BRIQUETTING TESTS. 47 
except that of the coal and binding material, is estimated to range from 25 to 50 cents per 
ton, varying with the local conditions. 
Where pitch is used as a binder, as is almost universally the case in each of these countries, 
its cost for a ton of briquettes may be said to range from 50 to 80 cents. How far this cost 
may be reduced by the use on a commercial scale of cheaper binders remains to be seen. 
The most favorable outlook for the development of this industry in the United States is 
in connection with the use of briquettes in locomotives and in domestic furnaces and stoves. 
It can hardly be expected that, at anything approximating existing prices, briquettes can 
be manufactured for successful use in the ordinary power-plant furnaces of the country. 
In connection with the use of briquettes for domestic purposes, the following advantages 
are claimed: 
1. That the briquettes burn with a higher efficiency and with less smoke, because they 
allow a better circulation of air and the combustion is more complete and more uniform. 
2. That the briquettes are cleaner, and that there is less waste in their use. 
3. That they burn with more flame (owing to the added combustible binding material) 
and at higher temperatures. 
4. That they occupy less space (by from 5 to 20 per cent) than does the lump coal. 
5. That they stand handling and exposure to weather better. 
6. That in their storage there is no risk of spontaneous combustion. 
A number of these advantages are also claimed for the use of briquettes in locomotives. 
SOME CHARACTERISTICS OF GOOD BRIQUETTES. 
In view of the great interest existing in the development of a briquetting industry in the 
United States at the present time and of the numerous efforts toward such development 
which are being put forth in different parts of the country, it may not be inopportune to 
introduce here a brief statement of some of the requisites of a briquette intended for general 
use: 
(1) The cost should be but little, if any, in excess of that of lump coal of the same kind as 
that from which the material in the briquette was derived. 
(2) The strength and binding material of the briquette must be such that it will (a) bear 
handling and railway transportation without serious loss from crumbling, (b) stand exposure 
to the weather without serious deterioration, and (c) retain its shape in the fire. 
(3) Its density should at least equal that of the lump coal from the same mine and, if 
practicable, should exceed it. It should not absorb more than about 3 per cent of water. 
(4) It should ignite readily and burn with a good, intense flame, and as nearly as possible 
without odor or smoke. 
(5) Its heating value should not be less than that of the best lump coal from the same 
mine. Naturally its heating value can not exceed that of this coal, except that if the bind- 
ing material used has a higher heat efficiency, this may slightly increase the heat efficiency 
of the briquette, and the more complete combustion which is claimed for the briquette as 
compared with the natural coal may still further slightly increase its relative heat efficiency. 
(6) Its ash should not exceed that of the best lump coal from the same mine. Whenever 
the conditions are favorable, the percentage of ash should be reduced by washing the fine 
coal preliminary to its use in briquette manufacture. 
The sizes of briquettes will vary according to the purposes for which they are intended 
and with other local conditions. In general, it may be said that the larger the briquette the 
cheaper its manufacture. Some of the English briquettes shipped to South America weigh 
as much as 20 pounds each. The English briquettes exported from Swansea average about 
10 pounds each in weight. The briquettes commonly used on locomotives in France, Bel- 
gium, Germany, and other European countries range from about 3 to 10 pounds in weight. 
The larger briquettes are generally broken into pieces before being thrown into the furnace 
or fire box, and this always causes more or less waste, but the large size is adopted for 
original manufacture owing to the smaller cost and the convenience in handling. The 
