Show I L I Silent Sound Waves Tell ell Secrets About Makeup of V Various Liquids BALTIMORE AP Sound waved which cant can't be heard projected through a liquid and reflected back again are being made to tell tel what the substance is what kinds kInd of chemicals and how much of each make malte it up whether it contains any impurity and the extent to which it itcan itcan can be compressed They have been harnessed to this task by Dr J. J C. C Hubbard Johns Hopkins physicist and are regarded as promising the development ot of a 3 anew new unshod ot of precise chemical analysis analysis an- an which will be of great value to science and industry His metHod Dr rd Hubbard believes on the strength or of experiments he has been able to com complete lete thus far apparently can be applied as accurately accurately ac- ac to the analysis of liquids as the spectroscope stud study of light I waves has proved in the of sugar metals and other solid ele- ele ments The sound waves naves he employs employs- are of the supersonic vibrations variety of such great rapidity that they cannot cannot can can- not be detected by the human ear They are sent through the liquid under examination and Its effects on their speed and amplitude measured measured mea mea- with an apparatus no lar larger r than a small fruit jar which was devised by Dr Hubbard and Alfred Allred Loomis New York banker and phy- phy leist in the latter's laboratory at Tuxedo Park N N. Y The speed with whIch which- a sound wave passes through a I liquid Dr Hubbard explains is always the same and Is characteristic of that liquid Passing through any other liquid It has a different speed characteristic char char- ot of that substance His His J experIments also indicate that each liquId absorbs or deadens sOUnd waves to a specific extent different from the absorbing power of at all other liquids Knowing the speed with which sound travels through a liquid h he says the extent to which It can be compressed another characteristic whIch distinguishes it from all other can liquids be calculated Th The absorption absorption ab- ab I sorption of sound in liquids he her has found depends not on their thickness thick ness or but on the ilia distribution of the Positive and n tive chunks of electricity that makes makes makes' up the different kinds or of molecules which form them Thus ho points out by measurIng measuring ing the absorption of f a sound wave in a liquid It t Is possible to find out the electrical nature of its mole mole- cules If as his experiments Indi- Indi sate ate no two liquids have the same deadening effect on sound such measurements will provide a complete complete com com- index to the molecules of all of these substances which will have havea a large field of usefulness in the in-the the rapidly expanding field of physical chemistry The apparatus Dr Hubbard Is using Is known asa as' as n. n sonic Interferometer meter and is 11 a refinement of developed during the war to make depth soundings and detect the presenCe ot of hidden submarInes by bythe the now familiar echo ho method To Tomake 0 make them effective the navy had to find out how fast sound waves travel in sea water an operation which occupied a cruiser and In- In the Use of depth bombs and various instruments The same facts can be obtained with in a few minutes minutes min min- utes now Dr says by putting putting put put- ting the water waler In the interferometer and measuring high frequency sound waves as through it Filled with pure distilled water In which the speed ot of sound waves has been worked out with extreme care the interferometer has been found he declares to provIde a t. t means of measuring radio waves 0 O times as accurate as as' as that of any ot of the much more expensive apparatus commonly sold Old for that purpose |