69 



STAR-FOET. 



STARCH. 



770 



lately dissolved, taken away, and determined, and that all statutes 

 giving such jurisdiction should be repealed." 



STAR-FORT, a kind of redout inclosing an area, and having its 

 lines of rampart or parapet disposed, on the plan, in directions making 

 with each other angles which are alternately salient and re-entering, as 

 a star is usually represented. This construction is adopted when the 

 work is intended to contain, for some time, the stores of an army, or 

 to secure some important part of the position which the army occupies. 

 The magistral line of the work may be traced by first laying down a 

 polygonal figure, regular or irregular, as the ground may permit, and 

 then upon each of its sides forming an equilateral triangle : the interior 

 capacity and the quantity of fire will evidently be increased as the 

 polygon has a greater number of sides ; but the importance of the work 

 in seldom so great as to render it necessary to form it on a polygon 

 superior to a hexagon or an octagon ; and the latter polygon, while it 

 admits of being easily traced, allows the re-entering angles between the 

 aides of the triangles to have a degree of obtuseness sufficient to avoid 

 the risk that the defenders of the faces on each side of such an angle 

 might fire upon one another. As it is found that soldiers fire nearly 

 perpendicularly to the face of the parapet behind which they stand, a 

 greater obtuseness would cause the lines of fire to diverge so far from 

 the direction of the adjacent face as to prevent the ditch of the latter 

 from being effectually flanked. 



A star-fort on an octagon may, if the ground is level, be traced by 

 laying down a square, and, upon the middle of each of its sides, an 

 equilateral triangle, whose base is one-third of the length of such side ; 

 or, more regularly, by transferring half the diagonal of the square to 

 each side, from the four angles ; the distances between the extremities 

 of these half diagonals are the sides of an equilateral octagon, and upon 

 these sides equilateral triangles may be formed. The subjoined cut 

 represents the magistral line of half a star-fort with eight points, con- 

 structed in this last manner. If the polygon had more than twelve 

 sides, the re-entering angles would be acute ; and, agreeably to the 

 above supposition concerning the direction in which soldiers fire, the 

 defenders on the adjacent faces might annoy one another. 



That the fire of musketry may be sufficiently effective, it is con- 

 sidered proper that the lengths of the several faces should not be less 

 than thirty yards ; and a star-fort whose faces are of much greater 



length w capable of containing a garrison more numerous than that 

 which would be required for the end proposed by such a work. A 

 star-fort with six or eight points has a great advantage over a simple 

 redout, though ita construction is less simple : the crossing fires from 

 the faces seriously impede the advance of the enemy towards the salient 

 points ; and the assailants, in passing the ditch, are completely exposed 

 to the view of the defenders. 



During the Seven Years' War, the king of Prussia's intrenched camp 

 at Jauernick contained a star-fort on a rising ground in its centre, from 

 whence the movements of the Austrians could be observed ; and in this 

 work the king's tent was pitched. The position taken up on the Nivelle 

 by Marshal Soult, while the British army was acting in the south of 

 France (1813), was protected by a strong star-fort. The work was 

 constructed on a terrace below the summit of a mountain called the 

 Smaller Khune, and was intended to defend the entrance of a ravine. 

 A platform below the summit of a ridge of high ground near the 

 Bidaxsoa was, in like manner, fortified by a star-fort. 



STARCH (C,,H 10 O 10 ). Fecula; Amidm ; Amylaceous matter. The 

 substance known in commerce and in domestic life as starch, is usually 

 prepared from wheaten flour. Starch, however, exists in abundance in 

 very many other vegetables, so that, strictly speaking, the term is a 

 generic one. The flour of barley, oats, rye, arrow-root, sago, tapioca, 

 rice ; the greater part of the common potato, harico bean, lentil, 

 maize, millet, Ac., is starch. The starch from these various sources is 

 identical so far as composition is concerned ; the elements carbon, 

 hydrogen, and oxygen exist in exactly similar proportions in all. As 

 usually met with, the several varieties differ somewhat in taste, but 

 probably owing to admixture of traces of volatile oil. [ESSENTIAL 

 OILS, of Starch.] They appear also to slightly differ from each other 

 in capability of assimilation when taken as food ; a fact not yet satis- 

 factorily accounted for. 



To the naked eye starch presents a white glistening appearance, and 

 seems to be an aggregation of small shapeless particles. By the aid of 

 the microscope, however, it is seen to consist of beautiful regular ovoid 

 granules ; and under a magnifying power of from two to five hundred 

 diameters, each granule is found to be marked by a series of circles 

 converging from the circumference to a point termed the hiluin. The 

 size of the granule, the distinctness of the concentric lines, and the 



ABTS ASD SCI. DIV. VOL. VII. 



position of the hilum, are always the same in any one kind of starch, 

 but vary considerably in starch from various sources ; the microscope 

 is therefore of considerable aid in detecting the admixture of au inferior 

 with a superior variety, aud in determining the origin of a starch. 



Starch is insoluble in, and but very slightly acted upon by, cold 

 water ; nor is it really soluble in hot water. When, however, it is 

 heated with twenty or thirty times its weight of water its granules 

 swell and finally burst; if the whole be diluted and set aside, the rent 

 walls of the granules subside to the bottom of the containing vessel, 

 while their contents are so thoroughly mixed with the water that the 

 two can only be separated by very tedious processes. Starch is also 

 insoluble in alcohol or ether. Acids and alkalies, even when cold and 

 highly diluted, cause it to swell and form a paste aud finally convert 

 it into dextrin. Air-dried starch usually contains about eighteen per 

 cent, of water ; if more than this is present the starch has a tendency 

 to agglutinate when pressed between the finger and thumb ; moreover, 

 when projected on to a metal plate heated to 212 Fahr., it agglo- 

 merates into hard lumps forming a sort of artificial tapioca, no such 

 effect being produced if it has been properly air-dried. Exposed in 

 vacuo at a temperature of 60 Fahr., the amount of water is reduced to 

 fifteen per cent. (C^H^O,,,, 2Aq. ) and at 260 Fahr. to the minimum of 

 eight and a half per cent. (C^H^O^). At a higher heat than this, 

 starch is converted into dextrin. 



Starch combines with certain bases, the compounds have been 

 termed amylates ; that of lead contains (C la H 9 9 f 2PbO). 



Teat for Starch. Free iodine communicates a deep blue colour to 

 starch. The resulting body is called iodide of starch, but its con- 

 stitution has not yet been satisfactorily ascertained. The colour 

 disappears if the iodine be in excess, if the mixture be boiled, or if any 

 unstable organic matter, such as urine, be added to it. By bringing 

 iodide of starch into contact with yeast, M. Duroy has lately obtained 

 what he calls colourless iodide of starch, a sweet, gummy, uucrystal- 

 lisable neutral substance, very soluble in water, but insoluble in 

 alcohol. 



The amount of starch in various vegetables varies as they progress 

 towards maturity, and is much influenced by soil and climate. 



Wheat 

 Potatoes 

 Rice 

 Kye . 

 Oats 

 Barley . 



Wheat Slarch. Wheaten flour is mixed with water and exposed 

 to the air, with occasional stirring, for several weeks. During this 

 tune a portion of the gluten of the flour undergoes putrefaction : 

 fermentation is set up, and some of the starch is converted into 

 carbonic acid and alcohol, acetic and lactic acids are also formed. 

 During this change an exceedingly unpleasant prutrescent odour is 

 given off from the mass ; the starch, however, ultimately subsides in 

 the pure state, and colourless, the other matters with which it was 

 mixed in the flour, as well as some products of decomposition, remain- 

 ing in solution or floating on the surface as a scum, called slimes or 

 flummery. The latter was formerly given to pigs for food, but is now 

 used by the calico-printer as a resist paste. The peculiar, but well- 

 known columnar appearance of wheat starch, as met with in commerce, 

 is acquired during the drying opertion. The moist starch is cut up 

 into blocks about six inches square, and placed in carefully heated 

 stoves ; as the water evaporates the masses shrink and split up into 

 the characteristic irregular fragments. 



A preferable method of extracting starch from wheat-flour has lately 

 been introduced by Mr. Martin. It consists in kneading the flour into 

 dough with water, aud then washing on a sieve in a stream of water. 

 The starch is thus washed out, and nearly all the gluten remains 

 behind as a sticky mass. Slight fermentation is induced in the wash- 

 ings, whereby the remaining portions of gluten are destroyed, and the 

 starch is then dried. The gum-like gluten educed in this process is 

 dried, ground, and sold as semolina, or is mixed with flour and made 

 into maccaroni and similar pastes. 



Potato Starch, now largely manufactured on the Continent, is readily 

 obtained from the washed and rasped or grated potatoes by simple 

 kneading of the pulp in a stream of water on an inclined plate or fiuo 

 sieve ; the starch is carried off by the water, is allowed to subside, and 

 after one or two washings by decantation, is drained in boxes lined 

 with felt, and dried on floors of plaster of Paris. Potato starch does 

 not, in drying, assume the columnar form characteristic of wheat 

 starch. 



Rice Starch. For the preparation of this variety the rice is macerated 

 for twenty-four hours in a very weak alkaline solution, composed of 

 nearly half an ounce of caustic soda to a gallon of water ; it is then 

 washed, drained, reduced to a pulp, and again macerated in a fresh 

 quantity of soda-ley ; after brisk agitation and a short repose the 

 liquor, still containing the starch in buspcnsion, is poured off from the 

 vegetable fibre, which first deposits, and the starch, accumulated by 

 subsidence, is finally dried in the usual manner. The object of this 

 process is the solution of the gluten in the weak alkali. If the latter 

 be carefully neutralised by sulphuric acid the gluten is deposited in 



3 D 



