374 
FOREST AND STREAM. 
[May 12, 1^0. 
Clarette, yawl, designed by S. D. Small and built by the 
Neilson Co., at Baltimore, arrived at Boston on April 27 
after a very satisfactory trial trip from Baltimore. Her 
owner, Vice-Com. Waiter Burgess, Boston Y. C, was 
in charge, accompanied bv Messrs. W. E. Dickson, W. C. 
Lewis and W. Turner. The yacht is 38ft. 6in. over all, 
23ft. 9in. l.w.l., lift, breadth and 2ft. 6m. draft, with 
2,ooolbs. of lead keel; her sail area is 1,050 sq. ft. She 
will race either under yawl rig in the 21ft. cabin class 
of the M. Y. R. A. or under sloop rig in the 25ft. class. 
1^ 1^ 8^ 
Ellida, vawl, designed by C. H. Crane for his brother- 
in-law, Austin Fox Riggs, of New York, was launched 
at Piepgrass' Yard, City Island, on May 2. She is 48ft. 
over all, 30ft. l.w.L, lift, breadth and 7ft. draft, designed 
for cruising. The hull is strongly built, and Mr._ Piepgrass 
has turned out a very neat piece of workmanship, outside 
and below decks. The rig is peculiar, the mainsail being 
excessively high and narrow. 
^ ^ ^ 
Messrs. Fife & Son, of Fairlie, launched on April 24 the 
new 65-rater Khama, for Mr. Kenneth M. Clark. Khama, 
which is an out-and-out racer, is considerably finer in her 
overhangs than any previous Fairlie yacht, notably more 
so than Shamrock, and in her midship section she is not 
at all unlike Columbia. She appears shorter on the keel 
than Senta. and rather longer over all, with an easy-look- 
ing bilge and slight tumble-home. Khama' s entire fram- 
ing is of angle steel, well stayed and braced throughout. 
She is in charge of Archie Hogarth, and is expected to 
be ready in good time for the opening matches.— -The 
F'ield. 
* *E 
The second challenger for the Quincy cup is described 
as follows by the Beverly Times : 
Down at Bezanson's Yard, on Water street, the men 
are busily engaged on John S. Lawrence's new 21-footer, 
a challenger for the Quincy cup. 
The craft will sail under the colors of the Harvard Y. 
C. Like last year's defender, Hostess, and like Look- 
out, she is of the extreme Skow type into which strictly 
racing boats have developed under a simple waterline 
rule of measurement. The features of these boats are 
their extremely long and low overhangs, their great 
beam, their shallow hulls and the carrying of their floors 
well into the bilges. In actual sailing the result of such 
a model is that as the boat heels she increases her water- 
line length and decreases her beam until she is about rail 
down, when she is sailing on about half her actual beam. 
The increase in speed due to the lengthening and narrow- 
ing of the boat is something wonderful as compared with 
the speed when the boat is upright. . 
Mr. Lawrence's boat is from his own design, and is 
41ft. over all, 21ft. waterline, 13ft. breadth and Sin. draft. 
Her hull is 2ft. in depth. The deck plan shows but little 
narrowing of the breadth fore and aft from the extreme 
of 13ft. amidships, and the boat is loj^ft. broad at the bow 
and 12ft. at the stern. Her floor is flat and her topsides 
straight. The turn of the bilge connecting them is very 
sharp arid hard ; in fact, it is only made a turn instead of 
an angle for convenience in planking arid construction. 
The topsides carry their straightness clear to the bow, 
but flare somewhat toward the stern so as to give the 
water an easier passage aft. 
A novel feature of her design is that she will carry a 
leeboard on either side instead of the usual centerboard. 
The leeboards are pivoted to the sides of the boat and can 
be raised and lowered after the manner of a centerboard. 
Only one is used at a time, the leeward one, and the 
designer believes that leeway will be better prevented than 
by the use of the centerboard. The boards are about Sft- 
long by 2ft. wide. . 
The rudder is narroAv. deep and balanced, and is set 
well under the boat. A jib and mainsail rig will be cacjried 
that will contain about 1,300 sq. ft. of sail. ^ 
An essential feature that has kept pace with the model m 
the development of the Skow type has been that of light 
construction. The Lawrence boat is to be of extremely 
light build with canvas, but is to be strengthened and 
stiffened by five longitudinal trusses of light lattice work, 
and by several transverse trusses of the same style. 
The boat will be delivered to her owner in the latter 
part of May, and with Mr. Higginson's boat, which will 
be delivered about the same time, will be taken to Hull 
Bay and there tuned up for the races by constant practice 
sailing. 
J? J? , a £ 
The number of new boats to be added to the fleet of 
the Oregon Y. C. this year is large. Members are be- 
ginning to put their old boats in condition with caulking 
iron and paint brush. The-flag.ship Agnes will soon be 
ready to go into commission, and it is understood that 
Mr. Wolff's new racer will be launched very shortly. The 
two boats building under the supervision of Nelson 
Dodge are progressing rapidly, and will undoubtedly 
prove a source of much satisfaction to their owners. 
The large knockabout being built by Mr. Duthie is near- 
\ng completion, and will probably be launched by the 
middle of May. The sloops Windemuth and Curio are 
hauled out on the float, preparatory to receiving the 
.spring coat of paint. The opening regatta on Decora- 
lion Day, aside from the fact that the new flyers will 
compete for the first time, will present a beautiful sight 
for spectators, inasmuch as the entire fleet will have the 
bright, fre^h appearance due to a recent visit to the paint 
shop. It is the desire of the club to m.ake this first 
regatta a success in every way. The race will be sailed 
under the new rules, which do away with the antiquated 
sail tax and time allowance, and place each boat on its 
own merits with regard to sailing qualities. The one- 
gtm start will also be used, which will bring into play 
all the skippers' skill when jockeying for the weather 
berth before the signal. Under the new regulations the 
first boat of a certain class to cross the finish line is the 
winning boat in that class, a fact of interest to spectators, 
inasmuch as there will be no tedious waiting for the 
judges to figure out the time allowance.— Portland Tele- 
There are now on the ways at Poillon's Yard. South 
Brooklyn, two new yachts designed by Messfs. A. Car:" 
Smith Barbev, both being good examples of. modern 
design and durable construction. The larger, to be named 
Laurus, is a schooner, for Dr. J. C. Ayers, of Boston ; 68ft. 
over all, 46ft. l.w.l., 15ft. 6in. breadth and 7ft. draft of 
hull. She has a lead keel and a small centerboard, with a 
large cabin trunk to give the necessary head room. 
Though a sailing yacht in model, closely resernbling the 
one-design schooners Clorita and Uncas, she will have a 
Globe gasoline engine and a double-bladed screw working 
in a small aperture cut out of the sterhpost and rudder. 
The second yacht, Curlevy, was designed for Gilbert H. 
Wilson, of Wilson & Griffin, for the Great South Bay, the 
draft being limited to 2ft. 3in. She has 44ft. 6in. length 
over all, 30ft. l.w.L, 13ft. 2in. breadth, with sloop rig. She 
is fitted with a summer cabin which may be removed at 
will. The cockpit is quite large. Both of these boats have 
the overhangs formed by the carrying out of the diagonals 
on fair and natural lines. They are very substantially con- 
structed and yet are not excessively heavy. 
H »o »l 
Columbia II.. steam yacht, J. H. Ladew, arrived at 
New York on May i, after a winter cruise in the West 
Indies. She will refit for a voyage to Europe. 
§Hnoiiing. 
CANOEING NEWS NOTES. 
The canoeist is, as a rule, apt to be more or less of an 
amateur mechanic ; at the very least, his small and deli- 
cate craft requires certain attentions which cannot well be 
left to ordinary caretakers, but demand the personal 
attention of the owner. The atmosphere of a canoe club 
house is contagious and is apt to make fair mechanics of 
most of the active sailors, some not stopping short until 
they are able to build their own craft. To those who are 
beginning or who wish to perfect themselves further in 
amateur work, we can recommend the book entitled 
"Woodworking for Beginners," by Charles G. Wheeler, 
B. S,, just published by G. P. Putnam's Sons. This book 
is by far the simplest, plainest and most practical that we 
have yet found among amateur handbooks. The object 
of the writer is less to instruct in certain operations than 
to inculcate the leading principles and to induce the 
learner to depend on himself and to use his head as well as 
his hands. The ordinary tools and materials are very 
fully described and the specific instructions on various 
points are explicit and correct. Unlike many books on the 
subject, this one is evidently based upon a thorough 
understanding of the principles of joiner work and the 
use of woodworking tools, and though parts are sufficiently 
elementary and simple for the 3'oung novice, there is much 
in it that will be found of practical value to the average 
skilled mechanic. The direct instructions and descriptions 
include many articles, toys, furniture, small houses, models 
and boats. The book will be found equally useful to the 
man or bov who is forced to content himself with a plain 
table or small bench and a few tools, or to those more 
fortunate ones who possess a workroom and good working 
outfit and aspire to do really good work 
A. C A. Membership. 
Eastern Division— Roland Finley, Chas. A. Lakin and 
Harry L. Hastings, Fatassit C. C. 
Central Division— Dr. Chas. Van Bergen, Asheville, 
N. C. 
§ifi^ §^n^e mid §dtUr^* 
Modern Explosives** 
The subject of explosives is one which never fails to 
excite interest even under the most ordinary conditions, 
doubtless owing to the enormous potentiality of these 
substances, while at the present time more than usual 
attention is directed to them, it being scarcely possible to 
read a daily paper without finding some reference to the 
behavior of various modern explosives in the theater of 
war. , - , • 
Explosion may be defined as chemical action causing 
extremely rapid formation of a very great volume of 
highly expanded gas, this large volume of gas being gen- 
erally due to the direct liberation by chemical action and 
the further enormous expansion by the heat generated. 
Explosion itself may therefore be regarded as extremely 
rapid combustion, while the efi^ect is obtained by the 
enormous pressure produced owing to the products of 
combustion occupying probably many thousand times the 
volume of the original body. The effect of high temper- 
ature is seen in the well-known case of explosion of a 
mixture of hydrogen and oxygen, where if die original 
mixture and the products of explosion are each measured 
at the =iame temperature above the boiling point of water, 
a less volume of gas (water vapor) is actually found. The 
explosion can only have been produced by the enormous 
expansion of this vapor in the first place by the heat ot 
the reaction. Such an explosion, when carried out in a 
closed bomb, with the mixed gases under ordinary con- 
ditions of measurement, produces a pressure of about 
■40 pounds to the square ineh. A more practical illus- 
tration is seen with nitro-glycerine, which Nobel found 
yielded about 1,200 tim.es its own volum.e of gas calcu- 
lated at ordinary temperatures and pressures, while the 
heat liberated expands the gas to nearly eight times this 
volume. , 1 • X 
Clearly, then, a substance for use as an explosive must 
be capable of undergoing rapid decomposition or com- 
bination with the production of large volumes of gas, 
and further produce sufficient heat to greatly expand these 
gases- the ratio of the volume of gases at the moment of 
explosion to the volume of the original body largely de- 
termining the efficiency of the explosive. 
Explosives may be divided into two great classes — 
mechanical mixtures and chemical compounds. In the 
former the com-bustible substances are. intimately .mixed 
~*J'ier.t<Are delivered at th« T^don Institution on Feb. 13, by 
Mr.,'j."S; S. Brsm«r, . . '...i 
with some oxygen-supplying material, as in the case 
of gunpowder, where carbon and sulphur are intimately 
mixed with potassium nitrate, while gun-cotton and nitro- 
glycerine are examples of the latter class, where each 
molecule of the substance contains the necessary oxygen 
for the oxidation of the carbon and hydrogen present, the 
oxygen being in feeble combination with nitrogen. Many 
explosives are, however, mechanical mixtures of com- 
pounds which are themselves explosive — e. g., cordite, 
which is mainly composed of gun-cotton and nitro- 
glycerine. 
Two methods are in common use for bringing about 
explosions — ignition by heat, thus brining about ordinary 
but rapid combustion, molecule after molecule under- 
going decomposition; and detonation, where the effect is 
infinitely more rapid than in the first case — in fact, may 
be regarded as practicaly instantaneous. The result may 
be looked upon as brought about by an initial shock im- 
parted to the explosive by a substance — the detonating 
material — which is 'capable of starting decomposition in 
the adjacent layers of the explosive, thus causing a shock 
in the next layer, and so on with infinite rapidity. That 
the results are not entirely due to the mechanical energy 
of the liberated gas particles is shown by the fact that the 
most powerful explosive is not the most powerful de- 
tonator; neither is it entirely due to heat,_ since wet sub- 
stances undergo detonation. The probability is that the 
result is brought about by vibrations of particular veloc- 
ity which vary for different substances, the decomposi- 
tion being caused by the conversion of the mechanical 
force into heat in the explosive, thus bringing about a 
change in the atomic arrangement of the molecule. Ac- 
cording to Sir Frederick Abel's theory of detonation, the 
vibrations caused by the firing of the detonator are capa- 
ble of setting up similar vibrations in the explosive, thus 
determining its almost instantaneous decomposition. 
The most common and familiar of explosives is un- 
doubtedly gunpowder, and although for military pur- 
poses it has been largely superseded by smokeless pow- 
ders, yet it has played such an important part in the his- 
tory of the world during the last few centuries that apart 
from military uses it is even now of sufficient importance 
to demand more than a passing notice. 
Its origin, although somewhat obscure, was in all 
probability with the Chinese. Roger Bacon and Berthold 
Schwartz appear to have rediscovered it in the latter 
years of the thirteenth and earlier part of the fourteenth 
centuries. It was undoubtedly used at the battle of 
Crecy. The mixture then adopted appears to have con- 
sisted of equal parts of the three ingredients, sulphur, 
charcoal and niter; but some time later the proportions, 
even now taken for all ordinary purposes, were intro- 
duced, namely: 
Potassium nitrate ... 75 parts. 
Charcoal iS parts'. 
Sulphur 10 parts. 
Since gunpowder is a mechanical mixture, it is clear 
that the first aim of the maker must be to obtain perfect 
incorporation, and necessarily, in order to obtain this, 
the materials must be in a very finely divided state. 
Moreover, in order that uniformity of effect may be ob- 
tained, purity of the original substances, the percentage 
of moisture present, and the density of the finished pow- 
der are of importance. 
The weighed quantities of the ingredients are_ first 
mixed in gun metal or copper drums, having blades in the 
interior capable of working in the opposite direction^ to 
that in which the drum itself is traveling. After passiilg 
through a sieve, the mixture (green charge) is passed on 
to the incorporating mills, where it is thoroughly ground 
under heavy metal rollers, a small quantity of water being 
added to prevent dust and facilitating incorporation, and 
during this process the risk of explosion is greater possi- 
bly than at any other stage in the manufacture. There are 
usually six mills working in the same building, with par- 
titions between. Over the bed of each mill is a hori- 
zontal board, the "flash board," which is connected with 
a tank of water overhead, the arrangement being such 
that the upsetting of one tank discharges the contents of 
the other tanks on to the corresponding mill beds below, 
so that in the event of an accident the charge is drowned 
in each case. The "mill cake" is now broken down be- 
tween rollers, the "meal" produced being placed in strong 
oak boxes and subjected to hydraulic pressure, thus in- 
creasing its density and hardness, at the same time bring- 
ing the ingredients into more intimate contact. After 
once more breaking down the material (press cake), the 
powder only requires special treatment to adapt it for 
the various purposes for which it is intended. 
Within the last half century an enormous alteration has 
taken place in artillery, the old smooth-bore cannon, firing 
a round shot, having gradually given place to heavy rifled 
cannon, firing cyHndrical projectiles and requiring very 
large powder charges. This has naturally had its influ- 
ence on the powder used, and modifications have been in- 
troduced in two directions — first, alteration in the form of 
powder, and second, in the proportions of the ingredients. 
As the heavier guns were introduced, a large grain pow- 
der, which burned more slowly, was adopted, but further 
increase in the size of the guns led to the introduction of 
pebble powders, which in some cases consisted of cubes 
of over an inch side. Such cubes, having large available 
surface, evolved the usual gases in greater quantity at the 
start of the combustion than toward the finish, since the 
surface became gradually smaller, thus causing extra 
strain on the gun as the projectile was only just begin- 
ning to move. Gen. Rodman, an American officer, in- 
troduced prism powder to overcome this difficulty, the 
charges being built up of perforated hexagonal prisms, in 
which combustion started in the perforations, and pro- 
ceeding, exposed more surface, the prisms finally break- 
ing down into what was virtually a pebble powder. 
In order to secure still further control over the pres- 
sure, modifications in the proportions of the ingredients 
became necessary, the diminution of the sulphur and in- 
crease of the charcoal causing slower combustion, and 
moreover the use of charcoal prepared at a low tempera - 
ture giving the so-called "cocoa powders." 
The products of the combustion of powder and it.s 
manner of burning are largely influenced by the pressure, 
a property well illustrated by the failure of a red-hoi 
platinum, wire to ignite a mass of powder in. a vacuuni 
only a few grains actually in contact with the platmur.! 
undergoing combustion. The gaseous produces obtained 
