Observatio Eclipsis Lunae Die 27 Martii, Ann. 1755. Habita Ulissipone in Domo Patrum Congregationis Oratorii à Joanne Chevalier Ejusdem Congregationis Presbytero, Regiae Londinensis Societatis Socio, Regiaeque Parisiensis Scientiarum Academiae Correspondente

of; whether air be mixed with, or necessary to, its formation; as also how far its power of resistance may reach; are probably not yet known, to a proper degree of exactness. Niewentit fixes the expansion of a cubical inch of water, converted into steam, at 13365, Dr. Desaguliers at 14000, and Mr. Payne at 4000 times. The great scope in this subject from a plenum to a vacuum, if I may be allowed the expression, as also the very useful purposes, to which it has already been, and possibly may be still further applied, will, I hope, be an inducement to those, who are much better qualified, to proceed in so useful an inquiry. XLVI. Observatio Eclipsei Lunae Die 27 Martii, Ann. 1755. habita Ulissipone in Domo Patrum Congregationis Oratorii à Joanne Chevalier ejusdem Congregationis Presbytero, Regiae Londinensis Societatis Socio, Regiaeque Parisiensis Scientiarum Academiae correspondente. Tubo optico 8 pedum peracta est observatio cælo sereno, claroque. IMMERSIONES. | Read Dec. 8, 1757. | Initium penumbrae dubium | Initium eclipsei dubium | Certe jam incæperat | Umbra ad mare humorum | |------------------|--------------------------|------------------------|---------------------|----------------------| | | Nitium penumbrae dubium | Initium eclipsei dubium | Certe jam incæperat | Umbra ad mare humorum | | | 10 29 50 | 10 33 35 | 10 34 05 | 10 44 00 | Hora postmeridiana temporis veri. | Umbra ad Grimaldum | 10 44 53 | |---------------------|---------| | Grimaldus totus in umbra | 10 47 58 | | Mare humorum totum in umbra | 10 51 14 | | Thico incipit mergi | 10 53 29 | | Thico totus mergitur | 10 55 14 | | Umbra ad Reinholdum | 11 08 04 | | Umbram ingreditur Copernicus | 11 19 22 | | Umbra ad mare nectaris | 11 24 52 | | Totum in umbra | 11 33 50 | | Umbra ad mare tranquillitatis | 11 35 24 | | Promontorium acutum in umbra | 11 45 46 | **Emersiones** | Incipit emergere ab umbra Copernicus | 12 04 38 | |------------------------------------|-----------| | Totus Copernicus extra umbram | 12 07 40 | | Incipit egredi Grimaldus | 12 09 38 | | Totus Grimaldus extra umbram | 12 12 38 | | Incipit emergere mare fœcunditatis | 12 31 37 | | Emergit mare humorum | 12 36 11 | | Incipit emergere Capuanus | 12 39 40 | | Egreditur Schicardus | 12 48 30 | | Emergit Thico | 12 51 40 | | Totum mare nectaris egreditur | 12 58 09 | | Finis eclipsis | 13 13 02 | | Finis penumbrae dubius | 13 16 50 | XLVII.