and front doors 

 and one of those ventilators over the well of the 

 staircase, and our atmospheric condition was lirst- 

 class. For tea-house purposes 1, 2, 3, or 4 of 

 them could be fixed and draught regulated by 

 ope -ling or closing any one or all at pleasure. 

 Most suitable roof, I think, would be zinc tiles 

 underlaid with Willesden paper. — Yours &c., 



TRY. 



[We are sorry we cannot reproduce the diagrams, 

 but a gentleman whose opinion we value writes 

 as follows. — Ei>.] 



DB.iR " OnsEHVEB," — The enclosed plan of ventil- 

 ator is of approved pattern, and works well in 

 suitable conditions. It is constructed on the prin- 

 ciple, that, with two tubes (or two sides of a divided 

 tube) foniiing two perpendicular conduits from the 

 outside to the inside of a heated room the cold 

 air will come down one, and the hot air go up 

 the other. The one admitting the cold air has no 

 advantage in being beside the. other or descend- 

 ing perpendicularly, so far as effectiveness is con- 

 cerned. It would be equally good at the bottom of 

 the room ; only the arrmii/i'iiwiit is more convenient, 

 as it roiiuires only one hole in the roof, and one 

 ventilator. 



Its conditions are, that the heat of the room be 

 considerably greater than that outside. If the 

 room and outside air be of the same temperature 

 no ventilation ensues. If outside air be 40 deg. 

 and inside (JO deg. there would be a considerable 

 current. If outside 30 deg. and inside (iO deg. a much 

 stronger one. If the room be not very hiriie a good- 

 sized ventilator will sutlice with a moderate current. 

 The conditions of the tea-house are different. The 

 room is large and ventilation is most needed when 

 the temperature outside is hottest, ;. e. when the 

 current force is least. Suppose inside temperature 

 100 deg. and outside 100 deg., there would he no 

 current at all. The air outside is rarely more than 

 SO deg., so with a u-ldc enomfn exit and entrance 

 ventilation could be effected ; the taller the per- 

 pendicular tube tlmt eari'ios off the heated air, the 

 Ktrouger the current ; the wider tl'.e tube, the move 

 hBatC'd uif will be carried oJt It U just another 

 form of )i cliiiiinej-, turnac^, nsid furnace-door, A 

 high wid" (jhimne.V afordi* Hcope fof a lai'jie current 

 bi uil'i If !<■ b<: highly hoated thu air yoi-s up 

 ijiiickl.V.. If the dooi- allowing all' to tht' fiti'na'jO is 

 bptmfed, a gi'ei.t delil of uir will jiasii, 



Tij have a good current in thi.s countl-y, a tall, wida 

 fiA^ is rc(|uired, or a fan, A plan for ventilating a tea 

 utoi-l wotild have to be made to suit the arrange- 

 menif) Kf the stove. Give me plans &q. and I would 

 furnish one for tl'lah— Voiivs fvu1y, 15. 



/'. ,s'. — I see the write! of tliis \\m Hot under- 

 stood the principle on wiiich his ventilator 

 works. In his sketch he places arrows showing 

 air currents going out at both sides of the 

 dividend tube. The only advantage of the di- 

 vision is to make two passages out of one hole in 

 t)ie voof, so that cold air may enter byone 



and hot air escape by the other. I see no use 

 for your incurving the expense of engraving it, as 

 it is the ordinaiy ventilator in use. OX course 

 it either the back or front door of the house 

 described were opened, the hot air would go out 

 at both holes, the cold air entering by the door ; 

 but in that case of course the division of the 

 tube is no advantage. .J. B. 



BUC4,— NOTHING BUT BUG. 



Dk.iiII Sik, — I am glad to see that the publish- 

 ing of Dr. Gardner's Eepovt on Coffee "Bug" has 

 attracted your " editorial " notice. You have had 

 many hints of late about the damage " black-bug " 

 was doing, but up to now you have shunned the 

 subject as if it was a Gould-created scandal.* I trust, 

 that, now you have taken tbe matter up, you will 

 worry away at it as if it was a "railway extension 

 to Uva." Y'our offstart, however, is not encour- 

 aging, and I trust you will see the error of your 

 ways, like Macbride, and mend them. 



I have just re-read your pavagvaph to make 

 sure of what you have said, and really the article 

 is so unlike anything you put forward usually, that 

 I fear you must have been very busy when you 

 wrote it. 



You begin the article by saying "Dr. Gardner's 

 report on coffee ' bug ' first saw the light in 184k when 

 it was fully discussed in the Ubscrrer." Will you 

 please say how many of the present generation of 

 planters this discussion enlightened ? What we do 

 know is that it was bavven of any good vesult.f 

 Y'ou go on to say:. "It (the report) is of historical 

 and personal rather than of practical or scienlific 

 interest. In fact, it is so far behind, in its scientific 

 portions, the level of the knowledge of the present 

 day, that it would probably be treated as absurd 

 and childish by advanced scientists." So far I 

 entirely agree with you. Y'ou then quote a 

 passage from the report itself to the ett'ect that 

 "black-bug" must wear itself out; but conclude 

 your article by saying "and there the discussion of 

 ' bug,' like that of leaf-disea.se, must, we fear, 

 rest for Hie present." Rest for the present : I repeat 

 your closing words with emphasis, and ask, is the 

 Obsereer going to change its motto of Fiat Justitia 

 to lehiihodl Here is a scourge sweeping over the 

 land ruining all it touches. W'e don't know any- 

 thing about it, beyond the great d;unage it does. 

 We appeal to Government, who tell us a Dr. Gard. 

 ner wrote a report upon it 40 years ago. This 

 paper is got and handed to the conductors of tha 

 "press" for public enlightenment. The Observer in 

 noticing the vepovt calls it " absuvd and childish " 

 but fini-shes olf by saying " here the matter must 

 rent fur the present." Perhaps 40 years ago when the 

 subject wu , last discussed in the Db/erver this 

 conclusion was come to, and perhap.s thin may 

 be vepe.ttPd 40 yeni'i. hence, when th? BUbjecl 

 again ronien up fo!' discUiiijioni I always uiider- 

 fitooi! (he editors of thti obscrrnr took up a 

 matter of this* kind like an Ivishlnan did his 

 " isliilldlah," and Vapped evei'.vbody over the hc^ds 

 till they found out " who hit nie, father." 



I have just )iai!sed tf) light my cheroot, and seeing 

 how much and what I have written, I tremble, 

 and I must conclude by honing you won't be hard 

 on me. But before closing let me earnestly entreat 

 you to take this matter up, and never stop, till 



• We have repeatedly noticed it as a very old topic 

 on which there wasuothing new nor profitable lo be 

 Slid! — Eu. 



t Quits so, and why reprint the paper or discussion ? 

 -El'. 



