1870. J On Practical Scientific Instruction. 219 



occur in this substance. Faraday said of physical and chemical 

 phenomena, " the little that is known is a great and wonderful 

 indication of that which is to be known." 



The hidden difficulties which beset a manufacturer are not un- 

 frequently so inscrutable that the present state of knowledge hi 

 science fails to explain them. Who can tell why it is that wire- 

 work of brass or german-silver becomes gradually brittle by lapse 

 of time ? or why varnish made in the open country has different 

 properties from that made in a town ? or why silk dyed in Lyons 

 should possess a finer colour than the same silk dyed by the same 

 process in Coventry ? With our present extremely imperfect know- 

 ledge of Physical and Chemical science, we can perhaps hardly form 

 an idea of the infinitely complex nature of the phenomena which 

 it presents. 



One of the inevitable results of all these difficulties in manufac- 

 turing processes and of unscientific management, is the production 

 of a large amount of goods of an inferior quality ; and useless goods, 

 technically called " wasters," the cost of which has to be laid upon 

 the saleable ones, and thus the price of the latter is enhanced to the 

 consumer. For instance, flint glass discoloured by iron has some- 

 times to be sold at a loss for making common enamel ; waste win- 

 dow-glass has to be sold as " rockery " for ornamenting gardens, 

 and defective articles of glass or metal have to be re-melted. 



Many of these difficulties arise from the inaccuracy and care- 

 lessness of the workmeD, and would be lessened by the more general 

 diffusion of scientific knowledge. If workmen and managers had 

 more preparatory scientific training, and all apprentices were suit- 

 ably educated in science, not only would the foregoing sources of 

 loss and expense be lessened, but workmen would acquire greater 

 habits of caution, and such accidents as arise from the want of these 

 in the management of steam-boilers, explosive substances, and mines, 

 would occur less frequently. A miner never having seen an explo- 

 sion of coal-gas and air in a scientific lecture, does not adequately 

 believe or realize the dangerous nature of the mixture ; and work- 

 men in general in this country do not sufficiently believe in the 

 fearful properties stored up in substances, and in the forces of na- 

 ture, because they have not seen them demonstrated by experiments. 

 It is a curse of the ignorant to be incautious in actual danger, and 

 to suffer terror where no real harm can occur. 



Many of our working-men are fearfully reckless in circum- 

 stances where a small amount of scientific knowledge obtainable by 

 witnessing a few experiments would show them the existence of 

 extreme danger. We read accounts of barrels of gunpowder being 

 kept in blacksmiths' shops ; of cans of damp gunpowder being set 

 on a hob to dry; of nitro-glycerine being conveyed in a jolting cart, 

 and of its being used to grease the axles of wheels ; of a lighted 



