ftl5 A new Cement. — GrerCs Eudmneter. 



and dried in wooden boxes, or upon an extended cloth. Th^ 

 liquid which remains, as v.eli as the water of the firft wafli- 

 ing, may be employed feveral tunes in fuccjfTion tor new 

 operations, by ditioiving in it frefli portions offal ammoniac 

 tp tlie point of firmation. Tiuee parts of the muriat of 

 ammonia are fafficient for two parts of copper, and the re-, 

 fj-ilt is lix parts of colour. This beautiful green is in Hol- 

 land called Friefland green. It is; almofl alvvays adulterated 

 v/ith cerufe. 



CEMENT FOR FILLING UP CRACKS AND FISSURES IN 

 IRON VESSELS. 



The fame author has alfo made known this cement. It 

 ponfilts of fix parts of yellow potter's clay, one part of the 

 filings of iron, and a quantity of llnfeed oil fufficient to form 

 the whole into a pafte of the couiiticnce of putty. 



(JREn's EUDIOMETER. 



Profeflbr Gren, m a work of his lately publifhed *, pro- 

 pof;::s the following mclliod of condructing an eudiometer 

 by means of phofphorus; which, though flow in its opera- 

 tion, will H,i\'e a very accurate refult. Take a fmall cyl'n- 

 dr"c n;lafs tube, fcaled at the one end, and divided from that 

 end by means of a fcale into fufficicntly fmall equal parts ; 

 fill it with diftilled water, plunge it into a bafon of the fame 

 liquid, make to afcend a quantity of the air to be examined, 

 and note the flate of the atmofphere at the time, as indi- 

 tiated by the barometer and thermometer. Through a cork, 

 fmaller in diamcLer than the tube, flick a few needles, a,nd 

 place on the upper end of them abit of pure clear phofphorus: 

 faften a thread to the bottom of the cork. Introduce this 

 cork into the lower end of the tube, with the phofphoru^ 

 uppermoft, in which it will rife to the furface of the water ; fo 

 that the phofphorus on the needles will come in contaft withi 



f Grundrifs der Natuvlehre. Halle, 1797. 



th,e 



