October 2, 1899.] 



KNOWLEDGE. 



239 



The usual processes that are adopted for the hardening of 

 brain and similarly soft tissues, frequently result in failure bj' 

 reason of the pressure of the tissues on the hard surface of the 

 containing vessel, and the consequent mis-shapeuing of the lobes 

 and convolutions, or the rupturing of the delicate superficial 

 membranes. To prevent this, Prof. W. C. Krauss, of Nebraska 

 University, has devised a hardening receptacle which obviates 

 most of the disadvantages of the old method besides being 

 exceedingly simple and inexpensive. An oval tin pail, of from 

 four to six quarts capacity, with an ordinary handle and a tight 

 fitting cover, has a series of about ten hooks soldered on the 

 inside about one inch from the top of the rim. The convex 

 surface of the fresh biain is covered with a sheet of cotton, and 

 over this is placed a piece of netting. The whole is then lowered 

 gently into the ])ail containing the hardening fluid, and 

 suspended in it by means of the hooks. The brain thus under- 

 goes hardening in all directions at once, and does not lose its 

 normal symmetry. The cotton protects the convolutions from 

 being ruptured. 



Many workers have in their battery of objectives samples of 

 both the achromatic and apochromatic types, having their 

 favourites of both series. But this has necessitated two 

 sets of ej-e-pieces, the Huyghenian for the former, and the 

 Compensating for the latter ; but this will no longer be 

 necessarj-. because in the " Holoscopic '' eye-piece of W. Watson 

 »& Sons we have an eye-piece which has been specially devised 

 for both purposes. It consists of two tubes, the outer one 

 carrying the field lens, and the inner, or 

 telescopic one, having fixed to it the eye lens 

 and diaphragm. Carefully selected appro- 

 priate glasses are used for the lenses, and 

 when the telescopic tube is pushed in as 

 far as it will go, the eye-piece is an under- 

 corrected one, suitable for work with 

 achromatic objectives. As the lube is 

 drawn out, the eye-piece becomes in- 

 creasingly a compensating one, possessing 

 the so-called over-correction associated 

 with the compensating eye-pieces which are 

 used with the apochromatic objectives. 

 This eye- piece yields really beau tiful images, 

 and not only does it obviate the necessity 

 for two sets of eye-pieces, but it gives to 

 the worker a power of adaptation which he has not hitherto 

 possessed. Yery few of the apochromatic objectives have the 

 same amount of under-correction, consequently with the fixed 

 eye-pieces the over-correction is frequently too great. With the 

 ■' Holoscopic '■ eye-piece, the over-correction can be exactly 

 adjusted to the objective, and a divided .scale is engraved upon 

 the draw-tube, so that the position may be recorded. It is made 

 in the following magnifying powers : — 



For the six -inch tube length. 5, 7, 10, and 14 diameters^ 

 For the ten-inch tube length, 7, 10. 14, and 20 ,, 

 The cost is very little greater than that of the Huyghenian 

 eye-pieces. 



THE FACE OF 

 By A. 



THE SKY FOR OCTOBER. 



Fowler, f.r.a.s. 



THE SUN.— On the 1st the Sun rises at 6.2, and 

 sets at 5.38 ; on the 31st he rises at 6.54, and 

 sets at 4.84. Simspots are not likely to be either 

 numerous or conspicuous. 



The Moon. — The Moon will be new on the 4th, 

 at 7.14 P.M.; enter first quarter on the 12th, at 6.10 .\.m. ; 

 will be fuD on the 18th, at 10..) p.m. ; and enter last quarter 

 on the 26th, at 9.40 a.m. The following occultations are 

 the most interesting during the month : — 



The Planets. — Mercury is in superior conjunction with 

 the Sun at 4 a.m. on the Ist, and will, therefore, be an 

 evening star throughout the month. He is, however, un- 

 favourably placed for observation on account of nearness to 

 the Sun and southerly declination. 



Venus has now become an evening star, but is still too 

 near the Sun for observation. On the 26th, at 6 p.m., she 

 wUl be in conjunction with a Librte, the star being 0° 6' S., 

 but both star and planet will have set nearly an hour 

 before this event. 



Mars and Jupiter are both evening stars, but are too near 

 the Sun for useful observation. They will be in conjunction 

 with each other on the 11th at 5 p.m.. Mars being 1 11' S., 

 and both being very near to a Libra? : the planets, 

 however, will set about three-quarters of an hour after 

 the Sun, so the conjunction can hardly be considered 

 observable. 



Saturn remains in the southern part of Ophiuchus, and 

 may be observed in the early evening, low down in the 

 south-west, under favourable conditions. Near the middle 

 of the month he sets about 7.40 p.m. The rings are 

 widely open. 



Uranus is not observable. 



Neptune, in Taurus, may be observed by those prepared 

 to take the trouble to identify it. He rises about 8 p.m., 

 and is situated in the Milky Way, nearly midway between 

 (^ Tauri and vj Geminorum. 



The Stars. — About 9 p.m. at the middle of the month, 

 Auriga and Perseus will be in the north-east ; Taurus low 

 down in the east ; Aries, Pisces, and Cetus in the south- 

 east ; Andromeda and Cassiopeia high up and a little south 

 of east ; Pegasus and Aquarius in the south ; Cygnus high 

 up to the south-west ; AquUa, lower ; Lyra and Hercules 

 towards the west ; Corona towards the north-west ; and 

 Ursa Major in the north. 



Convenient minimum of Algol occur on the 7th at 10.18 

 P.M., on the 10th at 7.7 p.m., and on the 30th at 8.50 p.m. 

 It wiU be interesting, too, to watch Mira Ceti, which should 

 be at or near a maximum about this time. 



(JEJjcss (Column, 



By C. D. LococK, b.a. 



Communications for this column should be addressed to 

 C. D. LococK, Netherfield, Camberley, and be posted 

 by the 10th of each month. 



Solutioyis of September Problems. 



No. 1. 



(By H. Bristow.) 

 1. R to Q2, and mates next move. 



No. 2. 



(By P. G. L. F.) 



Key Move — 1. K to B5. 



Ifl. . . . Kt moves. 2. Kt to Kt6ch, etc. 



1. . . . P to Q6. 2. Q to R4ch, etc. 



1. . . . B moves. 2. Q to RGch, etc. 



Correct Solutions of both problems received from 

 A. H. Doubleday, Alpha, J. Baddeley, N. M. Muuro, G. C. 

 (Teddington), W. W. S., .J. E. Lelliott, W. de P. Crousaz, 

 G. D. Crowther, Capt. Forde, H. Le Jeune. 



Of No. 1 only, from A. J. Head. 



Mexfield. — The work referred to is not published. 



