1896 THE MICROSCOPE. 191 



of the northern border of Illinois and about seventy-five 

 miles northwest of Chicag-o. The air there is free from 

 Chicago's smoke. 



The object-glass is within a fraction of 42 inches in di- 

 ameter — being- exactly 41^8 inches. The great objective 

 of the Lick observatory — the next larg-est one — was made 

 by Alvan Clark, the father of the present telescope-maker, 

 and is 36 inches in diameter. The tube, or focal distance, 

 in the Lick telescope is 57 feet. This new and still bigger 

 glass is to have a tube 61 feet long. It is now being fin- 

 ished by Warner & Swasey, at Cleveland, Ohio, who will 

 mount the instrument equatorially, and who have already 

 made the ring for the objective. In this great refracting 

 g-lass the sheet of crown glass is 3 inches thick at the mid- 

 dle, 1}( inches thick at, edg-es, and weighs 205 pounds ; 

 while the flint glass weighs 301 pounds making 506 pounds 

 for the objective irrespective of the ring. The whole will 

 weigh about 1,000 pounds, and it may be a problem to keep 

 the big glass from bending, after all. 



The cost of this giant lens is over $100,000. Its raw ma- 

 terial (which cost $40,000 in Paris) was repeatedly melted 

 by Mr. Clark, for the sake of purity and perfection. It 

 has taken two and a half years to make this big object- 

 glass. 



The elaborate work of packing this precious product, 

 for transportation to Lake Geneva, Wis., will be" careful 

 and costly. First it will be tightly wrapped and sewed up 

 in flannel; then thickly covered with layers of soft paper ; 

 then wrapped in hard paper, and the whole encased in a 

 bed of curled hair in a strong box. This, placed within a 

 larger box and mounted upon springs, on all sides of the 

 inner box, and packed in excelsior, will rest in the middle 

 of an easy going parlor car, and four men will go with the 

 precious freight, which may be destined to reveal interest- 

 ing things concerning "other worlds than ours." 



Prof. Koch has been sent to South Africa by the Ger- 

 man government to investigate the causes of the Kinder-, 

 pest. 



