563 



BLASTING BLEACHING. 



states, the offence of blasphemy, not being a subject 

 of special statutory provision, is only punishable 

 either as an offence at cmiiinmi law, or a violation of 

 tin statute laws against profane swearing. The of- 

 fence, considered only as a violation of positive sta- 

 tutes, would he liable to a great diversity of puiiMi- 

 nient in the different states, from a fine of two shillings 

 iiinl six-pence, in some, to an imprisonment not 

 exceeding a period of five years in others. Viewing 

 this subject in a philosophical, religious, or political 

 view, it would be difficult to lay down any general 

 principles applicable to different states of society; 

 bat the prevailing principle on tliis subject in the 

 I nited Slates, and that to which the laws and opin- 

 ions of other countries are strongly tending, is, that 

 any one may profess or oppose any doctrine, provided 

 he inculcates his principles, whether orally or in 

 writing, in suclt manner as not to commit a flagrant 

 violation of decorum: what acts or words will con- 

 stituie such an outrage must evidently depend upon 

 the state, of the society. 



BLASTING ; the technical term for splitting any 

 object by means of gunpowder. Many accidents 

 have occurred in blasting, in consequence of the 

 erroneous notion, that the more firmly the shot is 

 rammed home with the wadding, tile more effective 

 will be the explosion. The operations of this nature, 

 lately carried on at Gallon hill, in the formation of 

 the new approach to the city of Edinburgh, have 

 proved beyond a shadow of doubt, that dry sand may 

 be placed loosely over the powder, and the explosion 

 be as effective as if the firmest rammed wadding had 

 been employed. The train is led to the shot by 

 means of a straw filled with powder, and the whole 

 operation may be conducted with the most perfect 

 safety. 



BLAZONING, or BLAZONRY, in heraldry; the deci- 



Ehering of coats of arms, from the German blasen, to 

 low, because the herald blew a trumpet, and called 

 out the arms of a knight, when he entered the lists at 

 a tournament. See Heraldry. 



BLEACHING is the art of whitening linen, wool, cot- 

 ton, silk, wax, also the materials of which paper is 

 made, and other things. It is shown, by experience, 

 that organic bodies, after being deprived of life, and 

 becoming solid and dry, lose their colour, and become 

 white by the influence of the air and the sun-beams. 

 Upon this fact, the manner of bleaching, which was 

 formerly in use, is grounded: since, however, the 

 bleaching in the sun commonly requires a whole sum- 

 mer, Berthollet, in the year 1786, first proposed the 

 use of chlorine. This, it is known, has so little 

 corrosive power, that, if diluted, it may be taken 

 inwardly in a considerable quantity. 



The method proposed by Berthollet received seve- 

 ral improvements from Watt, and especially from Mr 

 Tennent of Glasgow, who, in 1798, took out a patent 

 for bleaching powder, commonly called the chloride 

 of lime. The patentee, who still continues to be the 

 most extensive manufacturer of this article in Great 

 Britain, made some improvements on the original 

 process, by which he was enabled to double the pro- 

 portion of chlorine, the only bleaching principle which 

 the powder contains, and the composition, as at pre- 

 sent manufactured, is as follows : 



3 atoms of chloride of calcium = 21 

 1 atom of chloride of lime =11 



32 



In the bleaching of cotton cloth, the pieces, after 

 being singed (See Singeing), and steeped in cold wa- 

 ter until they are completely soaked, are subjected to 

 the action of the wash or dash wheel (See Calico print- 

 ing). They are next put into an iron boiler in layers, 

 sach layer being covered with a solution of lime and 



water of the consistence of cream, the quantity of 

 lime being one thirty-fifth of the weight of the cloth. 

 The cut below will illustrate the form of the boiler. 

 The fire acts upon the malleable iron pan A A, se- 

 parated by a false bottom C C from the upper part 

 B B of cast iron, in which goods are contained. 

 There being considerable pressure upon the liquid in 

 the pan A A, it does not boil until its temperature is 

 raised considerably above 212; but in that part where. 

 the tube 1) opens into the pan the pressure is less, so 

 that the boiling commences in the tube. A mixture 

 of steam and water is sent up the tube, but is thrown 

 back into the boiler by the cap E, making room for 

 another supply. The liquor gradually fillers through 

 the goods, and falling through the false bottom 

 pierced with holes, the pan is supplied, and thus the 

 process continues. 



B 



The requisite quantity of water is then poured in, and 

 the process of boiling continued for about eight hours, 

 when the cloth is again subjected to the action of the 

 wash wheel, so that the lime shall bo entirely re- 

 moved ; for if any .of the lime were allowed to remain, 

 the fibre of the cloth would suffer injury. The next 

 part of the process is the application of the bleaching 

 powder, which is dissolved in cold water in the pro- 

 portion of 388 pounds of chloride of lime to 971 

 gallons of water, this quantity being sufficient for the 

 bleaching of 700 pieces. The specific gravity of the 

 liquor ought to be 1-02, but the strength of the 

 chlorine, which does not influence the specific gravity, 

 ought also to be considered; the method of ascertain- 

 ing which, will be described under the article Chlorine. 

 In this cold solution of bleaching powder, the cloth is 

 allowed to steep for six hours. It is then withdrawn 

 and thoroughly washed, and, possessing much more 

 whiteness than before, it is prepared for the souring 

 process, by which the colouring matter is yet more 

 discharged. A liquor is formed of dilute sulphuric 

 acid, i. e. oil of vitriol and water, in the proportion of 

 four parts of the acid for every hundred of the water ; 

 were the solution weaker than this, it would be in- 

 effective, and if stronger, it would be injurious by 

 corrosion. The cloth is allowed to remain in this 

 cold sour for about four hours, during which time 

 the sulphuric acid combines with ana extracts the. 

 oxide of iron which the cloth contains, and also 

 the lime which it had imbibed during the former 

 processes. 



The cloth being now carefully washed, is boiled 

 for eight hours in a lye, composed of carbonate of 

 soda, made caustic by quicklime, 48 pounds of the 

 soda being used for every 2100 pounds of the un- 

 bleached cloth. The cloth is then washed, and thus 

 prepared to undergo, for a second time, the action of 

 the chloride of lime this solution being of less 

 strength by a third than that formerly employed. 

 After the cloth has lain in this solution for five hours, 

 it is taken out, washed, and put into a sjur similar 

 to that formerly used, where it is allowed to remain 





