326 [December, 1902.] 
IMPERIAL INSTITUTE JOURNAL. 
Vol. VIII. No. 96. 
step from an installation of turbines of a few thousand horse-power on a river steamer to the 
equipment of two costly vessels on which so much is depending as on the new Cunarders, 
with w'hat is, as yet, a comparatively new type of motor. Hence, it is likely that the great 
horse-power of these ships will be developed upon two or three shafts. If twin-screws are 
used, the proportions of propellers, shafting and engines would be enormous, since they 
would have to develop and carry probably not less than 25,000 to 27,000 horse-power each. 
There is absolutely no precedent for such sizes and weights, the largest twin engines at 
present being those of the Deutschland , which, when the boilers have been steaming freely, 
have developed as high as 38,000 horse-power, or 19,000 on each shaft. The new Kaiser 
Wilhelm II, it is true, is to have engines of 40,000 horse-power, or 20,000 upon each 
shaft, and in actual service they are likely to develop as much as 44,000, or, say, 22,000 on 
a single shaft. 
“ It is natural that the Cunard Company, in its endeavour to keep down the sizes of the 
separate engines, should turn to the triple-screw system of propulsion. By so doing each 
shaft would have to carry only 17,000 or 18,000 horse-power, or less than is now carried in 
the case of the Deutschland. The objection to triple screws is the very obvious one that the 
engine-room staff would have to be greater for three engines than for two. But, with this 
exception, it may be said that practically every other argument is favourable to the use of 
triple-screws. In the first place, judged from the all-important standpoint of safety of travel, 
there is less risk of total disablement in a triple- than in a twin-screw ship, If one engine is 
disabled only 33 per cent, of the power is lost, and the ship still has 66 per cent, with which 
to make port. The individual parts of the engine are much lighter, and hence it is easier to 
overhaul the engine in port or, in the case of a breakdown, to make repairs at sea. Although 
it might seem at first that more of the ship’s space will be taken up by three engine rooms 
than by two, the difference is not so great as might be supposed, inasmuch as the centre 
engine would be located on the centre line of the ship, astern of the wing propeller engines, 
and would occupy space in the least desirable portion of the ship from the standpoint of 
passenger accommodation. Admiral Melville, Chief of the Bureau of Steam Engineering of 
the U.S. Navy, is a strong advocate of the use of triple-screws, not merely for the navy, but 
for the large transatlantic steamships. Speaking on the important question of economy, he has 
shown that in the case of the fast commerce-destroyers, Minneapolis and Columbia, which 
are fitted with triple-screws, there was a very decided economy realised by their use. More- 
over, it is a significant fact that the French naval architects, who are among the best, if not 
the best in the world, and who are considered to have gone more deeply and thoroughly 
into the question of triple-screw propulsion than any other naval architects, appear to have 
adopted the triple-screw exclusively for all large ships of the navy. They claim that, quite 
apart from their obvious military advantages, triple-screws show a very decided economy 
over twin-screws. There is one other question which should be carefully considered in 
adopting twin-screw propulsion for transatlantic ships, and that is the question of vibration, 
which has so much to do with the comfort of passengers. It is a well-known fact that in 
the largest high-speed passenger vessels vibration is one of the most serious sources of dis- 
comfort. The effect of triple-screw propulsion in respect to vibration is a question which 
should receive a most thorough investigation. 
“ While speaking of vibration, one cannot but call to mind that the steam turbine, because 
of the absence of reciprocating parts, that is to say, of more or less unbalanced parts, is the 
ideal motor for passenger service. There is no question that the first transatlantic steamship 
that is fitted with a successful steam turbine will have a great advantage in this respect over 
high-powered boats driven by reciprocating engines. Broadly considered, it must be 
admitted that the success which has attended the installation of turbine units of great horse- 
power in electrical plants foreshadows the day when the steam turbine will be exclusively 
used in transatlantic travel. We cannot but think that the Cunard Company should give a 
most exhaustive study of the existing high-powered turbine plants before they decide that 
there is any inherent quality of the turbine which renders it unsuitable for use in tandem on 
the shaft of a transatlantic liner. Already turbines of 7,000 horse-power are under contract 
for electric railway plants. If they can be built in 7 >° 00 horse-power, they can surely be 
built successfully in 9,000 horse-power units, and two such turbines on each of the three 
shafts of the Cunard boats would give the desired maximum horse-power and something over. 
In an accompanying editorial and in the current Supplement will be found most powerful 
arguments on the score of economy of cost, weight and space, in favour of the steam turbine, 
and every one of these arguments applies with just as much force to the engine room of a 
transatlantic liner as it does to the power station of an electric railway company.” 

THE RIPENING OF CHEESE IN COLD STORAGE. 
The manufacture of cheese is one of the most important industries in Canada. Its 
extent may be illustrated by the figures showing the value of the supplies sent to the English 
market, which takes about nine-tenths of the total exports. Last year, 1901, the value of 
the imports of Canadian cheese into the United Kingdom was ^3,697,660 out of a total of 
^6,227,135 — the value of our imports from every source. That is, sixty per cent, of our 
imports of cheese were derived from Canada, and this proportion is increasing. The trade 
returns for the first ten months of this year show that Canada has so far contributed over 
65 per cent, of our imports of cheese. That Canadian cheese is so greatly in demand in our 
markets is, of course, due to its superior quality and its low price. Great credit is due to the 
Canadian Government for the attention it bestows on the industry, and the efforts which are 
made by the Dominion and Provincial Departments of Agriculture to ascertain by means of 
investigation and experiment where improvements in manufacture and preparation for market 
may be possible. 
The problem of ripening cheese in cold-storage is an important one and has been worked 
at both in the United States and in Canada. The latest information on the subject comes 
from the latter country, where Professors H. H. Dean, F. C. Harrison, and R. Harcourt, of 
the Ontario Agricultural College, have been occupied in experimental investigations bearing 
upon the matter. The Bulletin containing their report, which is published by the Ontario 
Department of Agriculture, Toronto, states that since the British market demanded a 
“fatter” cheese, or a cheese with softer body and texture, Canadian cheesemakers have 
been endeavouring to meet the demand, but have found some difficulty in doing so, from the 
fact that the average ripening (or curing) room at the factory is not adapted to holding such 
cheese for any length of time. In hot weather the temperature rises in the ripening-room 
with the rise of temperature outside. As a consequence, the cheeses “ go off” in flavour, 
and in many cases develop a mealy texture. To overcome these difficulties, better constructed 
ripening-rooms and better means of cooling them have been advocated, and improvements in 
these directions have been made by a number of factories ; but the majority are not yet in a 
position to make cheese with softer body. The labour of bringing ice to the ripening-room 
and putting it into the ice-boxes makes this method very expensive. The sub-earth duct has 
given fairly good satisfaction as a means of cooling the air in a properly insulated room ; but 
it does not maintain the temperature much below 65 deg. to 70 deg. F. Recently a move- 
ment has arisen in favour of central, or consolidated, cold-storage ripening (curing) stations. 
This plan has at least two circumstances to recommend it : — (1) it keeps the cheese safe from 
the effects of heat ; (2) it enables buyers to do their work at very much less expense for 
inspecting the cheese. The disadvantages are : — (1) the expense of operating such stations ; 
(2) the expense of shipping to them ; and (3) the fact that, under such a system, the cheeses 
are to some extent out or the hands ot the salesmen — though there is no reason why one 
saleman should not act for several factories, instead of each factory having a salesman as at 
present. Co-operation and consolidation should be the watchwords of modern dairy enter- 
prises. Too many small, poorly-equipped factories, which compete with one another for the 
small amount of milk in the locality, are a great injury to the Canadian cheese trade. The 
nature of the experiments, which are being repeated and extended this season, will be 
sufficiently understood by a glance at the conclusions so far arrived at. It has been found 
that an ice cold-storage chamber may be maintained at a temperature of about 40 deg. 
without moving the ice, if the building is well insulated. This high proportion of moisture 
in the cold-storage, amounting to 91 ‘6 per cent., provided favourable conditions for the 
growth of mould, hut this was no greater on the cheese in the refrigerator than on that in the 
ordinary ripening room ; in both places the mould was kept in check by using a solution of 
formalin through a hand spray-pump. The saving of loss in weight, by ripening at an 
average temperature of 37‘8 deg. for the season, was upwards of 2 per cent, on cheeses 
weighing about 30 lb. each ; in a large factory this is an important item, and would alone 
meet the cost of cold-storage for cheese in hot weather. The quality of the cheeses was 
found to depend upon the order, as regards time, in which they were placed in the cold- 
storage, those put in directly from the hoops ranking first. An increased yield representing 
at least 1 lb. of cheese per 1,000 lb. (equal to 100 gallons) of milk may be expected as a 
result of modifying the method of manufacture and ripening at a lower temperature than has 
been usually supposed necessary. The assertion that cheese kept in cold-storage for any 
length of time will quickly spoil when exposed to an ordinary temperature was not 
corroborated, but further experiments are in progress on this point. A cheese transferred 
from the hoop into a dry box and placed in cold storage, without any turning, ripened satis- 
factorily, though with a large amount of mould. A cheese put into a box, after ripening in 
the ordinary room for a week, gave similar results. Undesirable bacteria, such as are found 
in cheese, seem unable to grow at a temperature of 38 degrees, and consequently bad flavours 
in cheese, caused by bacteria, do not increase in cold-storage. The long life of lactic acid 
bacteria seems to have an important bearing on the question of ripening, in checking the 
development of bacteria which produce bad or undesirable flavours. The temperature at 
which cheese will cure best has yet to be ascertained. 
■ 
DOMINICA. 
In a new bi-monthly magazine entitled West India, devoted to the social and 
economic questions of the West Indies, the Flon. Francis Watts has written an interesting 
article on the Leeward Islands, the long chain extending from the Virgin Islands in the 
north to Dominica in the south. After a brief historical account of the group, a description 
is given of the various islands and their agricultural resources. Of Dominica, the Hon. 
Francis Watts writes as follows : — 
Dominica, the largest and most southerly of the Leeward Islands, is the one which at 
the present moment is attracting most attention. From its extremely mountainous character 
it was never cultivated in sugar cane to the same extent as its neighbours, and when the 
price of sugar fell it was in Dominica that the depression was felt with the greatest keenness. 
This led to an extension of the lime industry, which has long been established in this island. 
With the development of limes, cacao soon attracted attention, and both these industries 
have made rapid and substantial progress within the last few years. 
This island from the coast presents a rugged and unpromising exterior, but the interior 
is full of fine fertile valleys, along which flow rivers and mountain torrents in great number. 
This abundance of water, due to a heavy rainfall, in a tropical country means great fertility, 
hence these valleys, where not already cleared for cultivation, are filled with luxuriant forests, 
and, where cleared, with flourishing plantations of limes and cacao. Vast tracts of land are 
as yet scarcely explored ; their exploration and subsequent cultivation are being facilitated 
by a series of new roads now in progress, which, when completed, will afford a future full of 
enterprise and promise. 
The old roads of Dominica were few and bad, so that internal transport was difficult ; 
this delayed progress greatly, for although produce might be grown in great diversity, the 
getting of it to market was difficult or impossible, hence most of the older estates were 
within easy reach of the sea, which thus served as the great high road, a high road which on 
the windward coast is often unavailable, on account of the heavy breakers which are driven 
upon that shore by the steady trade-wind. Transportation is now being greatly facilitated 
by the introduction of a well-built coasting steamer touching at all available places on both 
the leeward and windward coasts. 
These improved means of communication by land and sea encourage the development 
of the country ; indications are abundant that new enterprises are rapidly following, and 
that the prosperity of the island is advancing in a rapid manner. 
Dominica appears to be capable of producing all those tropical products which require 
a good rainfall : limes, oranges, cacao, nutmegs, vanilla, bananas, coffee, rubber and others. 
The list might be extended to great length. 
The lime and cacao industries at present engage the greatest attention, though other 
industries are not neglected ; in course of time some of these may occupy a prominent place 
in the economy of the island. The lime industry is interesting from the diversity of its 
products. The fruit is exported in various forms ; the juice in two forms, either as expressed 
from the fruit in condition suitable for the preparation of refreshing beverages, or it is 
concentrated by evaporation in copper pans to a dark, thick liquid which serves as the raw 
material wherefrom citric acid is manufactured in Europe and America. Two kinds of 
essential oils are obtained from the rind of the fruit ; one is prepared by hand by rubbing the 
ripe fruit upon a saucer-shaped copper dish armed with many projecting spikes, which 
rupture the oil-sacs of the rind and cause the oil to flow down into the saucer where it is 
collected. Another form of oil is obtained by distillation from the juice ; the first stage of 
the evaporation above mentioned is conducted in a still ; the steam, being condensed, yields a 
considerable quantity of oil, which is readily separated from the water upon which it floats. 
The cacao industry of Dominica is receiving more attention, from which there is 
resulting a considerable increase in the quantity exported as well as great improvement 
in the quality. 
With the large amount of unoccupied and undeveloped land, with soil and climate 
capable of producing a wide range of tropical products, the prosperity of Dominica should 
yearly increase as the new areas are brought under cultivation. This is a condition which is 
particularly pleasing after the long period of depression which Dominica has endured and it 
is in refreshing contrast to the struggles, efforts, and economies of the sugar-producing 
islands. 

THE DISTRIBUTION OF OCEAN PASSENGER TRAFFIC. 
Some interesting compilations have just been made by the Customs authorities in 
New York about the distribution of passengers by the various ocean steamship lines. The 
returns show the number of passengers carried by each of these across the North Atlantic, 
and have a direct interest, in view of the fact that the belief is expressed in many quarters 
that the Shipping Trust will, in the future, make an effort to control passenger traffic. This, 
