SCIENCE 
7 SINGLE COPIES, 15 cTs. 
Vou. VI. No. 132. FRIDAY, JULY 9, 189 (. ANNUAL SUBSCRIPTION, $5.00. 
Queen X=Ray Apparatus. 
° UNIVERSITY OF PENNSYLVANIA, 
Complete Outfits / . Department of Physics. 
Philadelphia, April 16, 1897. 
QUEEN & Co., INC. 
Gentlemen :—Your new auto- 
matic X Ray Tube which I have 
been using for the last week or more 
has certainly proved itself most 
satisfactory. I have never had the 
least trouble with the automatic 
adjusting attachment, the vacuum 
remaining constant during an ex- 
posure of whatever degree desired. 
I regard the Queen self-regulating 
attachment as the greatest im- 
provement which has been made 
in X-Ray tubes since the introduc- 
tion of the *‘ Focus Tube.’’? Every- 
one who has done radiographic 
work knows that the hip joint is 
perhaps the most difficult part of 
tbe human anatomy to produce a 
good picture of. Until the last 
week I never have gotten a really 
good hip with a less exposure than 
ten or fifteen minutes. The last 
trials were made with therew tube, 
oue with an ex posure of three min- 
utes, and the other with an expos- 
ure of one minute. The latter is 
excellent and the former is the best 
I bave yetseen. Ishalltake pleas- 
ure in sending you a copy of one of 
EneRe: Cone at ane youron the 
results of your efforts at advance- 
SEND FOR DESCRIPTIVE ment, J am, very sincerely, 
CIRCULAR, No. 204. . ARTHUR W. GOODSPEED. 
Queen Self-Regulating X=Ray Tube 
HAS THESE ADVANTAGES OVER ALL OTHER FORMS: 
(1.) ADJUSTABLE VACUUM; (2.) AUTOMATIC REGULATION OF VACUUM; 
(3.) LARGE CURRENT CARRYING CAPACITY; (4.) LONG LIFE. 
.-for.. 
Battery 
-- Or.. 
of latest and most 
improved design. 
BASH 
Microscopes, Engineering Instruments, Physical and Chemical 
Apparatus, Electrical Test Instruments. 
Catalogues and Circulars 
on application to QUEEN & Co., INC., 
New York Office: 116 Fulton St. 1010 Chestnut St., Philadelphia. 
