Oct. i, 1894.J 
THE TROPICAL AGRICULTURIST. 
235 
Their value for herbarium work is undoubted, a fact 
of which one is continually reminded by the absence 
of auy enumeration for some countries, and the 
unfortunate incompleteness of most of those which 
hivabeen Bet on foot. New Zealaud aud Auetnlta 
are well provided for, although the unflagging zeal 
of Baron Ferdinand von Muel er and his many helpers 
bas alreadv added bo much to oar knowledge that the 
" Fiora Austriliensis" is by no rruans up to date. 
Africa, both South and Trop oa', is less fortunate, the 
'■ F.ora UapensU" remaining whee it was at the death 
of Harvey m 1666, and the " Fieri o Tropical Africa,' 
although now onco more iu progress, hav.uj come to a 
standstill in 1877 Toanks ti the tnergyo! S r Joseph 
Hooker, we are witbiu reasonable distance of the 
completi n of the " Flora of British India"; ai.d the 
useful " Index Flo :e Sinensis," although not a de- 
scriptive flora in the sense of tho3e mentioned, is pro- 
cee'liog steadily. But wegr.atiy nee. I floras for the 
South Ameri an continent ; and Air. Hemsley s band- 
eorne Botany of the "Biologia Centrah Americana 
can hardly be con-idered exhaustive f)r the r g;oa of 
which it treats. To take a much more hmitea ar<.a, 
we have uo compendium for Madagascar, aud our 
knowledge of its wonderful flort has to be gleaned 
from a Urge number of sea ttre J paper-*. 
The existing floras, however, do not contain in aDy 
great degree des:r.ptions drawn from living nmt« r ' al 5 
and it is fortunate that the small aiei to which Vr. 
Trimen is restricted h is enabled him to treat hia 
plan's in this raMonal manner. It is to be regretted 
that his aims will be to some extent frustrated by the 
unneoesaarily bulky form whioh his " Uaudbo >k has 
assumed. The two volumes already issued conta n 
between seven and eight hundred pages, and at least 
as many more mutt be occupied by the remainder ot 
the work. The paper employed is much too tnica>, 
and by a different arrangement of type considerable 
savin" of space might have been effected, without 
mater ally detraoiing from the appearance of t.e 
volumes. It mav well be, however, that when the 
work is completed, Dr. Trimen will is-uo an abridge- 
ment for use in the field, which wou'.d oooupy t> the 
present handbook the position which Mr. Hay wards 
" Botanist's Pocket-book" holds with regard to our 
larger British manual". 
A word must be said in praise of ihe excel eut quarto 
plates whioh accompany the "Handbook.'' Thy are 
selected from a series of several thousand drawings, 
begun in 1823, when Mr. Moon was Director ot the 
Gardens, and preserved in the library. These are 
entirely the work of three members of one family. 
Hirmanis deAlwis, who has just died at a very ad- 
v meed age, held the post of draughtsman to the Gardens 
for thirty-eight years, and was sucoeedel by his sou*, 
one of whom has held the post for twenty-seven 3 ears. 
Most of the drawings here reproduced are his work. 
-Zature, Aug. 2. JAMBS BRITTEN. 
SISAL CULTURE , OR " THE ROMANCE OF 
A GOVERNORSHIP." 
"Old Colonist" sends the following letter to the 
Aberdeen Free Press ; but he Beems to forget that 
a great falling-off in the value of sisal fibre, as in 
that t£ all fibres, has taken place of late :-- 
Sir, Will you permit mo to supplement your in- 
to restii g article of yesterday on "The Romance of a 
Goveruorsh p" by a few notes on sisal culture? 
1 have not seen the article iu the Pall Mall U<r.ettc 
nnd would be sorry to fpoil a gool story, bat it strikus 
mo forcibly tint the discovery— if discovery it be— 
in due to S r Henry Blake, the previous Governor 
of the B»lmmae. Sir Ambrose Shea's "achievement" 
simply consists in loyally and enthusiastically fo los- 
ing up the Unas laid down by his predecessor. 
B.foro Sir Henry Bake's time, sisal hid only b.eu 
known in the Bahamas as a troublesome weed. What 
the Bathurst burr is to the Australian, the ageratuua 
to the Ceylon planter, the sisal plant was to the 
Bahamiau. From time to time vigorous efforts wero 
mude to eradicate tU nuisance, bat without success. 
The tenacity of the plant was something astounding— 
The more you tried to pull it out, 
The more it stuci the faster. 
The poor islauders gave it up in despair as an irre- 
roedia- Is, ir.emovable pest; and it is not surprising 
that, when first told of the fortune* that might be 
made out ot the dtspised weed, the information was 
received with iuondulity. 
The best variety of sisal is, however, the agave 
rigi le, var. sisnlaLa, plants of which were imported 
hy Sir Henry Blake an 1 fieely distributed in the 
Bahamas, when the va ue ot the fibre and importance 
of the industry was soon established. The ajave 
rigida grows wild in several parts of South America. 
I touna it abounding on many of the poor, dry, 
gravelly slopes of the Peruvian Andes. There is 
another plaut which yields a large quantity of similar 
fibre— fourcroja gigantea : but tbe quantity only 
amounts to 2 or 3 per cent., whereas the a^ave rigida 
gives 4 per cenfy equal to ha f a ton of merchantable 
fibre per acre worth, say, £50 per ton 
As to suitable lan I, there is any amount of this 
beyond the limits of the Bahamas. MaDy millions 
cf acres seem fit for little else, and ougho to be had 
for the asking, in bo.h West and East Indies, Aus- 
tral a, anl New Guiiei. Auy poor, r.clry, gravelly 
sol will answer, and the poorer the soil the better 
the fibre. Rich, moist land must be avoided, as, 
thoiiKh producing abundance of leaf, the fiora is 
inferior, albeit the sisal p ant tias the property of 
enriching rathr than impoverishing the soil it grows 
iD, as if iutendtd by Providence to prepare the way 
for other plants. 
The Colonial Governments have inde id, more than 
enough of this kind of soil to spare in the tropics; 
and our neighbours in Dundee, with their fatling 
jute induptry might da worse than turn their atteu- 
t on to sisal.— I am, etc., A. S. 
July 27th 1894. 
* 
STEAM BOILER EXPLOSIONS i 
THEIR CAUSE AND SOME SUGOESIIONS 
FOll THEIR PREVENTION. 
Tnere still remains iu coouectiou wi h hot-water 
work a subject which demands more delailed discussion 
than we have yet given it, for tLe very numerous and 
faial accidents of high-pressure boi ers, duriig severe 
frostP, seem to me to call for seme more light to be 
thrown on the subject. There is surely n.ej ot it when 
the only suggestion that an expeit of many years' 
expern nee could give was that peopl" should either not 
1 ght their ki chen fires during frosty weather, or else 
not let them out. So much for " experts." Much of 
the correspondence iu the press has also bejn of a 
nature to excite panic in the minds of ueers of hot- 
wa'er apparatus, aud calculated to prejudice people 
against their use. I will endeavour to show that there 
is no need for fear, and to prove that, properly fitted 
up, a dornsetic hot-water SjStem is as harmless as a 
domestic tea-kettle, and es little 1 kely to explode. . . . 
Though 1 have mentioned safety-valves, it must not be 
imagined that I consider them a perfect preventive. 
Far from it. Many of them, faulty in design ana make 
ara worse than useles 1 , for they ere te a feeliug of 
sscurity that is n t warranted, and is oftdn rudely 
d. spelled. For instance, a metal seated ground in 
valve, fixed up in the chimney as many are, wi.l get 
so firmly corroded ia time as to stand mo:epres;ure than 
even the boiler. It wi 1 be asked, " Iu what nay oon 
we ensura safety ? ' Iu the first p'ace, a large flow and 
return from boiler to cjlii.der is essential. A small 
p po q lickly furs up and quickly freezes. I advise lj- 
luch pipe for this, never less than 1 i-i ;ch. Have the 
cyliu icr as near the boiler us convenient. All pipes 
that are at all exposed to cold or draughts shoaid bo 
wrapped with fell cr cased with wood. Keip the ex- 
pansion pipe iusi !e the roof if posuble, as showu. 
Place a Kindell's Patent sifely-vatve on the cr.iwn of 
the oy Under, and lvt the tip on the boiler-emptying 
pipe also be Raudell's Pateut. No safety-valve 1, thoa 
needed ou the boiler. Do not omit (he stop top x 2. 
If these directions are carried out, nil will o»ve bum 
done by the fitter to ensure agood aud s de job,aud*ith 
intelligent and proper ruaungemeut accident is impos. 
eible.— From Cawtw New Technical Educator for Julvj 
