SCIENCE. 



i 



5i8 



edge cf the candle, just under the wick, in order to con- 

 duct away and diffuse through itself the vibrations of 

 heat. At first I had a series of these metallic collars, 

 and proposed to remove them as the candle burned 

 down ; but I afterwards found that one or two good 

 thick zinc collars would be sufficient. 



Here is a candle from my cigar blow-pipe case which I 

 am at present using, and another unused one, as made for 

 me by Price & Co. of Battersea. 



(4) CANDLE SCISSORS. 



In Plattner's apparatus scissors are supplied for cut- 

 ting the lamp-wick, which of course can also be used for 

 other purposes, and also a pair of pliers for squeezing 

 the wick together, and pressing it in any direction ; these 

 latter cannot be used, from the dirty state into which 

 they get, for anything else. I use these two articles com- 

 bined into one — i. e., a pair of ordinary scissors with 

 knobs at the end. This also goes into my cigar blow- 

 pipe-case. 



(5) ORDINARY WATCHMAKER'S PLIERS, 



with a piece of wire-strapping round them, to enable 

 them to act as holders of platinum wire supports, and 

 they also act as the best cleaners of the wire by drawing 

 the latter from between the pressed flat sides. 



(6) TWO AGATE SLABS FOR GRINDING POWDERS. 



I have here got instead, a small Freiberg agate mortar, 

 with a pestle made from an agate pen, as I had no slabs 

 small enough to pack away in this cigar-case. 



('/) REAGENTS. BORIC ACID. 



It has always seemed to me as though blow-pipe work- 

 ers, or, as I call them, "Pyrologists," could no more pro- 

 fess to begin analytical operations by using a salt as re-, 

 agent, than the analytical chemist could say he intended 

 to begin his solution-work by using sodium nil rate in- 

 stead of nitric acid. By employing boric acid instead of 

 borax, therefore, in 1869, I at once obtained a series of 

 new, very pretty, and important reactions, especially in 

 the case of the alkaline earths, which formerly used to 

 be the weakest part of blowpipe analysis ; now, they are 

 one of the easiest. Space and time do not allow me to 

 describe these reactions here ; and, unfortunately, I have 

 brought no boric acid with me here in order to illustrate 

 them ; but here is a little German-silver cigar-light box 

 in which the acid is kept, as it does not thus deteriorate. 

 This also goes into the cigar-case. 



Phosphoric acid is another of my new reagents (when I 

 say " new," I mean that they are now 12 years old, but 

 new in the sense that they have not been as vet generally 

 adopted.) I use it instead of the old reagent " microcos- 

 mic salt." It affords, with several oxides before the 

 blowpipe, new and interesting colors, as in the case of 

 cobalt oxide, which imparts to it a very fine and pure 

 violet instead of the ordinary blue. Of course, wlv n a 

 sufficient quantity of soda to form metaphosphate of 

 sodium, or microcosmic salt after the ammonia has been 

 driven off, has been added, the bead becomes blue, and 

 this fact enables it to be used as an alkalimeter. Itisthe 

 only reagent which requires to be kept in a stoppered 

 bottle ; and is such a powerful acid before the blowpipe 

 that gold leaf is rapidly dissolved in it, yielding a brilliant 

 purple bead. It affords, with iron oxide, a bead the color 

 of watery blood. This ends the list of things packed in 

 the cigar-case. 



(8) A COMPASS IN WHICH THE NEEDLE POINTS E. 

 AND W. 



This is made by bending an ordinary magnetized needle 

 in the centre until the points are opposite, like a lady's 

 hairpin. It is, in fact, an ordinary horseshoe-magnet 

 suspended, and such a magnet suspended swings E. and 



W. for a very obvious reason. It might prove useful in 

 Arctic voyages, as such a needle would probably possess 

 little or no "dip." If you bend an ordinarily magnetized 

 needle at a right or any other angle, and suspend it from 

 or on its centre of gravity, a line bisecting the angle will 

 point E. and W., and it was such a needle I first made 

 in order to find a very delicate test for traces of iron in 

 ores. The more open or obtuse the angle, the more deli- 

 cate this test is. I call it the "Equatorial Needle.' 

 With a right-angled equatorial needle you can detect the 

 mere trace of iron in the ore Molybdenite. 



(9) AN ALLOY-BUTTON OF GOLD AND SILVER IN WHICH 

 THESE METALS HAVE BEEN PARTLY SEPARATED 

 BY THE BLOWPIPE ALONE. 



Many years ago I found that, if you heat an alloy of 

 two or more metals very gently with the blowpipe, so as 

 not to promote fusion, in which case the ball spins round, 

 and all the component metals are mixed again — that one 

 nearly pure metal invariably leaves the others, and ap- 

 proaches the source of heat. This is a case of gold and 

 silver alloy, in which the silver has approached the source 

 of heat, but the process can be admirably illustrated in 

 the case of a common bronze pin, in which the tin ap- 

 proaches the source of heat, while the copper remains in 

 the background. Such a process might obviously be 

 found useful in metallurgy on the large scale. 



ASTRONOMY. 



To the Editor of " Science." 



On the early morning of June 30, 1 881 , the definition 

 was very good. On no other occasion was Comet B, 

 1 88 1 , seen so clearly. As it appeared in our 8X-inch 

 refractor, it presented some peculiarities which I have not 

 noticed in any published drawings, and therefore mail 

 you the enclosed. 



The prominent features were an unsymmetrical pear 

 shaped coma surrounding the nucleus, two streams on 

 either side, and one directly opposite the tail, which 

 blended with the envelope. Around the whole was a 

 very faint secondary envelope. 



Very respectfully, 



Isaac Sharpless. 

 Havekfokd College Observatory, September 1, 1881. 



