HARDWICKE'S SCJENCE-GOSSIP. 



and a shilling per volume more for binding decently 

 in cloth. Such being the case, the anti-climax to 

 which I have alluded is simply inconceivable. On 

 application being made for copies to be sent to our 

 public libraries, the Government has declared that it 

 cannot afford these few ninepences per pound and 

 shillings per copy. 



Compare this with the proceedings of the Go- 

 vernment Printing, Office at Washington, whence 

 are issued the noble records of " The United States 

 Naval Observatory," &c. These are not only dis- 

 tributed freely to the American public libraries, but 

 are sent across to the scientific libraries of Great 

 Britain, and not only to them but to individual 

 members of the scientific societies. I have a very 

 valuable series of these reports, and of the Reports of 

 the "Department of the Interior," and other works 

 issued by the United States Government from their 

 Printing Office at Washington. These are sent over 

 to me through their agent, and carriage-paid to 

 London, upon no other asking than that of replying 

 to an official letter enclosing a list of works from 

 which I am asked to select those I desire to have. 

 Generally speaking they are invaluable as original 

 records of most important and laborious scientific 

 investigation. All Englishmen desiring to be patriotic 

 must be bitterly ashamed of this melancholy contrast. 



The present favourable position of the most won- 

 derful and beautiful of all the heavenly bodies, the 

 planet Saturn, with its mysterious ringed appendages, 

 reawakens an old project that I have often longed to 

 carry out, viz., the establishment in a suitable part of 

 London of a popular observatory. I don't mean an 

 establishment with amateur observers pretending to 

 do original astronomical work, and thereby supple- 

 menting or superseding the Greenwich business ; but 

 simply a good astronomical peep-show, where millions 

 of people who have never looked through a powerful 

 telescope, and otherwise never would do so, might 

 have an opportunity of seeing for themselves some of 

 the magnified glories of the heavens. I believe that 

 it might be made commercially self-supporting if 

 well done, and all pedantry severely excluded. No 

 mathematical work could be done nor need be at- 

 tempted. Both reflecting and refracting telescopes 

 equatorially mounted with the simplest of efficient 

 clockwork would be required ; and one telescope 

 should be provided with spectroscopic appliances. 

 The physical phenomena are all that the popular 

 visitor would desire to see, and the fact of having 

 once seen the most striking of these would leave a 

 life-long impression on all intelligent men, women, 

 and children. A small charge, with proper regula- 

 tions as to time allowed at each instrument, would 

 cover all expenses, including a modest salary to the 

 showman — I beg his pardon — the director. The sun 

 and moon should be shown first with a low power to 

 display all the disc, then with a high power for 

 particular details. 



Apropos to telescopes, Mr. Cowper Ranyard lately 

 read to the Astronomical Soeiety a note on the 

 blurred patches that appear in the splendid photo- 

 graphs of the sun taken by M. Janssen at Meudon. 

 Janssen is himself inclined to attribute them to solar 

 clouds or gaseous matter above the photosphere, but 

 Mr. Ranyard has made some experiments indicating 

 that they have their origin within the telescope itself, 

 and are due to heated currents of air in the tube. He 

 produced exaggerated representations of these in the 

 form of ripples by placing a heated body inside his 

 telescope. The difficulty of maintaining a perfect 

 calm wdthin the tube of a large telescope must be 

 great, and the sensitive film used for these instan- 

 taneous photographs cannot fail to display any dis- 

 turbance affecting either the transparency or re- 

 fractive power of the air in the telescope. I think 

 the question as between these two explanations might 

 easily be settled by taking several pictures of the sun 

 at short intervals apart. If the light patches or blurs 

 are due to cloud-matter in the sun they should 

 appear at the same place in all the pictures, seeing 

 that the space represented by every square milli- 

 metre of such pictures is so enormous that no cloud 

 could travel to a sensible distance on the picture in any 

 short period of time ; while, on the other hand, the 

 atmospheric irregularities within the telescope must 

 be visibly shifted during small fractions of a second. 



DESCRIPTION OF A CONVENIENT FORM 

 OF LIVE-CELL FOR OBSERVATION 

 WITH THE MICROSCOPE, AND OF AN 

 INEXPENSIVE MICROTOME. 



THE main drawbacks of most cells for the obser- 

 vation of living objects are that they either 

 leak, or are very difficult to clean. The under- 

 described t form, which I have lately contrived and 

 used, obviates these defects, and may therefore be of 

 interest to the readers of Science-Gossip. It is of 

 very simple construction, and can be made up at a 

 trifling cost by the help of any ordinary metal worker. 



Take a stout ground-edged glass slip, and have 

 fitted to it two sheaths of thin brass, about i|-irich 

 wide. These should be made to fit closely, but not 

 so tightly as to prevent the glass slip from sliding 

 easily through them. To the middle of one end of 

 each sheath is soldered a small brass arm (shaped as 

 in Fig. 2), carrying a fine screw on one arm, which, 

 when secured in position, projects about 5-inch 

 beyond the end of the sheath. 



A piece about ij inch long, cut off a thin glass 

 slide, and a thick india-rubber ring (those used for 

 Cod's patent soda-water bottles serve excellently) 

 completes our requirements. 



To put the parts together, slip the sheaths, one on 

 to each end of the glass slide, with their two little 

 screw arms projecting towards each other. Now cut 



