348 THE AMERICAN MONTHLY ['Sov 



a microsco[te objective of uu iiicli ami a half focus to form 

 a second image, two iiu^lies and three-eighths in diam- 

 eter, on the ground-glass of the camera. The clouds 

 made sharp focusing impossible. Only an imperfect 

 focus was obtained. The clock of the heliostat kept the 

 image steadily on the ground glass. 



During the eclipse sensitized plates were substituted 

 for the grcund-glass. Exposures were made when the 

 clouds were thin enough to permit. Thus six negatives 

 were secured. The first print shows the moon's black 

 disc, advancing apparently from the north-east across 

 the sun's disc, while the second shows the moon's disc, 

 passing off to the west. 



This is the first record of an attempt to use photomic- 

 rography asi-tronomically. All of the necessary appa- 

 ratus could be easily packed in a trunk. If an unaided 

 telescope objective were used to project an image of the 

 size obtained, a focus of twenty-one feet would be re- 

 quired; and the lens would have a diameter of about six- 

 teen inches. Such an objecti\ e properly mounted would 

 result in an instrument ueaily half as large as the great 

 Lick telescojie, with its photographic objective. By 

 using a portrait b-ns having a focus of fifteen or sixteen 

 inches, a size commonly used for "cabinets" in [)hotog- 

 raphers' studios, instead of the portrait lens, the api)a- 

 ratus will produce a nt^gative image ecjiial in size to that 

 prodiKjed by thi; unaided Lick lens; or, li'a\ing the por- 

 trait lens in place, the same result could be obtained by 

 substituting for the microscope objective of one inch and 

 ah ilf focus, another of about double the power, — one of 

 lliree-(|uarters of an inch focus. Tlie Lick instrnnient 

 has a tube about fifty fi'i't loniiand foi'ty-two inches iu 

 iliameter. while this apiaratus has two tubes less than 

 one foot lonj^ and about one inch and six inches in 

 diameter respect ivejy. T" the smaller tube is attached 

 a camera with a bellows extciiiJinL: from one to six 



