672 Transactions of the American Institute. 



the human voice. 

 Boucicault, the dramatist and actor, commenting on the Albert 

 Hall of Science and Art, London, in The Pall Mall Gazette, says 

 the human voice, when speaking with clear articulation, and sup- 

 plied from good lungs, will fill four hundred thousand cubic feet 

 of air (that is, set the whole in complete vibration), provided it 

 be inclosed in a proper manner, and the voice placed and directed 

 advantageously. The same voice, singings can fill, with equal 

 facility, six hundred thousand cubic feet. When singing, the vowels 

 are principally used, because it is necessary to dwell upon a note, 

 and we cannot prolong a consonant. In speaking, on the contrary, 

 we depend for articulation on the consonants; but their short per 

 cussive sound does not travel. Mr. Boucicault's last statement 

 seems erroneous; the sound of a consonant, or the timbre of a 

 musical instrument, is borne on the air- waves at a uniform velocity, 

 but these waves are constantly diminishing in density, and those 

 disturbances of the uniformity and smoothness, so to speak, of these 

 waves, which are made when a consonant is pronounced, would 

 become imperceptible more rapidly than the regular vibratory 

 action which gives us a perception of sound. In one sense, it may 

 be said that if a sound ceiises to be heard it does not travel, yet the 

 air-waves causing it continue to move, after the sound is no longer 

 perceived by the human ear; and each disturbance in the regu- 

 larity of this vibratory force is carried on with the same velocity. 

 Consonants are not heard so far as vowels, because in pronouncing 

 a consonant we cannot increase the density of air-waves as we can 

 when sounding a vowel. 



THE PRESSURE PROCESS OF BLEACHING. 



By the old process, the straw used as paper stock was submit- 

 ted to the action of chloride of lime in the beating or pulping 

 engine. Of course, only a small portion of the chloride was used 

 at one time, and the quantities of pulp bleached by it were small. 

 Last year it was accidently discovered at Rochester, N. Y,, that by 

 exposing the fibrous material to be bleached to a weak solution of 

 chloride of lime, or bleaching powder in a close vessel, under a 

 pressure of from one hundred and ten to one hundred and twenty 

 pounds per square inch, the vessel being slowly rotated on a hori- 

 zontal axis, perfectly bleached to a snow-white, one ton or more of 

 the material; and what is strange to relate, the larger the quan- 

 tity the more perfect the decoloration. When straw is to bo 



