Show Whistle Helps Measure Pressures in Engines How lIow to measure the volume of the compression space above the pistons pistons pis pis- pis tons of at an Internal combustion engine engine en en- gine without removing the cylinder der head has hu been solved b by the invention invention in in- of at a whistling gauge The rate of vibration of ot the air in the cylinder head is compared with that of air In an adjustable adjustable ad ad- and calibrated chamber of 0 known volume b by employing two identical whistles one a attached to toone toone toone one sparkplug port of the engine and the other to the adjustable cham ber The whistle whistles are blown blo by au air having a common supply and contant con con- slant tant pressure says laYs Popular Me Me- The pitch of at the notes of the whistles on 0 the two chambers depends upon the volume of ot air contained con lathed in them Thus when notes noles of the same me pitch are produced the volumes of the two chambers are equal |