STAINED GLASS 879 



thoroughly bleached, and a fourth method was tried. The sponges -were well washed 

 in hot diluted soda-lye, then placed in a bath of weak hydrochloric acid and hypo- 

 sulphite of soda, using only half the quantity of hyposulphite that was used in tho 

 first experiment, and a very satisfactory result was thus obtained. 



SPONTANEOUS COMBUSTION. Major Majendie has recently (1674) com- 

 municated to the Eoyal Artillery Institute some interesting experiments made by Mr. 

 Galletly on this subject. It was found that cotton-waste, soaked in boiled linseed oil 

 nnd wrung out, if exposed to a temperature of 170 Fahr., oxidised in 105 minutes. 

 Raw linseed oil required from four to five hours before igniting ; rape and olive oils 

 five to six hours ; lard oil four hours ; castor oil one day ; and, in one trial, olive oil 

 ignited in 100 minutes. Sperm oil did not char the waste. His theory is, that the 

 oil by being spread and finely divided among the fibres of the waste, has its absorbent 

 power towards oxygen greatly increased, much as a bloom of iron will oxidise rapidly 

 in process of manufacture if exposed to the air. It was also found that ignition took 

 place more quickly with silk waste than with cotton. A scientific journal, commenting 

 on this report, declares that the sperm oil of the experiment must have been adulterated 

 with petroleum, which has a tendency to repress such oxidation, as it has been proved 

 by other trials that sperm oil will rapidly absorb oxygen as certainly as other oils ; 

 but no case of spontaneous combustion has yet been reported from coal oils. 



Many fires have occurred in woollen and cotton mills from the careless leaving of oily 

 waste in warm places, especially during tho summer months, and for safety it is 

 necessary that such waste be removed daily. Shoddy mills, where the rags after 

 being oiled are torn into fibre, are especially dangerous, as either from inferior oil 

 used, or the adulteration of No. 1 lard oil with the dangerous cotton-seed oil, the 

 shoddy often takes fire in the bags before leaving the works, or soon after reaching 

 the mill where it is to be manufactured. Two other causes may aid in causing such 

 fires : packing the material too soon and too tight, and putting on too much oil. The 

 latter is a profitable arrangement, and too much practised. The only safety for those 

 buying is to examine the heat of each lot as received, and, if possible, open out into 

 a pile ; or, if not, let each bag be slit open and exposed to the air. The Editor of 

 this Dictionary was called upon to investigate tho causes which led to the destruction 

 by fire of H.M. ships the ' Imogene ' and the ' Talavera ' in Devonport dockyard. He 

 traced it, beyond all question, to a large bin, in which, with great carelessness, oil, 

 anti-attrition, oakum, and tow, which had been used by the shipwrights and others in 

 wiping the oil from their tools after sharpening them, had been allowed to accumulate ; 

 and reported to this effect to the Admiralty. 



Spontaneous combustion, arising from the rapid absorption of oxygen by the fixed 

 oils, except petroleum, is now attracting much attention, and cannot be too much im- 

 pressed on the public mind. The recent fire at Portland, Maine, is declared to have 

 arisen from the leakage of linseed oil, stored alongside of rags. In May last two 

 fires, discovered first in the stable, and afterwards in the dwelling of a gentleman at 

 Bedford, Pa., were traced directly to rags saturated with linseed oil, which painters 

 who had been graining shutters had thrown into corners. At Jamestown, New York, 

 a workman, who had been cleaning furniture with linseed oil, threw aside his oily 

 apron crumpled together, and in a short time it was found in a state of ignition. 

 SPOON MANUFACTURE. See STAMPING OF METALS. 



SPRUCE BEER is prepared as follows : Essence of spruce, half a pint ; pimento 

 and ginger bruised, of each 4 ounces ; hops, from 4 to 3 ounces ; water, 3 gallons. 

 Boil for ten minutes, then strain and add 11 gallons of warm water, a pint of yeast, 

 and 6 pints of molasses. Mix and allow the mixture to ferment for twenty hours. 



SPRUCE, ESSENCE OP, is prepared by boiling the young tops of the Abies 

 nigra, or black spruce, in water, and concentrating the decoction by evaporation. 



STAINED GLASS. Under GLASS, a general account of the processes for 

 colouring glass has been given ; for the manufacture, however, of stained glass for 

 windows some special details have been reserved for this place. When certain 

 metallic oxides or chlorides, ground up with proper fluxes, are painted upon glass, 

 their colours fuse into its surface at a moderate heat and make durable pictures, which 

 are frequently employed in ornamenting the windows of churches, as well as of other 

 public and private buildings. The colours of stained glass are all transparent, and 

 are therefore to be viewed only by transmitted light. Many metallic pigments, which 

 afford a fine effect when applied cold on canvas or paper, are so changed by vitreous 

 fusion as to be quite inapplicable to painting in stained glass. 



The glass proper for receiving these vitrifying pigments should be colourless, uni- 

 form, and difficult of fusion ; for which reason crown glass, made with little alkali, 

 or with kelp, is preferred. When tho design is too large to be contained on a single 

 pane, several are fitted together and fixed in a bed of soft cement while painting, and 

 then taken asunder to be separately subjected to tho fire. In arranging the glass 



