ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 817 



3. To these may be added the secondary marking on diatoms, e. g. 

 Coscinodiscus asterompJialus, &c. 



4. The fracture passing through the secondary markings, such as 

 (a) Triceratium, (b) Isthmia nervosa. 



5. The secondary markings in the areolations on the hoop of Isthmia 

 nervosa in balsam. 



All these tests are intended for solid cones of direct light of various 

 apertures. Two classes of tests are comprised in this list. The first, 

 and perhaps the best, is the way a fairly large test is presented. 1, 2, 

 4 (a), and some of 3 are in this class. 



The other class consists in the possibility of making out the test at 

 all. 4 (&), 5, and some of 3 are in this class. 



Fasoldt's Test-plates.*— Mr. C. Fasoldt replies to Dr. E. H. Ward's 

 report on the examination of one of his test-plates. He claims that Dr. 

 T. F. C. Van Allen " resolved every band up to and including the 

 200,000 lines per inch in the presence of Dr. Ward." Also that " a 

 number of gentlemen " have resolved all bands up to and including the 

 200,000, " seeing plainly lines and spaces." 



" The successful resolution of the lines is not dependent on the mode 

 of ruling, but on the eyes. And, considering the admitted inability in 

 Dr. Ward's eyes, it would seem no more than an act of justice to all 

 concerned had the Doctor delegated his position on the committee to 

 some one whose eyes were more reliable, and who would have been 

 equally unprejudiced as himself in making the investigations. Good 

 eyesight is certainly an essential factor in such close tests as the 

 resolution of even 120,000 lines per inch, and there may perhaps be a 

 reasonable doubt whether the Doctor was able to resolve the 120,000 

 lines per inch, as he claimed he was able to do. His admissions are, 

 however, very candid, and his report can, therefore, have no value as to 

 the number or resolvability of the rulings under discussion." 



Microscopical Optics and the ftuekett Club Journal. — When an 

 esteemed friend goes astray it is often very perplexing to know what 

 course to take. Are we to leave him unadmonished out of fear of 

 impairing the ties of friendship, or are we to openly recognize the evil 

 of his ways and act accordingly ? The friend who has more especially 

 brought this dif&culty to mind at the present moment is the Quekett 

 Microscopical Club, for which we retain unimpaired all the regard of 

 early days, and the evil in this case relates to some papers printed in 

 its Journal. 



We recently had occasion to comment upon some comical blunders 

 occurring in a paper in which optical principles were turned upside 

 down in a very naive manner, but the last part of the Journal goes 

 beyond even tlaat extraordinary paper, and we find page after page 

 containing the most terrible nonsense that has ever been published 

 hitherto in a microscopical journal. The paper to which we more particu- 

 larly refer is one entitled " On True and False Images in Microscopy ,"| 

 the writer of which, as he shows in paragraph after paragraph, has 

 not taken the trouble to master even the rudiments of the subject about 

 which he writes, although he starts with the ludicrous statement that, " to 

 him the subject presents no difficulty whatever " ! One of the more strik- 



* The Microscope, viii. (1888) pp. 220-3. 



t Joarn. Quek. Micr. Club, iii. (1888) pp. 267-72. 



