208 Proceedhi(]s of tite lioiial JSocieti/ of Victoria. 



The results at whicli he arrived are given ivithout any 

 investigations on page .'J 12 of Williamson's "Integral 

 Calculus." From question 19, as there enunciated, it would 

 appear that Townsend did not perceive that the envelope of 

 the plane is an ellipsoid ouly when the prescribed moment 

 of inertia is not less than a certain determinable magnitude ; 

 or that it is a Hyperboloid of One Sheet for all values less 

 than such limiting value. Nor does it a])pear tliat he 

 considered the case in which the envelope of the plane is 

 a Hyperboloid of Two Sheets, or any limiting values of the 

 moment of inertia. 



