PROCEEDINGS. 
395 
pound of coal. The present consumption is about 50 gallons per 
week. The speaker finds this an ideal source of power for auto¬ 
mobiles, and for submarine and aerial navigation, except for its 
cost; 17 gallons drive his vehicle 50 to GO miles. It is useful in 
manufacturing food extracts and chemicals and has important 
medical uses. 
552d Meeting. April 26, 1902. 
Vice-President Marvin in the chair. 
Twenty-one persons present. 
Mr. W. J. Spillman described Mechanism for computing 
normal equations from observational equations. This has as 
many centrally pivoted levers as there are equations to be com¬ 
bined; each lever is graduated both ways from the center and 
carries as many slides as there are terms in each equation; these 
slides are set each on the graduation corresponding to the co¬ 
efficient of the proper terms, and cords run from homologous 
slides over pulleys to pointers each moving over a scale. Multi¬ 
plication is performed by moving the end of any lever over a 
graduated arc a distance corresponding to the multiplier. When 
all the multiplications have been performed the sum of the pro¬ 
ducts of the homologous terms are read from the pointers. [Not 
published.] 
Mr. Gilbert spoke briefly of a somewhat similar machine he 
had devised several years ago. 
Mr. L. J. Briggs then spoke on The adsorption of gases and 
dissolved salts by quartz and glass. The weights of vapor of 
water and of carbon dioxide adsorbed by finely powdered quartz 
were found closely proportional to the pressure of the vapor or 
gas. With very dilute solutions of chlorides, carbonates, or 
hydroxides. of sodium, potassium, and ammonium the amount 
adsorbed increases much less rapidly than the concentration, and 
appears with these salts to be dependent on the acid radical rather 
than upon the basic element. Attention was called to the im¬ 
portance of such investigations in their bearings on problems 
