1018 



COFFEE TRADE. 



COFFER-DAM. 



1011 



cases of asthma, either alone or with tincture of opium, it has kept off 

 the paroxysm. Strong coffee is the best and safest means which can 

 be employed by unprofessional persons to obviate the effects of all 

 vegetable poisons which act upon the brain, and induce a fatal sleepi- 

 ness and torpor. It is much more proper than vinegar which should 

 never be given till all the poisonous substance has been removed from 

 the stomach. 



In some affections of the kidney and bladder, such as laxity and 

 debility of these organs, coffee is of much service; and it has been 

 stated by some writers that calculous complaints have diminished since 

 its more extensive use. 



Caffeina has not yet been used 'extensively in medicine, but Geiger 

 justly anticipates that a principle so rich in nitrogen will be found to 

 be an important medicinal agent. It is a powerful stimulant. 



A beautiful green, which is unchangeable, and resists the action of 

 acids, light, and moisture, may be precipitated from a decoction of 

 decayed coffee, by means of pure soda. [CAFEIO ACID.] 



COFFEE TRADE. Referring to the NATURAL HISTORY DIVISION 

 for an account of the botanical relations of the coffee-plant, and of the 

 mode of preparing the bean or berry for the market, we shall here 

 offer a few observations on the coffee-trade not simply in its buying 

 and selling, but also in relation to the apparatus for preparing it. 



Coffee beans should not be roasted long before they are ground, nor 

 long before they are to be made into a decoction ; the retention of the 

 aroma, and of all the good qualities in the coffee, depends on this. 

 About half an ounce of coffee powder should be used for every eight 

 ounces (half a pint) of water. In Britain the roasting is generally 

 carried too far. It was an endeavour to establish an improved mode 

 of roasting coffee that led to the death of Mr. Dakin, of St. Paul's 

 Churchyard, in 1848. His plan consisted in placing the coffee in a 

 cylinder lined with silver, and in enclosing this cylinder within a 

 cellular steam oven, or cylinder, patented by other parties. The heat 

 attained within the oven was very great, and the metal of the oven was 

 not sound enough to resist its action : an explosion ensued, with a 

 fatal result. The silver or silvered cylinder was an intended means of 

 retaining the fine qualities of the coffee, without acquiring any defec- 

 tive qualities during the roasting. 



Considerable ingenuity has been displayed in devising apparatus for 

 preparing coffee for the table. The ordinary coffee pot is the plainest 

 and simplest of all ; there is no contrivance for filtering the coffee. In 

 Dresden and other parts of Germany, a thick piece of flannel or some 

 other woven material, is laid in a funnel ; the ground coffee is placed 

 on the flannel ; and the boiling water filters through the coffee, the 

 flannel, and the funnel, to a vessel below carrying with it the flavour 

 of the coffee without the grounds or sediment. 



PlatoVs Automaton Coffee Pot has for its object to make coffee in 

 less time and in a better manner than by the ordinary method. The 

 machine consists of two parts. There is at the top a glass vase which 

 screws off and on by means of wooden handles, and is furnished with a 

 long narrow straight tube, resembling the pipe of a common funnel, 

 and reaching nearly to the bottom of a metallic urn placed beneath the 

 vwse. Boiling water is poured into the vase in quantity sufficient for 

 the coffee to be made ; and this is allowed to descend into the urn. The 

 ground coffee is then placed within the vase, on a small perforated 

 silver plate. A lamp containing spirit or naphtha is placed beneath 

 the urn ; and in a short time the peculiar action of the apparatus 

 developes itself. The steam formed on the surface of the water in the 

 urn forces, by its elasticity, the water up the tube into the glass vase ; 

 where it acts upon the coffee in the usual way for extracting the 

 qualities of the berry. When the coffee is so far prepared and is 

 required to be fined, the lamp is removed, the formation of steam 

 ceases, a partial vacuum is formed in the urn, and the external atmos- 

 phere, pressing on the open vase, presses or strains the coffee, first 

 through the grounds and then through the perforated silver plate ; so 

 that it trickles into the urn in the state of a pure bright decoction. It 

 is thus seen that the liquid makes two descents and one ascent between 

 the vase and the urn, during the process. In a cheaper form of the 

 apparatus, a common fire or a lamp is used instead of a spirit lamp. 



A coffee-pot of rather complicated structure was patented by Mr. 

 Andrews of Wolverhampton, in 1842. This coffee-pot had no less an 

 adjunct than a small forcing-pump, placed near the handle. The 

 boiling water was poured in the forcing-pump, while the ground 

 coffee was put in a perforated vessel in the middle of the coffee-pot ; 

 Mid the hot water, being forced by the pump, was made to saturate 

 the ground coffee in a way which (we presume) was supposed to 

 produce a result adequate to the costliness of the apparatus. 



Waller's Coffee Pot, patented in 1847, differs in many particulars 

 from all the others. A horizontal partition, perforated near the centre 

 with fine holes, divides the vessel into two equal chambers ; an open 

 pipe leads nearly from the top of the upper chamber to near the 

 bottom of the lower chamber ; and another pipe leads from the per- 

 forations some way down the lower chamber, with a tap or cock which 

 can be worked by a handle protruding through the side of the coffee- 

 pot. The requisite quantity of water, either hot or cold, is poured 

 into the upper chamber, and allowed to flow through the perforations 

 and small pipe into the lower chamber ; the ground coffee is placed on 

 the perforated plate ; the spout is closed with a cork or plug ; and the 

 vessel is placed on the fire. As the water becomes heated, the steam 



generated has no outlet upwards or sideways, and it therefore presses 

 on the water, and forces it up the long pipe, whence it falls into the 

 upper chamber, upon the ground coffee. When all the water is thus 

 forced up, the coffee-pot is removed from the fire, the vacuum in tho 

 lower chamber is condensed, the plug is removed from the spout, the 

 top of the short pipe is opened, and the water trickles through the 

 ground coffee and through the perforations into the lower vessel, 

 imbibing all the soluble and aromatic properties of the coffee as it 

 descends. 



Many other varieties of coffee apparatus have been invented within 

 the last few years ; but they need not be separately described here. 



Attention has been directed within the last few years to the pro- 

 perties of coffee leaves, as a substitute for the berry. It has been 

 ascertained, by a mercantile house at Singapore, that roasted coffee 

 leaves could be there sold at twopence per pound ; and in 1853 an 

 attempt was made to introduce this article into the English market- 

 hitherto without much success. An essence of coffee is made for 

 keeping ; it consists of a highly concentrated infusion, mixed to the 

 thickness of treacle with chicory and burnt sugar, and kept cool in 

 well corked bottles ; it is used to make coffee beverage quickly under 

 special circumstances, but it is not quite equal to fresh coffee. Coffee 

 syrup is the essence combined with sugar and milk, and greatly 

 evaporated; it becomes coffee paste, and then coffee candy, if the 

 evaporation be still further continued. 



Coffee is adulterated to an enormous extent, as sold in the retail 

 shops. Chemists have detected, mixed up with it hi various ways, the 

 following substances acorns, almonds, beans, beech-mast, beet-root, 

 chick peas, currant seeds, clu'cory, gooseberry seeds, holly berries, 

 lupins, rice, rye, sassafras, water flag seeds, and many others. The 

 chief among these adulterants is chicory, which is often mixed in 

 enormous quantity with cheap coffee. The best security against 

 adulteration is perhaps to purchase the coffee unground. 



We now present a few figures concerning the coffee trade. 



It has been estimated that the quantity of coffee annually exported 

 from the countries where it is grown cannot be less than 120,000 tons, 

 or 2,400,000 cwts. Nearly all the coffee now consumed in Europe is 

 the produce of trees propagated from a single seed, sent from Mocha to 

 Batavia in 1698 ; the progeny of this first plant was sent to the Went 

 Indies in 1718; and thus the great coffee plantations began. The 

 chief coffee growing countries are Ceylon, Brazil, Central America, 

 Cuba, Hayti, Java, British West Indies, Guiana, French West Indies, 

 Porto Rico, Sumatra, Isle of Bourbon, Manilla, and Mocha ; these arc 

 enumerated nearly in the order of their importance. England pur- 

 chases far less coffee than France, Germany, or the United States, in 

 which countries coffee drinking is more prevalent. Our total imports, 

 in certain years, were as follows : 



1845 50,000,000 Ibs. 



1850 51,000,000 



1865 64,000,000 



1858 81,000,000 



This list does not denote the quantity of coffee used in the United 

 Kingdom ; for a greatly-fluctuating proportion is every year re-ex- 

 ported. The quantity retained for home consumption varies from 

 35,000,000 to 40,000,000 Ibs. per annum. In 1844 the importations 

 from British possessions were about equal to those from foreign 

 possessions ; but since that year the former have more and more pre- 

 dominated ; until at length in 1S58 the ratio was 51 millions of pounds 

 British against 10 millions foreign. Variations in the import duty 

 have had much to do with these fluctuations. 



COFFER-DAM. A temporary enclosure around the position intended 

 to receive the foundations of a structure to be built in water, so con- 

 structed as to allow the water to be pumped out of the space enclosed, 

 and the building operations to be subsequently conducted " in the dry." 

 Coffer-dams are used when the depth of water at the place under 

 consideration is very great, and the importance of the structure or 

 the nature of the subsoil, are such as to render it inexpedient to 

 employ the diving-bell, or to resort to the use of caissons, or of concrete 

 foundations within close-piled enclosures. [BiuouE.] They may IK, 

 according to their depth, either simple banks of earth ; or timber-walls 

 backed with earth ; or double linings of timber filled in with imperme- 

 able clay ; or, finally, boxes or cases of wood, filled in as before with 

 clay. The complication of the framing, or of the cross strutting of a 

 coffer-dam, will, of course, depend on the effort to which it is to be 

 exposed ; and in deep tidal rivers these structures become very costly 

 and important preliminary works in the erection of bridges, docks, 

 wharves, &c. 



The thickness of a coffer-dam, of whatsoever material it may be 

 composed, is regulated by the consideration that it must be able not 

 only to resist the dead action, so to speak, of the water to be excluded, 

 but also its live action, or shock. It is customary, therefore, to mako 

 the thickness of simple earthen dams equal, on the average, to their 

 height ; and for this reason their use must be confined to such positions 

 only as would allow so much room to be devoted to the purpose, and 

 when the depth becomes at all considerable, the mixed systems of con- 

 struction must bo resorted to. In the case of a simple timber dam, 

 backed with earth, the timber acts partly to resist the statical action of 

 the water by means of its own transverse strength, and partly to 



