Proceedings oE the Polytechnic Association. 719 



tuted. The fluid was then diluted with water, and one-half of it 

 distilled; the distillate was found to consist chiefly of ether. The 

 residue, on further concentration, gave off nitric acid vapor, and, on 

 cooling, crystals of oxalic acid were separated. 



Impkovement in Distillation. 

 The troublesome "bumping" peculiar to certain liquids maybe 

 prevented by a device described by P. Pellogio. A glass tube as 

 laro-e as practicable is inserted in the tubulus, reaching nearly to the 

 bottom of the retort. The upper end of the tube is bent at nglit 

 anc^les, and drawn out to nearly capillary size, through which com- 

 munication is established between the outer air and the interior ot the 

 retort. By this means methylic alcohol, sulphuric acid, petroleum 

 residues, and other liquids may be distilled as regularly as water. 



Ventilation of Stock Sheds. 

 Mr. Mechi, the well-known English agriculturist, says on this sub- 

 ject • "When farmers see my twenty bullocks in one covered and 

 inclosed shed, thev frequently exclaim, ' Can they be healthy here V 

 That is a very proper remark, for unless the ventilation were perfect, 

 they could not be healthy so closely packed in a limited space As 

 my system of ventilation appears to keep my animals (although closely 

 packed) in perfect health, I will describe it. A portion of the center 

 of the roof is raised abore the rest, with louver-boards on each side ; 

 but the wind is not allowed to blow through from one side to the 

 other, for a board, a yard or more in depth, is dependent from the 

 roof so that the current of air coming through the louver-boards is 

 deflected and passes downward, driving the foul air through the 

 opposite ade or louver-boards, or through the holes in the top of the 

 walls under the wall plate. The circulation, thus constant and periect, 

 was seen bv means of steam which otherwise could only have been 

 surmised. In sheds where two bullocks only occupied twelve by 

 eight feet, for twenty years there has not been the loss of an animal, 

 although many lots have been fattened there, some remaining from 

 calves until two years old." 



Stea^i Koad-Eollee. 

 The town council of Shefiield, England, has put in use a steam 

 roller for smoothing newly graded streets. It consists of four wheels 

 or rollers, each two feet wide. The two front wheels are placed three 



