The boy's playbook of science : including the various manipulations and arrangements of chemical and philosophical apparatus required for the successful performance of scientific experiments / by John Henry Pepper ; illustrated ... by H.G. Hine.

  • John Henry Pepper
Date:
1860
Catalogue details

Licence: Public Domain Mark

Credit: The boy's playbook of science : including the various manipulations and arrangements of chemical and philosophical apparatus required for the successful performance of scientific experiments / by John Henry Pepper ; illustrated ... by H.G. Hine. Source: Wellcome Collection.

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    vme, and tlie end of the glass tube placed m a tumbler containing a smaU quantity of water coloured blue with sulphate of mdigo. it a tolerably large jar containing hydi-ogen is now placed oyer the porous cell bubbles of gas make theii- escape at the end of the tube, because the hydron-en diffuses itself more rapidly into the porous cell than the air which it akeady contains passes out. When the ]ar is removed the reverse occm-s, hydrogen diffuses out of the porous ceU, and the blue liquid rises in the tube. This diffusive force prevents the accumulation of the various noxious gases on the eartli, and spreads them rapidly through the great bulk ot the atmosphere sui-roundiug the globe. ,1, i Althouc^h air and other gases are invisible, they possess the property of impenetrability, as may be easily proved by various experiments. Havin'^ opened a pair of common beUows, stop up the nozzle securely, and it!s then impossible to shut them; or, fiU a bladder with air by blowino- into it, and tie a string fast round the neck; you then tndthat you cannot, without breaking the bladder, press the sides together It is customary to say that a vessel is empty when we have poured out the water which it contained. Having provided two glass_ vessels lull of water, place each of them in an empty white pan, to receive the over- Fig. 6 represents the water overflow- ing, as the glass, with the orifice closed, is pressed down, proving the impene- trability of air. Pig. 7. The orange has entered the glass vessel, and ^the air having passed from the orifice, no water overflows. flow, then lay an orange upon the surface of the water of one of them, and being provided with a cylindrical glass, open at one end, with a hole in the centre of the closed end, place your finger firmly over the orifice, and endeavour, by inverting the glass over the orange, and pressing upon the surface of the water, to make it enter the interior of the glass cylinder ; the resistance of the air will now cause the water to overflow into the white pan, whilst the orange wiU not enter. The
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